Help diagnose fuel delivery problem - Stihl 051

[cmetalbend]

OK I just went back and looked again (skimmed over it the first time, sorry) and noticed that your shrader valve is in the middle of the hose on your compression gauge. The length of hose between the valve and the cylinder is causing you to get a lower reading than it should be, by how much I don't know but your gauge is not going to give you and accurate pressure reading on a saw. You really need to get a gauge with the valve at the end of the hose like Andy said. Your compression is likely enough to get the saw running right now, probably not gonna have the giddy up it should with fresh rings but it should run. Most important thing right now is to find that air leak. Get it fixed and you can worry about compression then. Run your pressure/vacuum test again and make sure the decomp valve is not pushed in. I've actually done that one myself, push in the valve pull on the saw, no start, tear it down to run pressure/vacuum test, nothing, realize you left the decomp button down, kick self in the arse, run test again everything fine you get the idea. Good luck

Another dumb move I've heard about was not having the spark plug in, while vac/pressure testing.

 

[OneStaple]

I just ran the compression test again and got 105 psi this time. It seems like even if that's reading a bit lower than the actual value due to the placement of the schrader valve, it's still lower than it should be. I'm trying to get something in the 150 psi range, right?

I'll try to do the vacuum/pressure testing tonight and let you know the results. I'm also getting ready to leave in a couple days to go out of the country for a few weeks, so that's getting balanced with fixing the chainsaw (although I really want to get it working before I go, or at least know what needs fixing when I get back).

How often does something like the decompression valve go bad? That'd nicely explain both problems, I think. But given the way the world works, it probably won't be nearly that easy.

--Tyler