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OK, I am just looking for some possible help. I have been an OPE mechanic for nearly 50 years. I can't remember only one other engine that I couldn't make run, unless it was totally worn out or something. This one has me pretty stumped. It is a 3.5 Hp H35 on a small generator. I have known this engine for several years, and worked on it (ignition and carb work) Many times, as the owner leaves it outside often. It was in a flood this spring. As were several other engines of his. I got them all cleaned up and running without a problem. This one I put in new points, but not the condenser. It has good blue spark that will jump my small spark tester with a 150 thousands gap, and sometimes the tester with .250 gap. Knowing this engine for a long time, that is all the better the spark has ever been. The compression is excellent. The carburetor was trashed, so bought a new one on line. I even took it apart and made sure all the passages etc were open . Also new spark plug. Now- the best I can get is maybe 2 pops in a row. But not consistintly. I am ready to give up. Makes an old man want to pull out what hair he has left.

replace condenser & get back to us, thanks, Mark

forget condenser since you have good spark. fresh gas, fresh air filter, good spark & compression, sounds like fuel issue.

http://www.barrettsmallengine.com/manual/tecumsehlheadmanual.pdf

check out above manual troubleshooting section, see page 14

So, even though it has good spark you believe the condenser could be the problem? I have thought of that, but didn't think it could be. But then, it obviously is something that I don't think it could be. I always say, if everything checks good, but it doesn't work it is something that checks good, but isn't.

Have you checked timing....flywheel key?

MowLife said:

Have you checked timing....flywheel key?

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I'm with mowlife, check the flywheel key. It should make a perfect square in the key way.

I mechanic-ed half my life before I discovered compression and timing could be checked simultaneously on these little engines with no tools except your eyes, finger/thumb and ears.

If compression is up to snuff and the spark plug shows good spark when grounded to the head, when the engine is cranked, you'll see spark at the exact same time your finger or thumb is blown from the plug hole.

Usually requires a helper to crank. If a youngster is the cranker, trade duties with him/her and that youngster will learn something they will never forget.

See if you can get it flooded, plug wet with gas. If if won't hit and the plug stays dry it's a carb problem. Still. Water in bottom of float bowl?

SeniorCitizen said:

Usually requires a helper to crank. If a youngster is the cranker, trade duties with him/her and that youngster will learn something they will never forget.

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Yep, don't help Papaw work on an engine. LOL.

mechanic mark said:

replace condenser & get back to us, thanks, Mark

forget condenser since you have good spark. fresh gas, fresh air filter, good spark & compression, sounds like fuel issue.

http://www.barrettsmallengine.com/manual/tecumsehlheadmanual.pdf

check out above manual troubleshooting section, see page 14

Click to expand...

UPDATE. -- Since the spark was ok, but not great, I went into the ignition again. For some weird reason it seemed that the points weren't even quite going shut. I know it should not have even had ANY spark, but it did. I replaced the points and condenser, put it back together and it started on the second pull. OK, so now I am back to only one engine I couldn't make run, and that was about the second one I worked on about 50 years ago.