Most here will understand this but I feel somewhat obligated to reiterate the importance of vacuum/pressure testing small two stroke equipment. Just sold a top end job on a mtronic 362. Don’t throw parts at anything before you know how it failed.
Importance of vacuum/pressure testing
- Thread starter ballisticdoughnut
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Not just small two strokes. All two strokes.
You would be surprised at the numbers of guys who seize motors several times because they didn't determine the original failure mode.
You would be surprised at the numbers of guys who seize motors several times because they didn't determine the original failure mode.
Somebody got a Stihl dealer tool box?
yes sir.
It is a guarantee that the problem will not bee a leak in the bottom end.
Yes it is nice to have a Stihl tool kit, but it is not necessary.
Many posts here and you tube on how to to it. Yes, you can buy a Harbor Freight pressure and vacuum tester and do the same thing.
And I goofed up. VACUUM and pressure, in that order.
Yes it is nice to have a Stihl tool kit, but it is not necessary.
Many posts here and you tube on how to to it. Yes, you can buy a Harbor Freight pressure and vacuum tester and do the same thing.
And I goofed up. VACUUM and pressure, in that order.
I have the stihl dealer tool box. Use the vacuum/pressure tester to test fuel lines and impulse lines is about all.
I know I am a contrarian. But , if you can't hear that a saw has a leak running it you may need to do something else.
Starter fluid with a nozzle to find it.
I know I am a contrarian. But , if you can't hear that a saw has a leak running it you may need to do something else.
Starter fluid with a nozzle to find it.
Map gas works too.
A vac/pressure test before re-building a carb is a good thing to do when testing a chainsaw. If vac/pressure test is bad, a good carb will also appear to be bad also.
barfer
I like chopping wood
Propane also… get it close… if it revs up you found the leak…
But +1 with everyone above who said you don’t need a special Stihl proprietary tool. Virtually any auto parts shop will have a compression checker that connects to the spark plug hole. Those vacuum/pressure pumps with gauge are sold by everyone from snap on to mighty-vac or cheapo harbor freight.
The compression tester is a tool that is inexpensive and I think everyone should have because even without “problems” to diagnose measuring your compression and recording it over time will tell you how your rings are wearing… how much life is left in your motor… and it really is just as easy as changing a spark plug (bwalker I know you’re thinking about sawdust falling in there right now
)Great post OP!
I've never done one yet, so I don't know. Why do them in that order?
I don’t, though it works either way.
I always test w/ pressure first to use soap spray bubbles to quickly find it/them & to keep more crap from being sucked inside the saw.
Make sure it holds 8-10 psig all day. Rotate the crank a few times if you want to. Stick an oiled up round toothpick in the seal to shaft contact area & see if the lip rebounds if you want to. Hard & old seals will keep leaking…
Then pull a 14”Hg vacuum, again should hold for hours and if it won’t hold it’s got a bad seal(s)! Squirt some light 3-1 machine oil or baby oil around the shaft to see if it pulls it in during the vacuum decay failure.
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