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DarylJ

Kohler K181S seems starved for fuel....

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DarylJ

After doing a reconstruction from a total basket case, my old B-80 is finally back together.  There were some missing pieces, but with some scrounging, all the necessary bits are finally on the tractor.  As the carb was missing altogether, I decided to try one of the el-cheap units from the bay for $15.  The original fuel pump isn’t pumping, so in an effort to get it up and running, I bypassed the pump altogether and am relying on gravity feed for the purpose of seeing how it runs.  If all is okay, then will put on a new fuel pump.  But, today when attempting to fire it up for the first time in who knows how many years, it started on the second revolution.....and ran for a few seconds then died. Like fuel starvation, as it would not rev up to high idle.  Only slow idle.  Restarted it again with the same result.  Did this many times, while making adjustments to the carburetor to see if it could be coaxed to continue running more than those few seconds.  No luck.  Here’s the strange part....while the engine starts and runs those few seconds, at the same time there is excess fuel dripping out of the front air intake onto the floor.  I pulled the carb apart to see if the needle valve or float was sticking, but everything seems to be as it should, with float nice and level and operating without any hanging up.  There does not seem to be any obstruction of the fuel line, as a good flow of fuel makes it to the carb.  I’m about ready to proclaim the el-cheapo carb as the problem, but I want to be sure that I’m not overlooking something else that could be causing this.  Anyone here with some ideas or suggestions?

 

DarylJ

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wallfish

:WRS:

If excess fuel is flowing out the front, it's flooding, which means the float valve is allowing too much fuel and not completely sealing. Had the same problem with 2 cheapies.

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953 nut

:WRS:

I am inclined to agree with John, but it may have been something not lined up properly or a bit of trash in the seat and you could have resolved the problem while inspecting it. Can't hurt to give it a second try. Adjust the preliminary fuel setting to factory recommended, main jet (top) 2 turns and idle (right side) 1 1/4 turns out. Give it another try before tossing it out.

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pfrederi

Set the float at 11/64" above the housing several of the cheapies i bought were way off.

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DarylJ

Over the past two days, I have replaced the el-cheapo carburetor with another carb, this time an original Kohler I had on hand, then  replaced the ignition points and condenser.  Checked to make sure there was 12 volts from switch to coil as well.  Also removed the in-line fuel filter just to make sure it wasn’t impeding any fuel flow from tank to carburetor.  After doing these things, the effect on the problem was only a small, barely noticeable improvement.  

 

This morning found some more time to work on the K181.  Once again, I started It up and observed the following:  1. To keep the engine running, half choke was necessary.  While the engine kept running, a few drops of raw gasoline dripped from the front of the carb.  At the same time, a continuous puffing of fuel vapor came out the front as well.  Backing off the choke led to the engine stalling within a few seconds.  Also, manually advancing the throttle on the carb led to the same result, that of stalling the engine within seconds.  Whether or not the stalling was due to flooding, or fuel starvation....I am really not sure which it is. 

 

The engine will not start when the throttle is fully open.  Has to be half throttle to start up.  Also has to be full choke for a revolution, then off (no) choke to start.  Once started, as said above, has to be 1/2 choke to keep it going.  Once running, there is a quite noticeable click/hammer/clangy noise from somewhere internal. Pretty sure it is not a bearing, as it has a sharper sound to it.  Strange.

 

When installing new points, I rotated the flywheel to the imprinted  “S” mark coinciding with the indicator mark on the engine case.  At this point, the points began to open and were fully open to .020 once the flywheel rotated to the “T” mark for top dead center.  As timing is not something I know a great deal about, is it possible the timing, although the points seem to operate correctly, is substantially off?  Not sure the engine would start if the timing was off by 180 degrees, but someone here may know better.

 

I haven’t yet run a check on the coil, but plan to do so later today.  I have already switched out the coil with one from another tractor, and the result was no change.  The other tractor runs fine with the coil from this particular engine, so I presume the coil is fine.

 

Does anything I have described here sound familiar to you, and what did you find was causing this?  I have several other K181 powered WH tractors, and this is the first time I have been stumped on one.   Unless I am simply overlooking an obvious cause for why this engine won’t run as it should, my next move will be to park it until I can find some time to pull the engine out and open it up for exploratory surgery.  

 

Thanks for continuing to offer opinions and suggestions!

 

 

 

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DarylJ

Spent some time with the K181 again late this afternoon, putting a new fuel pump on it, as the old one wasn’t pumping at all.  I had bypassed it earlier, so it wasn’t part of the problem outlined initially.  Well.....after sitting by it to listen and adjust, listen and adjust, listen and adjust, I am now thinking that perhaps my problem is not with the fuel system or anything electrical at all.  That leaves the intake and exhaust valves as suspect.  The clattery noise....may well be valves.  As I haven’t had any valve issues with any of the other half dozen K181s I have around here, I don’t have any first hand experience with how they sound/act when there are valve problems.  Anyone here had any valve issues with a K181?  If so, did the symptoms resemble what I describe above?

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stevasaurus

Did you have to re-build this engine?  It seems that you have checked a bunch of stuff.  Pull up the manual for the Kohler engines...it is in the "Manual Engine Section on the main page and try adjusting the governor.  Put some pictures up here that show all of your linkage  Having to run with the choke out means you are sucking air somewhere.  Maybe that air filter thingy is not put together in the right order.  I'd do all this before I pulled the head and look at the valves...which is probably not your problem.

:think:

When it is running, you can spray some carb clean around the carb...where it mounts, etc.  if you get a rise in RPMs, you found your air leak.

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DarylJ

I have the manual and have adjusted the governor accordingly (loosen governor arm, rotate governor shaft counterclockwise, pull governor arm and linkage away from carb, tighten governor arm bolt).  Have done this on all of my other K181s as well, so am familiar with the procedure.  Linkages are correctly in place, same as on 6+ other K181s I have.  I have not rebuilt this engine.  It came without a carb, fuel pump, starter, or coil, so I put those on mostly with replacements I had on hand (except for new carb). BUT.....as mentioned above, I have now put two different carbs on this engine and it runs virtually the same with both carbs.  New gaskets, too.  Based on that, I’m now of the opinion that having both carbs dysfunctional in exactly the same fashion is probably not likely.   Your suggestions are well taken, though, so will go ahead and check for the leaks you suggest may exist.

 

 Earlier this evening, I did some more research into how incorrect valve clearances can and do cause some of the issues I am seeing here, including spitting fuel out the carb’s throat, lack of power, etc.  I don’t mind pulling the carb again (have done it at least a half dozen times in the past two days) to readily access the valves for the purpose of checking clearance.  If they are within specs and no broken parts (still want to figure out what the clangy noise is, too), then will go ahead and remove the head for further inspection.  Having a valve out of spec by a couple of thousandths I don’t worry about.  But, If one or both are out of spec considerably more, lets say ten thousandths, that will need to be fixed by taking the engine into the machine shop, as the K181 does not have adjusters on the valves.  They must be machined or ground to spec using equipment I do not have.  It’s the one feature of the K181 that Kohler skimped on, as the large block engines, beginning with K241 on up all had manually adjustable valves.  Regardless, the K181 is a great engine, light  and powerful, plus it sure makes for easier steering due to it’s relatively light weight.  The plusses far outweigh the minuses on this engine, IMO.

 

 

Edited by DarylJ
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Sarge

I'd have to say based on your descriptions it's either a valve or cam issue - or both. If it spits out the front of the carb, that intake valve is not seating correctly. Could just be some carbon buildup around the stem, that is common on neglected engines.

 

Sarge

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stevasaurus

Sorry @DarylJ...and Welcome to Red Square.  I did read that you had a few horses with K-181's, so I figured I was not just talking to someone that  was still wet behind the ears...and had things like linkages to look at.  If your fuel pump is throwing gas out like it should, then it is not toward the tank.  Checking that breather do-hicky will give you a look at your valve clearances...without pulling the head...and it is not a big deal to pull the head.  Have you taken a carb off of one of your other horses and tried that??  Following this to see what you find.  :handgestures-thumbupright:

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DarylJ

Late this afternoon, I pulled the carb off to access the removable cover/breather and check the valves for clearance and whatever else might be evident.  Exhaust valve was .008, intake was .000.  Strangely, the intake would SNAP shut with each revolution.  Wanting a better look at the camshaft, I next pulled the fuel pump to get a peek at what might be happening.  Rotated the flywheel to TDC, then inserted a small screwdriver through the fuel pump portal and nudged the intake lobe.  Loose and could be rotated about 1/2 a revolution.  Big problem!  Next move was to spend another half hour disassembling the engine to see what was going on with the camshaft.  Broken.  Fortunately no other damage to the internals.  Crank fine, cylinder unscathed, and shaft on which the cam rotates was unbent.  Sooooo, looks like it’ll be a few days to locate a replacement camshaft.  The cylinder has zero ridge, and piston is standard size, and the block is black.  This tells me someone put in a new short block at sometime and there are not many hours on it.  Why the camshaft broke isn’t evident, and no other debris was in the oil sump other than one small piece from the point of breakage.  

 

As I don’t have any way to grind the valve ends when setting clearances, much less any refacing or reseating equipment, this block goes to the machine shop immediately after finding and installing a replacement camshaft.  I’ll leave it up to them to make certain the valves are unbent, seat properly, and are not sticking, check the crank clearance, hone the cylinder just a bit, then take it back home for reassembly with new seals and gaskets.   Did a complete rebuild of another K181 (on C81 with exploded governor gear) less than a month ago, but fortunately it didn’t need a new camshaft.  So, teardown and reassembly are still pretty fresh in my mind. 

 

So, what I expected to be a fuel related matter only has become much more involved.  For me, that the engine could still run with a broken camshaft was totally unexpected.  With the camshaft broken and the valve train entirely out of sync, the fuel being spit and puffed out of the carb was due to the pressure of the piston compressing air and forcing it out through the carb at the same time the carb was sucking fuel and atomizing it for combustion.  But, there was enough getting into the cylinder to ignite, although only partially.  Although, most of the fuel/air mixture was being pushed back out through the carb and ended up dripping out the front of the carb barrel.  This explains why it was impossible to add throttle....not enough fuel mixture made it into the cylinder to increase revs.

 

Thanks to everyone for the warm welcome, too.  A bit of an introduction, here is a little about my history: I’ve been a low profile WH guy since the early 90s, having had a pretty good variety of models in that time, starting with a B-80, then caught round hood fever for several years, then some large block tractors, before finally settled down with my favorites, all 8 HP models (three B-80s , two C-81s, an 8 Four Speed, an 800 Special, and an 800 Automatic) except for one 520H, a 312-8, a B-100, a 953, and a 1054.  Every one get used regularly, mostly for pulling carts and trailers around the farm, but once in awhile are used with belly blade, push blade, tiller, and mower deck.  Have snowblowers should I ever need them, but that duty goes to a larger, utility diesel cab tractor (Deere 1050). No longer have any round hoods as I prefer platform type footrests instead of pegs.  But, sure do like the appearance of a nice, well kept round hood.

 

Once this B-80 is up and running, will post a follow up.  

Edited by DarylJ

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rjg854

Sorry to hear you must rebuild the engine,  but cool that it sounds like a simple more or less refresh. Even better yet, you'll have a good engine for many years to come. 

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953 nut
1 hour ago, DarylJ said:

 For me, that the engine could still run with a broken camshaft was totally unexpected.

Tells me that is a good Kohler and wants to run. Glad all the internals are fine.

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Sarge

Pretty lucky no debris got into the rings - crazy how they can break a camshaft and not grenade everything else. Spitting like that is always valve or timing related - glad it wasn't worse as most take out the other internal parts as a whole and destroy it. Hopefully, nothing got into the rod and tore up the crankshaft surface....

 

Sarge

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DarylJ

Definitely a silver lining to this story in that there was no further damage done.  The crank and rod surfaces are fine, too.  Will be removing the rings today to inspect the ring grooves and clean them of any carbon deposits that may be concealed.  Rotating rings presents no problems, they move smoothly.  Keeping fingers crossed that all is okay.

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DarylJ

The camshaft arrived and was installed into the K181 engine yesterday.  Finished puttting everthing back together this morning and started it up first revolution.  Everything now runs exactly as it should.  I am still amazed that this engine actually ran with a broken camshaft, but it did.  The clangy noise was caused by the cam lobe dropping the tappet with each revolution.  In case anyone has hesitated buying engine parts that were from a Kohler engine used on a competitor brand of tractor, it is what I chose to do with this used camshaft.  It came out of a K181 used on a small Deere and fit perfectly.   While this interchangeability of parts between brands worked with the camshaft, do NOT take it for granted that all engine parts, particularly externals, are identical across all tractor manufacturers that may use Kohler engines for power.  Specs will vary on an engine, depending on what the tractor manufacturer specifies for their applications.

 

Thanks once again to everyone who weighed in on this one by offering great suggestions and advice.

 

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