Got another stubborn one.. Stihl 017

[Bob Hedgecutter]

Compression tests only test the combustion chamber above the piston- not going to tell you if excessive air is being pulled into that mix through the crankcase proper and up through the transfers.

 

[stihltech]

I find it odd that so many do not feel the need to vacuum and pressure test on a saw with age. First place I go in the shop. At least 75% will have it.

 

[Jeff Lary]

Interesting, following along.
Do you have a spark tester which you can extend the gap the spark has to jump to see just how good the spark really is? I had a saw one time that had spark but wouldn't fire added fuel, so I took a good running saw and swapped in the known good plug, and it fired.
Also, I have a messed-up shoulder so holding a saw upside down while I crank the heck out of it is very hard for me, but I have done that. My latest adventure doing this I removed the muffler and the plug and let the saw "air out" for a couple days. Fired right up next time I tried it. Though this is likely not your issue it is just what I did to a severely flooded saw recently. Good luck with the saw. JeffinMaine

 

[a. palmer jr.]

Compression tests only test the combustion chamber above the piston- not going to tell you if excessive air is being pulled into that mix through the crankcase proper and up through the transfers.

It would have to be a big leak for it not to fire at all if you put fuel in spark plug hole.

 

[a. palmer jr.]

Interesting, following along.
Do you have a spark tester which you can extend the gap the spark has to jump to see just how good the spark really is? I had a saw one time that had spark but wouldn't fire added fuel, so I took a good running saw and swapped in the known good plug, and it fired.
Also, I have a messed-up shoulder so holding a saw upside down while I crank the heck out of it is very hard for me, but I have done that. My latest adventure doing this I removed the muffler and the plug and let the saw "air out" for a couple days. Fired right up next time I tried it. Though this is likely not your issue it is just what I did to a severely flooded saw recently. Good luck with the saw. JeffinMaine

I had a spark tester, knew exactly where it was, went there and it was gone. Another mystery of moving. I think maybe wife's getting rid of my tools, one at a time. In lieu of testing I have several spark plugs and probably can find a module around here someplace. I have a spare flywheel also.

 

[a. palmer jr.]

I find it odd that so many do not feel the need to vacuum and pressure test on a saw with age. First place I go in the shop. At least 75% will have it.

It's been brought up. Maybe in warmer weather when I can spend more time in the garage I'll get a little more involved. Right now I'm just going out there to feed the cat and I tinker a bit while he's having his breakfast, then I go back in the house and take him with me. I don't usually spend more than a half hour on the saws.

 

[Bob Hedgecutter]

It would have to be a big leak for it not to fire at all if you put fuel in spark plug hole.

Really?
A loose engine pan is a pretty good leak.