From right to left...end cap assembly (with brushes)...frame...front end cap. Second row...armature...drive pinion...shield retainer...spring...pinion stop...hex nut. On the bottom are the through bolts.

I should have read this sticker before I lightly tapped the starter with a hammer. Note to self...only tap on the end of the starter.

Three pictures of what the inside magnet should look like and what some of it looks like now. I am going to clean it and put it back together. It may not work because of the broken magnet or it may have a dead spot.

Better shots of the end cap with brushes...there is a spring under the brushes, which keep the brushes up against the bottom of the armature.

The hard part in putting this back together, is to hold the brushes in place while trying to place the armature. I fabed up four clips out of sheet metal for this purpose.

Place the frame over the armature...line up the bolt holes and put on the front end cap...bolt together.

Only things left are the pinion, washers and spring, and hex nut.

Now it should look like when I started, with no parts left over. Need to put it back on the tractor and hope. I do intend to switch out this starter, because of the broken magnet, but I may have bought a little time.

Most of the starter problems on the Kohler engines can be fixed by taking off the starter and cleaning the shaft the pinion slides on with WD-40. When the pinion starts sticking, that's when you start wearing things out . You can usually see if the pinion is operating correctly just by looking down at the starter end. Hope you enjoyed and hope this will help some of you.

The 300 and 400 series Wheel Horses can be broken down to three groups when it comes to basic wiring. 1985 and 1986 all had K series Kohler engines with battery powered ignition systems with the exception of the 1986 308-8 which was a Magnum M-8 and the 1986 420LSE which was Kohler powered with a M-20. After all, this is Wheel Horse so there had to be exceptions. 1987 to 1997 were M series Kohlers and 1998 and later were Kohler Command powered.

All 300 and 400 models that were equipped with Kohler Magnum engines from 1987 to 1991 used the 103991-ignition switch and from 1992 to 1997 they all used the 116338-ignition switch. These two switches are not interchangeable and the method of transitioning from magneto ignition to battery ignition was a bit different depending on the ignition switch. (see switches below)

The goal was to avoid having to rewire the tractor while retaining the safety switches. The seat and PTO switches on a magneto ignition system are wired in series while the seat and PTO switches are wired in parallel in a battery ignition system. With the use of inexpensive automotive 5 pin relays, I was able to come up with a satisfactory solution that isn’t too involved.

Utilizing this method the engine will shut off whenever the operator leaves the seat regardless of the PTO switch position. This is a bit inconvenient but it is the only way I could find without rewiring the safety switches. The wire gauge used on the safety switches of a magneto ignition tractor are too small to be used for a battery powered safety switch system.

First, we will cover the modifications needed for the 1987 to 1991 300 and 400 series that have a 103991 ignition switch.

Since the Ignition switch does not have power to the "A" (accessory) terminal in the Start position we will use one relay to provide 12 volts to the ignition coil during Start. This will be done by running a wire from the small purple wire on the solenoid to the relay terminals 30 and 85 to finish 12 volts coming from terminal 87 of the start relay to the ignition coil + when the relay closes. Placing the ignition switch will provide power to the small purple wire actuating the relay and passing power to the ignition coil if the operator is in the seat.

The Dark Blue wire from the PTO switch that presently goes to the magneto coil will be disconnected from the PTO switch and eliminated. A wire from the seat switch light green side will be connected to relay terminal 86 to allow the relay to close if the operator is in seat during Start. (see start diagram)

Once the engine starts and the key is released the white (sometimes pink) wire from the voltage regulator to the ignition switch “I” terminal will have voltage to it.

When the key is released to the Run position the second relay will provide 12 volts to the ignition coil. The white wire from the voltage regulator to the ignition switch will be spliced into and connected to relay terminals 30 and 85. The ignition coil and light green seat switch wires will be the same as the other relay.   (see run diagram and combined diagrams)

On the later 1992 to 1997 models with the 116338-ignition switch a single relay can be used because the “L” (light/accessory) terminal has power in the Start and run positions. This wiring would be the same as the run diagram.

Right now I'm thinking of following Kevin's advice but let's hear it from the peanut gallery, er, I mean experts. :thumbs:

thanks

   I'm writing this post to help clear up that question, first this only applies to 10, 12, 14 and 16 HP Kohlers, they used two style blocks commonly referred to as large or small base blocks.

  We will start with the large base or eared block used on most WH tractors from 1967 to the last Magnum about 1987, these blocks use the bigger oil pan, and the pan bolts on from the top side through ears on the block, this style oil pan is the one that bolts directly to the frame, the two bolts on the right side that hold it to the frame go from under the frame into blind bolt holes in the bottom of the pan, the pan will hang over the frame some on that side, with the mounting ears on the pan NOT being used.

This is a large base block and pan, note how long the pan is and where it bolts to the block

Here you can see where the pan hangs over the frame, at this point under the frame is where the bolts go from the bottom in to the blind holes in the pan.

The holes outlined in red are the blind holes used to bolt the pan to the frame from the bottom, the holes in green are the ones that hang over the frame.

Here you can see the bolts that hold the pan on, going through the ears in the block.

That pretty much covers the large base blocks.

Next is the small base block used on the shaker plate engines, and some of the mid 60's 10hp engines in WH tractors,  this style block is also common in Cub tractors, and others but we are talking WH here.

  The small base block the oil pan bolts on from the bottom of the engine, it does not have ears on the block, the pan is closer to a square in shape than the large base block, here is a pic of a small base block and oil pan.

There are many many styles of oil pans to fit the small base block, other brands of tractors use pans in all shapes, and depths so when swapping this style pan you have to watch how long the oil dipper is on the bottom of the connecting rod, it can be cut to fit a shallower pan, WH used two basic pans on this engine a very shallow pan on the early 10 hp and a mid depth on the shaker plate engines.

This pan is a shaker style pan used in the late 70's early 80's on the shaker engines

This pan is the flat bottom style used on the 1045, 1055, 1075 and 1046 also used on many Cub engines and other brands, the dipper on the connecting rod is very short on the engines that use this pan.

This is a deep pan on a Cub engine, I do beleive it uses the same dipper as the large base blocks with the big oil pan.

  Here is a shot of both styles together, to give you a idea of how the blocks look side by side, note on the large base block the cut outs at each end, I will be talking about them and the 4 holes you see where a small base oil pan could fit with a few mods. 

Here are the pan gaskets side by side and over top of each other.

Ok now we will talk about how a small base oil pan can be used on a large base block, note the red circles they point out the cut outs in the block where the small oil pan will not seal, this area can be filled up with JB weld or other compound that will stick to metal and take the heat, then note the green circles they show the holes that will need to be tapped to bolt the pan to, so far all blocks I have seen have the holes but are not tapped, with these mods a small pan can be used on this block, also if needed you could cut most of the ears off the block.

Now some blocks (very few) are set up from the factory to except both style oil pans, most common found on JD tractors as they use a shaker mount set up that uses the ears on the block to mount it but still uses a small oil pan, here is a duel pan style block note is does not have the cut outs in the block like a normal large base block does.

Just remember to check the dipper on the rod, to long and it will hit the pan, to short and it may not splash lube properly.

  I hope this helps clear up a few questions about block styles and how they differ 

i initially thought I had a fuel issue or dead fuel pump or something. I rolled it to the side to troubleshoot later. Well last weekend I did some investigating and I had no spark. I swapped trigger with one I had scavenged off my GT14 parts tractor. I had cleaned it up but never tested it or proved it good. Same resulted.

Tractor still had original regulator and readings were marginal as my findings were pointing to the trigger. As such I went ahead and ordered a new regulator. Today I installed and same results. But at least I will have greater confidence in regulator once I get this resolved.

What is everyone's experience with these trigger modules? Are they fragile or robust? 

I would prefer coil, condenser and points but the block is not set up for points.

The only triggers available are very pricey. May be better to find a replacement K321/341 with set up I prefer.

On a side note, would the internals of the Current K321 interchange with another set up with points? I believe they would but assumptions are worse than worthless. 

Pic ice of one that came off and the freshened up one I installed with same results.

Here is the carburetor:

Carburetor number: 104 5B18

So I remembered that @buckrancher told me years ago that there is a metering rod that sits in a shaft along side the main jet.

In order for the engine to run properly, that rod needs to be free inside the shaft. If you can't here it rattle when you shake the carb, it has to be removed and cleaned. 

This is where the rod is located, under a small plug.

After carefully drilling out the plug, here is the rod sitting in the shaft.

It definitely was stuck and would not come out, So after spraying brake cleaner in the hole and letting it sit over night, the rod came loose and came out with a little prodding.

As my research has found, there are many tiny little holes or ports inside the carburetor that need to be cleaned, especially if ethanol laced gasoline has been left sitting in it.

One of those little holes goes through the side of the shaft that the rod is in, and into the main jet area. That hole is accessed by another plug on the side which I had to drill out.

Here is a .5mm wire that I inserted to clean the hole. 

Next step is to find more tiny holes to clean, then continue.

I removed the 9/16" Welch plug.

The vent hole on the outside goes directly to the bottom (or top as it were) of this cavity.

This hole is now cleaned and the new Welsh plug is installed.

Next step is to remove the 7/16" Welch plug on the outside, above and to the left of the idle adjustment screw.

The hole indicated by the red arrow goes to the idle screw area, and the two holes with green arrows go to the the idle and progression holes located near the throttle shutter shown in the next picture.

Holes are all cleaned and a new Welch plug will be installed later.

Next step is to remove the float valve seat. This is a little rubber donut.

This is removed and the new one inserted with a Tecumseh float valve tool (available from Amazon)

One end is a hook, the other an insertion tool. The hook is pushed through the hole in the seat and pulled out

Next step is to insert the new seat.

This carburetor, being as old as it is, does not have a replaceable emulsion tube (main jet). So the brass tube can only be cleaned.

This is the bottom of the emulsion tube.

This is the top. Notice the build-up of crusty deposits on the top.

This, and the inside of the tube will need to be cleaned.

Using a brush and rod, the emulsion tube is now clean.

The new float valve seat is prepared for installation, then inserted.

Both of the Welch plugs are tapped into place

Final assembly is begun.

Install the float with new needle, and adjust the float height to 11/64". I used a drill bit for measurement.

Install bowl with new gaskets.

Set the rough adjustments of the needle valves according to the Tecumseh book.

And now we are ready to install on engine and test.

MORE TO FOLLOW

Duke

    The only "special" tools I use for teardown and measurement are a set of telescoping gages, a dial or digital caliper that reads to .001"  (I prefer digital it takes out some guess work), a valve spring compressor and a harmonic balancer puller (for the flywheel) all four of these items I use can be bought online or from HF and are relatively cheap and can be used for other projects. 

Tools needed for assembly are a ring compressor, shim gages, a valve lapping tool with compound, and a torque wrench (none of these tools have to be top of the line, I use a $30 in/lb torque wrench for the connecting rod and a $50 ft/lb  torque wrench for the head gasket bolts. ( the last two can usually be borrowed from a friend  if you don't have them.

two notes:

The short bar ,right side of tool picture, is made from a piece of 3/8 flat stock. It is 1.772 long and the ends are rounded to fit in the outer bearing bore of the bell.

The ring is 5/16 thick to be used when installing the inner bearing. It sets the bearing to allow installation of the seal.

Hope this will be helpful to someone.

Marv

For those of you that do not know, I race Lawn Mowers with the United States Lawn Mower Racing Association. I compete at the top level of Lawn Mower racing, the Sta-Bil Lawn And Garden Mower racing Series. I race the #M37 Cool Rides Online mower in the C/P Class.

After Several inquiries as to speeding up tractors I decided to do a write up on just this subject. So let’s speed up that Horse!

Put a 6†pulley on your engine, and a 4†pulley on your tranny and you will boost the speed of your tractor to approx 10MPH...

But that isn’t enough...LETS GO FAST!

WHOOAAAAA BIG RED!

You did not think it was going to be that easy did you!

First thing, before we talk about gears and pulleys and revs and all that jazz….lets look at a few things! LIKE SAFETY!

Your tractor is a tractor, not a go-cart! Tractors are made for working, not flying around the neighborhood. There for, many of the components on your tractor were neither designed for , nor are they correct for High speed applications!

First of these being the brakes! Higher speeds are much harder on brakes. That little band brake that will flip you out of the seat at 7mph…won’t do much more than make some smoke at 30 MPH! On USLMRA Racing mowers we upgrade to some pretty serious Disc Brakes, some of us running front & Rear brakes so that we can safely Whoa up our trick Pony’s!

Next is Wheels; Now compared to most, WH’s have some strong feet, but speed is hard on wheels! On our sanctioned class racers we upgrade to some pretty stout stuff!

Along with wheels comes steering; That wobbly gobbly thing we call a “Good Strong Front end†is not near stable enough for high speed application.

One of the biggest things is Stability; A USLMRA Prepared Class racer sits as low as 4†Off of the ground, has a 38†tracking width, and weighs in the neighborhood of 300-350 pounds, give or take. With our tractors sitting 3 times or more than that up, several inches narrower, and two or three times the weight…..things get interesting REAL quick! Having a 600 or more pound tractor land on you can get way past dangerous in less than a heartbeat.

Now that we have considered how unsafe this venture can be…why else DON’T we want to make changes to the gearing of our tractor?

How about your engine? More than likely, without some major modifications, that K91 is NOT going to pull a doubled up gear ratio!

How about your tranny? WH trannies are NOT models of efficiency. They may be great for the job they were intended, but when it comes to high speed application they would not be your first choice, or second….or 23rd? Over speeding them can have catastrophic effects on them, to the point of actually blowing them apart. Do you really want to do that to your 50 Y/O treasure?

Finally there is the subject of the purpose of your tractor. If you ever connect any type of attachment or implement to your tractor you DO NOT want to speed it up! Plain and simple here gents, without re-engineering and re-gearing your transaxle, you cannot speed up one gear without speeding up all of them.

Tractors are made for working, and Wheel Horses are capable of some simply amazing feats when you consider the amount of work they get done for the size of engines they have. The minute you start increasing speed you decrease the amount of work your tractor can do. And as far as mowers or snow blowers go go, excessive speeds on rotating attachments can be fatal, for the attachment and the operator! You start speeding it up, forget about dirt work, snow pushing or all that other “Tractor†stuff with your now very poorly designed Go Cart!

SO just so we are clear, if you decide to proceed beyond this point…

I AM ABOUT TO SHOW YOU THE EASIEST AND QUICKEST WAY TO MAKE YOUR TRACTOR USELESS AND WORSE YET....SPILL YOUR BEER!!

Now that you have decided to ignore my very intelligent and worthy cautions.....lets get to the fun! You can slightly “boost†the speed of most tractors without any major ramifications...so for youthat want to make your 7MPH Horses go a whopping 9MPH...or get really out there and hit the double digits at say 12MPH!! here is the goods!

Making your tractor faster is relatively simple, it takes a little bit of math, some minor mechanical ability and fabrication skill.

The speed of a tractor has 3 basic elements; The speed of the engine, the overall gear ratio and the size of the tires. Now immediately someone is going to tell me I forgot the SIZE of the engine. In theory the engines size or power does not determine how fast the tractor will go but rather how long it will take it to get to that speed! In actuality, if you do not have enough engine to get the thing rolling in the first place...the amount of time it takes to reach top speed is exactly never!

We are going to focus on the second element only. The engine build is an entirely different subject, and I am going to assume most of us already have our tires. So what you guys really want to know is, how to manipulate your gear ratio.

Simply put, the overall gear ratio of a tractor is a comparison between how fast the engine turns and how fast the axle turns. The fewer revolutions your engine makes for every revolution of the axle, the faster your tractor goes.

The overall ratio on a WH is broken into 2 sections. The primary, or belt drive, consists of the engine pulley, the belt and the transmission pulley. The final drive, or trans-axle, consist of.....you guessed it...the trans-axle!

To find your overall Drive Ratio you Multiply your primary ratio by your final ratio.

To speed up your tractor, you must change one of these ratios. As I said earlier, there is nothing you can do about the trans-axle ratio without re-engineering the whole thing. The primary drive however, we can whoop the hell out of that!

How much speed you gain will be determined by how much you change that ratio..most of us would prefer to know how much speed we are going to get before we buy the pulleys. So NOW we are getting to what you really wanted to know.

I know....Rooster just shut up and tell me what size to get!

OK..A 6 on the engine and a 4 on the tranny...happy now?

If you want to know how I got those numbers...read on.

To determine your pulley sizes you need a formula...and here it is...

SO lets break that down a little....

Engine RPM: I usually govern “working†engines around 3500...so we will just use that #.

Tire Dia: This is the actual measured Height of your rear tires...not what is printed on the sidewall. For argument, we ar going to use 23â€Â

336: This is a constant derived from the circumf...ohhh you don’t care...just use the number!

Gear ratio: This is the thing we are working with...remember... To find your overall gear ratio takes another formula....

SOOOOOO

I believe most WH’s have a 4†engine pulley and a 6†tranny Pulley

We now have the complete formula for figuring speed.

So lets plug our numbers in here...

I believe most WH’s have a 4†engine pulley and a 6†tranny Pulley, and the final gear drives best my research shows on manual tranyy’s is 24.6/1.

Top Speed=(3500*23)/((( 6/4 )*24.6)*336)

80,500/(( 1.5 *24.6)*336)

80,500/((36.9)*336)

80,500/ 12,398.4=6.49 MPH

So, the speed of a Manual transmission Wheel Horse Tractor with 23†tall tires, at 3500 RPM is about 6 ½ MPH...more or less depending on how many beers you have had.

Now ….I still have not told you how to make it faster....

Simply change the pulleys...

Bigger on the engine or smaller on the tranny makes you faster.

Smaller on the engine or bigger on the tranny makes you slower...but you can pull more

How much faster is simply a matter of how drastic of a change you make.

To make this easier, I have made a calculator for you to use....Wheel Horse Speed Calculator

Insert your Pulley sizes, tire Diameter and engine speed and it will figure your Overall Gear ratio and top speed for you.

So now we are all done!

Oops....wait....your clutch doesn’t work anymore....dangit.

Here’s an Idea...since your clutch and belt are made to work with a 4†& 6†pulley....use those sizes, only put the 6†on the engine and the 4†on the tranny....where have I heard that before?

We still have a belt guard issue, which on many tractors is also a belt guide issue...which must be addressed. I am sorry to tell you, but I have not devised any other way than making a new belt guard?

As for the issue of attachments, all hope is not lost. You can buy “Stepped†sized pulleys. So your drive pulley would be the 6†and your attachment pulley what ever size the original was.

Here is some baseline detail of the throttle at idle and wide open, along with choke operation.  The exhaust has been modified and bugger welded quite heavily, that’ll change some day too.

John

http://gardentractorpullingtips.com/carbfuel.htm

The procedure below explains how to renew a flat(ter) surface on the cylinder head gasket sealing area to prevent defects in the gasket surface from destroying additional head gaskets or the cylinder head itself.

Float glass is certainly not the end all argument for a perfectly flat surface but can easily provide sufficient flatness for the purpose of improving the sealing capability of a LGT tractor cylinder head.

In preparation for renewing the cylinder head, a few common items will need to be obtained from local suppliers. The surface of an ordinary pane of glass makes a very suitable flat surface to perform this procedure. Several sheets of Wet/Dry 220 grit waterproof paper will be required. Water in a spray bottle will be needed to wet the abrasive paper to keep aluminum debris from collecting on the abrasive paper and clogging the grit prematurely. Wetting the glass pane slightly will allow the paper to "suction cup" itself to the glass pane when the cylinder head squeegees the water from underneath the paper.

The cylinder head pictured below will be used for this process. This is a high compression head from a Cub Cadet 10HP Kohler engine.

To observe the progression of material removed from the head, I apply a very light "guide coat" of black spray paint to the gasket sealing area of the cylinder head. Complete removal of the guide coat will signal the completion of the flattening process.

First, establish a stable and flat surface on which to lay the glass pane. The float glass I used was 1/4" thick - pretty stout stuff. Edges of the glass were beveled for safety.

Make certain the glass surface is clean. Any detectable residue such a grease, dirt or stickers on the glass will cause a dimple in the abrasive paper and prevent the cylinder head from renewing perfectly flat. I usually run a single edge razor blade across the surface of the glass pane to assure no residue is present.

and onto the back of the abrasive paper. Allow the paper to soften somewhat so when flipped over, it will lay flat on the glass pane and hold the paper in place with "stiction"

Flip over the abrasive sheet and wet the top side to allow aluminum particles removed from the cylinder head to float away from the abrasive and not clog the sheet prematurely

Place the cylinder head gasket surface side down on the abrasive paper. I leave the spark plug in the head to allow for a better grip on the head throughout the process.

Move the head in an even figure 8 motion across the abrasive paper. Apply a slight downward pressure on the head and inspect the progress every 20 or so figure 8 rotations. The downward pressure applied to the head is approximately what you would use if you were applying polishing compound to car paint. No need for excessive pressure here, let the tools do the work.

After the first 20 swipes, inspect the head to check your progress. Notice the black guide coat is being abraded away on the "high spots" on the cylinder head.

Another 10 to 20 swipes on the abrasive paper and inspect the progress. The blacked areas are the guide coat still present in low spots between the areas polished by the abrasive paper.

Another 20 or so swipes and note how the shiny portion of the gasket area is increasing in size.

Another 20 swipes

And the final 20 swipes produces a gasket seal area without any evidence of guide coat left

The head material removed during the process . The slurry produced from this process is also highly abrasive. You may want to keep the slurry away from any nearby hand tools or power tools.

The final step is to gently wash away any silicon carbide material from the glass pane. Rinse the pane prior to wiping it down so as not to rub any abrasive into the glass surface.

Duke

Building and Using a Leakdown Tester

by Mike Nixon

A Better Way

Everyone remembers how to do a compression test: screw in the tester, flip the kill switch to "off", hold the throttle wide open, and press the starter button. The cylinder takes in air and compresses it, and the tester traps it. The maximum is reached when the gauge holds more pressure than the engine can produce. The weakness of this test is that throttle position, engine temperature, ambient air temperature, and a host of other factors can make the results vary considerably. What's worse, a compression test checks too many engine components at the same time. A poor reading can indicate so many things, it's hard to tell which engine part is at fault without doing a lot of other tests. A leakdown tester avoids this difficulty. Air is pumped into the cylinder from an outside source, and the gauge reads the percentage that escapes, which not only eliminates all of the aforementioned variables, but as a bonus, makes it a simple matter to pinpoint the source of the leakage by wiggling and rotating engine parts while the test is underway.

"That'll be $1,500, and uhh, it still smokes."

But how does it work in action? Okay. Let's say your brother-in-law rebuilt your engine. You've suspected that the guy is mechanically challenged, and sure enough, the finished product smokes like a chimney. But he's your kin, so... Finally, you have a shop look at it. A good compression test combined with the smoking leads them to a diagnosis of trashed valve guides. Seems reasonable and you approve the work. And the engine still smokes. Now you really have a problem, not to mention the shop, and your brother-in-law. Enter Mr. Goodwrench, who produces a leakdown tester, and performs the following test. On each cylinder in turn, he sets up the tester and reads the percentage of leakage. They're all good and low. Hmm. Undaunted, our hero retests each cylinder, but this time he lowers the pressure setting on the instrument, and, rotating the crankshaft a smidge each time to slide the piston down the bore a little, picks up the problem, plain as day. On the #4 cylinder, the gauge now reads 60% leakdown when the piston is partway down the bore, indicating cylinder damage, which the teardown verifies. Seems your brother-in-law didn't get one of those pesky wristpin circlips all the way into its groove. It subsequently popped out, and the wristpin wore a handsome trench into the cylinder wall.

Why didn't the shop find it when the head was pulled for the valve job? Because two of the four pistons were at TDC. Why didn't the compression test pick it up? Because despite the trench, there is still plenty of cylinder area (the pin is more than an inch below the deck) in which to build adequate pressure for a compression test.

WHOOSH!

Leakdown testers are way cool. Not only does the amount of air escaping from the cylinder register on the gauge, it can also be heard, enabling the source of the leak to be pinpointed prior to the teardown. For example, high readings accompanied by hissing in the carburetor indicate burnt, tight, or carboned-up intake valves; the same thing in a muffler points toward--you guessed it--exhaust valves. A breeze coming out of the dipstick hole on the other hand indicates worn or heat-softened rings.

And air escaping from an adjacent spark plug hole pinpoints a blown head gasket.

Not For Everyone

There's a catch, of course. You need an air compressor to use a cylinder leakdown tester. And, you need to now how to find TDC (top dead center) on the compression stroke for each cylinder that is tested. Can you do it? Sure. If you can adjust your valves, you can use a leakdown tester.

Rolling Your Own

Ready-made leakdown testers are easy to find today. You don't have to mortgage your house to a Snap-On dealer. So, if you are concerned about the condition of your engine but aren't into making things, or don't have the time, you can buy a leakdown tester for about $75. If on the other hand you have an air compressor that sort of implies that you're a certified tinkerer. You're probably also into making things, and for you, throwing together a leakdown tester is no big deal.

Here's the rundown:

The pressure regulator

This is designed to be screwed onto an automotive paint spray gun. Grainger's is probably the cheapest, followed by Sears and Ace Hardware. The gauge that is often attached is, unfortunately, the wrong kind for our purposes.

The pressure gauge

Get a quality, back-mount, 0-100 psi gauge. As of this writing Grainger has the best deal. For the professional touch, carefully pry off the bezel and cover the faceplate with a copy of the label shown here.

The spark plug adapter

Make this by clamping an old 12mm plug in a vise (protected with wood or aluminum stock) on the hex--not the threads--and whacking off the porcelain with a well-aimed lateral hammer blow. Then grind off the rolled-over seal above the hex, grind off the ground electrode, put the plug back in the vise and drive out the remaining porcelain with a drift (if hard, the rolled seam hasn't been sufficiently removed--on some plugs you must grind partway into the hex to completely remove the seal). Tap the hex end with a 1/4" pipe tap (NGKs are hardest to tap but seal the best afterward). Screw the bugger onto a 1/4" to 1/2" pipe reducer, and that onto a 12" grease gun hose (about $5 at Wal Mart and just about anywhere).

The damper valve

This necessary part is merely a restriction between the regulator and the gauge. The easiest way is to plug the middle pipe with epoxy and afterward drill a 0.040" (#60 or 1mm drillbit) hole.

Using it

Adjust the cylinder to be tested to TDC compression (all modern inline fours firing orders are 1-2-4-3). Plug your tester into an air compressor line and adjust the regulator to get a "0" (or 100 psi, if you didn't remake the face) reading. Screw the hose into the spark plug hole. Connect the two. If the crankshaft turns or you hear all the compressor's air rushing out of an obviously open valve, the cylinder wasn't set exactly on TDC compression. Try again. When you get it right, the piston will stay put and the tool will indicate the amount of air that is escaping from around the rings, valves and head gasket of that cylinder. All cylinders leak a little. Large ones leak more, smaller ones less. Racing cylinders lose only 1 to 2%. Production multicylinder engines in top fiddle pass 5% and less, and no more than 10% regardless of the mileage. More than 10% leakdown means there's something wrong.

YOWIE!

In the event of a high reading, first take the time to double check that you are in fact at TDC on the compression stroke, not on the exhaust stroke (where both valves will be open). If that checks out, and the leak is (as it is usually) a valve, remove the valve cover and, with a hammer, carefully tap on one or both of the rockers for that cylinder, watching the gauge as you do so. This will often loosen carbon from around the valve and the reading will drop to a reasonable level.

Parts List

http://www.wheelhorseforum.com/index.php?...indpost&p=13481

I've been using it on bits and pieces for a few years now, and it does work well. A few weeks ago I threw in a hitch cable that was stiff, and the end result was so succesful I decided to try it on some completely frozen throttle and choke cables.

After a couple of hpurs in the bath, the cables began to move, but very stiffly. I worked them a bit and put them back in for another 2 hours. Pulled them out, blew throught with compressed air, blew through with WD-40, blew through with compressed air again and finished off with some 3in1 sewing machine oil. Both are completely useable now, free and smooth. I was amazed, and now will be able to use OEM origional parts on the old Lawn Ranger.

I'm stoked! :banana: :banana: :banana:

Looking to purchase a fram or other oil filter at a locate parts store like autozone etc rather than spend $20+ for oem. I have a 16 hp onan twin on my 91 416. Does anyone have the correct filter number and make? thanks-

I have 2 PTOs that I would like to rebuild. They both have bad bearings. I removed the needle bearing from one, but found that the outer case of the bearing is very soft material, and it gets damaged easily. I am afraid that I may damage the new ones putting them back in.

Any tips or pointers would be helpful. I do not have access to a press. Only standard mechanics tools.

Thanks

It won't start either. I pulled the oil bath and it fires up. Opinions??