Need detailed instructions-vacuum test 361 crankcase

[kspakland]

MS361 won't start, won't draw gas from the tank.
I did a search on the site but ended up more confused after the search, I need to learn how to vacuum test the crankcase and impulse line.
I have a mityvac hand vacuum pump with gauge, and I might be able to fabricate some things to use for the test if needed, if I have enough detailed instructions how to perform the tests.
Many thanks in advance!!!
Kev

 

[SteveSr]

There are plenty of threads on here. Start reading. The basic idea is to block the known (intentional) leaks like ports and then apply pressure through either the impulse port or with a spark plug adapter. A big bucket of water to dunk the saw will instantly show you where the leaks are. The bubbles would be your first clue.

 

[stihl86]

I can’t say no because I’ve used it. But the “Dunk Test” is a last resort.

 

[SteveSr]

I can’t say no because I’ve used it. But the “Dunk Test” is a last resort.

The dunk test is good after you have ruled out all of the usual suspects. Found a cracked pan in a mag rotted 025 this way.

 

[pioneerguy600]

Pressure is required , not vac for the water test.

 

[stihl86]

Pressure is required , not vac for the water test.

Yes. Very good point for someone unfamiliar with a test as high tech as the “Dunk Test”
Or someone would be looking for a leak in their bucket wondering where all the water is going.

 

[SteveSr]

Pressure is required , not vac for the water test.

Well, looking for bubbles would be a good indication, at least for me, to use pressure. I think I may have said same in a earlier post.

 

[pioneerguy600]

Yes. Very good point for someone unfamiliar with a test as high tech as the “Dunk Test”
Or someone would be looking for a leak in their bucket wondering where all the water is going.

I actually know of a case where water was drawn into a crankcase inadvertently...LOL