1968 Lawn Ranger won't start

[MSBiker 45]

Hi Folks,

Got an issue that is driving me nuts. I can't get this 6hp Tecumseh on this Lawn Ranger to start and run for longer than a few seconds. It takes starting fluid, or full choke, and a bunch of pulls (got the blisters to prove it) to get it started. Once started, it will only run for a few seconds, not long enough to get a screw driver on the idle adjust screw. I have put a new carb on it, same issue. Cleaned and installed old carb, same issue. No matter what, it starts hard and refuses to run longer than a few seconds. When running it seems to idle smooth, then staggers and stops.

* New carb set to 1 1/2 turns on idle and power. Old carb cleaned and set to the same 

* New plug gapped to .026 - 0.28

* Good spark when tested.

Just seems like it is running out of fuel, but like I said it is hard to diagnose when it starts so hard and does not run long enough to adjust. Any thoughts? 

[oliver2-44 8,862]

1st ditch the starting fluid. These engines were not designed for it and it could seriously damage it. 
 

Have you verified the fuel system is clean and fuel is easily flowing to carb. 
Also verify the small vent hole in the gas tank cap is open  

 

[MSBiker 45]

Drained fuel in tank and replaced with fresh fuel. Fuel seemed to flow freely. Fuel line looks original. I will change that even though there are no leaks.

[oliver2-44 8,862]

Just throwing out some long shots. Do you feel a good puff of exhaust air coming out of the muffler when you crank it. A restriction in the muffler such as carbon or collapsed internal can cause a back pressure. An engine has to “ breathe” out for it to have room to suck fresh gas carrying air in. 

Do you have an inline spark tester?  They help verify you don’t have an intermittent spark such as from a coil that grounds out internally from engine vibration. (If not, someone will be along with a recommendation for a good one as I have a cheap one I need to replace). 
To help narrow down if it is a fuel problem, have an assistant ready to give it small burst of sprayed fuel in the intake (air cleaner off) to see it that will keep it running. 
You can use spray can carb cleaner or gas in a squirt bottle in place of the starting fluid.  

 

[MSBiker 45]

Thanks, good ideas. I am unfortunately alone so I have to put that part off. I am going to research the fuel system not providing enough fuel. Besides, just got my JD hit miss engine from the machinist after a 4 month wait and need to work on it. Wheel Horse is next project on list. Thanks for the input. 

[oliver2-44 8,862]

1 hour ago, MSBiker said:

Besides, just got my JD hit miss engine from the machinist after a 4 month wait and need to work on it. 

We love pictures and write up about those kind of projects too. ( Even if it is Green)  You can post it in the other brands section. 

[MSBiker 45]

I will round up pictures as I go.

[RED-Z06 2,122]

Hows the compression feel?  Valves worn too tight can bleed off compression and make a flathead a bear to start and not want to run

[MSBiker 45]

Compression feels really good. I don't believe this is the problem. 

[Sailman 1,134]

Best way to diagnose your problem is by removing each possible weak link. Get the spray bottle with gas in it first and if it still doesn't run you have eliminated the no fuel option. Get the inline spark tester and if that checks out ok you eliminate the bad ignition option (plug, coil, etc). Then you need to dig deeper as suggested above with possible bad valves, blocked muffler, etc.

Just my $.02 worth. Good luck, those issues can be a stinker but sometimes its something simple like a bad ground wire, etc.

[RED-Z06 2,122]

Close the gap on the plug to 18thou to 20thou...it its weak spark this can show improvement by making it easier to jump the gap

[Handy Don 10,638]

On 1/1/2024 at 10:36 PM, MSBiker said:

* New carb set to 1 1/2 turns on idle and power. Old carb cleaned and set to the same 

 

FWIW, I’ve learned that many aftermarket carbs do not have the same threading on their needle valves as the OEM carbs so the “1-½ turns” may not apply. I always advise folks installing one of these to NOT TOUCH the needle valves during installation until AFTER trying to start the engine. If you cannot resist touching, AT LEAST, count the turns to gently close it so you’ll be able to restore it to its own “factory” setting later. Surprisingly, they often are good right out of the box and need only minor tweaking on a warmed up engine. 

My experience is with B&S, Tecumseh, Echo, Stihl, and Craftsman (Kawasaki) mostly.

Edited January 7 by Handy Don

[MSBiker 45]

19 minutes ago, Handy Don said:

FWIW, I’ve learned that many aftermarket carbs do not have the same threading on their needle valves as the OEM carbs so the “1-½ turns” may not apply. I always advise folks installing on of these to NOT TOUCH the needle valves during installation until AFTER trying to start the engine. If you cannot resist touching, AT LEAST, count the turns to gently close it so you’ll be able to restore it to its own “factory” setting later. Surprisingly, they often are good right out of the box and need only minor tweaking on a warmed up engine. 

My experience is with B&S, Tecumseh, Echo, Stihl, and Craftsman (Kawasaki) mostly.

Darn, did the turn the needle to "x" before trying to start. Did not count the turns. The interesting thing is that I cleaned up the old carb l, adjusted it the same, and had the exact same issues. Have to think about this a bit.

[kpinnc 10,773]

On 1/5/2024 at 9:21 AM, Sailman said:

Best way to diagnose your problem is by removing each possible weak link.

 

Agreed. Put a Kohler small block on it. Problem solved. 

 

But seriously, Teccy carbs can be a bear. If someone ever ran ethanol gas in it, probably even more difficult to revive. That being said, Teccys still have a loyal following. Folks who like them really like them. 

[Handy Don 10,638]

If you have access to an ultrasonic cleaner....

[Handy Don 10,638]

On 1/10/2024 at 10:18 AM, Handy Don said:

If you have access to an ultrasonic cleaner....

Any further luck on the Lawn Ranger?

With similar results for two carbs, if you haven’t checked the rest of the fuel supply now would be good. The LRs had a petcock on the tank with a build in strainer screen that sticks up inside the tank. If that is mushed/mangled/clogged it’ll severely constrain the fuel flow. Since the H60 is gravity fed (no fuel pump) any constriction in the plumbing can cause interrupted fuel flow.

[Horsin'round 5]

Have you checked the points yet? I was struggling with the h60 on my L-156 until I replaced the points and condenser with genuine tecumseh parts. It runs great now. 

[MSBiker 45]

4 hours ago, Horsin'round said:

Have you checked the points yet? I was struggling with the h60 on my L-156 until I replaced the points and condenser with genuine tecumseh parts. It runs great now. 

Not yet, been working on other projects. I will look into this. Thanks. 

[MSBiker 45]

Well started working on the Wheel Horse again. Had some luck with getting it started. But, it will not reliably start and it will not run for very long. Got it to run consistently one time and I was able to grossly adjust the carb to make it run smooth. Thought I had it but tried to start it again and it still won't start reliably or if it does start it will not run for a full minute. 

Pulled the tank and cleaned it, it wasn't horrible. I'm going to red coat it tomorrow just to add a layer of protection. Cleaned the pickup screen, it looks good. Added a new fuel line and carb. So fuel system should be good.

Orderd magneto parts and while I was disassembling the fan shroud to get at the flywheel/fan I found this little jewel, a thing named Power Start, Power Lawnmower (picture below) that is connected into the ignition. When I pulled it, it had a small crack in the back and looked like the plastic case is bulged a little bit. Not sure what it is (I can guess), but wondering if you folks knew what it is and if it can be causing my issues?

Also if I replace the coil on the mag what is the air gap between the coil and the magnets?

I am assuming that the pull start H60 on this tractor didn't have a battery (no lights, no electric start), just ran on the mag. Correct me if I'm wrong.

 

[Handy Don 10,638]

Mystery to me!

The HH60 in my LR is mag only for ignition but it does have a stator, diodes, and a battery for electric starter.

[MSBiker 45]

I think it is a points eliminator. I have one that I will try tomorrow. If it works maybe I won't install the tune up kit I got. I keep hearing about problems getting this Tecumseh H60 engine timed correctly.  If you have a procedure for timing this engine I would appreciate the info.

[RED-Z06 2,122]

21 minutes ago, MSBiker said:

I think it is a points eliminator. I have one that I will try tomorrow. If it works maybe I won't install the tune up kit I got. I keep hearing about problems getting this Tecumseh H60 engine timed correctly.  If you have a procedure for timing this engine I would appreciate the info.

My method for points Tecumsehs is to pull the head, head gasket, put a dime on the piston, drop it down, put the head back on with no gasket. Rotate the engine clockwise until it stops.  Pull the flywheel, set the points to 0.020", then using a buzz box or continuity tester on the points, loosen the coil bracket bolts and make sure the points are in contact (continuity) then slowly rotate the coil bracket until they break continuity..tighten the bracket.  The crack should, this whole time, be up against that dime.  Now remove the head, the dime, put the gasket back on.

 

I had an HH70 that i fought for days, wouldn't start right, wouldn't idle, wouldn't rev clean..my old boss showed me that trick and bam, 1 pull...tuned it in, ran like a top.

[MSBiker 45]

Interesting. Stupid engineer here, I wonder how he figured a dime was correct? I might have to try this. Seems weird but makes some sense. Thanks.

[RED-Z06 2,122]

1 hour ago, MSBiker said:

Interesting. Stupid engineer here, I wonder how he figured a dime was correct? I might have to try this. Seems weird but makes some sense. Thanks.

I think its just that the piston needs to be down the hole coming up before top dead center and a dime is a pretty consistent thickness (0.053") and a dime gets you there.

 

Its like doing valves on a Briggs ohv engine, briggs has a whole method that involves putting a dowel down the plug hole and pushing the piston down past compression stroke 1/4" or something..to ensure both valves are on the base circle and off the compression release.  The quick way...if 1 valve is down; the opposite valve is definitely on the base of the lobe...set that valve, then rotate until that ones down and do the other....there's usually an uncomplicated method that gets you do the same end as the technical method.