Reply To: JW 14 compression numbers?

[Don]

Yeah, you might want to try the carb from the other engine to see if the 14 runs the same. 60PSI is certainly marginal for one of these engines, but it is even on both cylinders. I have one lightwin with fairly low, but uneven compression numbers, but even this poor ol wore out engine idles “pretty good”. It will idle down but kinda loses steam after a minute or so, then fades away and dies…
So, I’m thinking there is something else wrong with yours if it won’t idle at all…..
Does it look like someone has had the powerhead apart.
Has the intake manifold been off? If so, perhaps they have the wrong intake gasket in place behind the reeds.
All of this reminds me how important it is to check and trust the basics. Have spent a few days trying to help out a buddy at his shop. One customer has two beautiful older engines….A 1976 6hp that looks “almost new”, and a 1980 15hp that looks so new I was afraid of scratching it up. The 6hp wouldn’t pump, so Gary had me replace the water pump, but it turned out the thermostat bypass was plugged up…Got it going, but the starter was kind of funky, and it didn’t idle like a 6hp should…Monkeyed around with it for a bit, then decided I would bring in a known good carb from home….As my luck goes, the starter spring popped out when I attempted to slide it over removing the carb…Got the starter to work well enough to start it, but it still ran the same….So, decided to put the original carb back on. Decided to replace the starter rope, the old one was cut short. Still couldn’t get the starter to work properly. Finally had to replace the spring cuz someone had bunged it up before me, that person had been inside the carb also. So, finally got the rewind working properly, and thought at least the guy can use the engine even though it didn’t idle properly….Finally, I decided to put a compression gage on it, 60/90PSI….I could have saved alot of time if I did the basic compression test first…But, I was fooled by how “new” the engine looked. Don’t know what Gary’s customer will decide to do now, but at least the engine is usable. No water in the cylinders or signs of overheat, so am guessing there are stuck rings or internal problems.
In your case, compression is even, and the gage is always suspect when checking compression on these tiny combustion chambers. Just reread your post, does the 14 idle at all, or does it just cut out when you attempt to idle it down. It seems like you have had the head off and didn’t see any obvious issues, correct? Perhaps you should attempt to remove the exhaust cover, if the screws will come loose, don’t mess with it if the screws are stuck. Maybe the rings are stuck, a good soaking with engine tuner might help. I am not afraid to rough up/deglaze the cylinder walls on these things with some fine emery/crocus cloth…Crude yes, but this will remove the glaze and might help the rings to seal…Just blow out the dust with compressed air and clean it up with the carb cleaner spray.