036 Pro won't hold vacuum?

[stoolie10]

I replaced the top end, installed new base gasket, & blocked off muffler/intake with rubber. I'm using my mighty vac at impulse. (no vacuum will hold) I also checked spark plug for tightness & replaced decomp with an optional plug.

 

[Big_Wood]

mix some dish soup and water in a spray bottle, hook up compressor as 5-10psi to impulse. spray saw down and watch for bubbles. that's show you your leak. it is often the flywheel side crank seal on these saws. i did the deals in my beater 260 when i got it last year because it did the same thing. fixed it up mint. rebuilt an 036 that had the same leaky flywheel side seal about a year ago as well. it's a common problem.

 

[Milkman31]

I would put the saw under water and use psi to find the leak.

 

[fordf150]

I have had all of mine leak on the pto side seal or between the pto side bearing and case.

 

[stoolie10]

I just find it odd that this saw was recently running less than 2 weeks ago, before a cir clip ruined my top end. Maybe that is why it never seemed like it had a lot of compression.

 

[lone wolf]

It wont hold vac or pressure?

 

[stoolie10]

I have only tried vacuum, so far. I will try pressure test tomorrow.

 

[AKDoug]

I was working on an 034 the other day that would hold pressure but not vacuum. This happens often because pressure will push the seals out, sealing them. So, to chase which seal it was I laid the saw flat on the clutch side and dribble some mixed gas on the flywheel side seal. When I applied vacuum you could watch it suck in the mix. I replaced that seal and still had a slow leak. Flipped the saw over to put the clutch side up and tested the clutch side seal. Same issue when vacuum was applied.

 

[stoolie10]

I am not sure about replacing seals myself. The stihl tool seems like the best choice. (Seals are so small)

 

[stoolie10]

I checked both seals for leaks, no bubbles? I'm a little concerned about dunking saw in water. hmmm?

 

[redfin]

Air pressure holds the water out of the case.

 

[woodeneye]

I had to resort to dunking my 026 in water. I just made sure I had positive pressure from my compressor on the saw to make sure it was pushing air out and not sucking any water in as I baptized it. Let dry overnight and everything went back together fine.

 

[lone wolf]

I checked both seals for leaks, no bubbles? I'm a little concerned about dunking saw in water. hmmm?

Am I right to assume it is in FACT a vac leak? did it pass pressure and not vac ? If that is the case I know what to do.

 

[HarleyT]

If you are using a hand pump, you will have to pump a lot more to build up a noticeable reading, not the same as a pressure test.

 

[stoolie10]

I just used my compressor on the lowest possible setting, not sure of exact pressure? Couldn't find any obvious leaks.

 

[lone wolf]

I just used my compressor on the lowest possible setting, not sure of exact pressure? Couldn't find any obvious leaks.

So no leaks with pressure but Vac fails is that correct?

 

[HarleyT]

Compressor? Mighty Vac? Are we all talking about the same things? You are not doing a proper pressure test? Then you might as well forget the vac test......

I just find it odd that this saw was recently running less than 2 weeks ago, before a cir clip ruined my top end. Maybe that is why it never seemed like it had a lot of compression.

Well, this is totally different scene!!!! Why don't you start from the beginning? Instead of futzing questions that have nothing to do with your problem?

 

[HarleyT]

You bought this saw from someone?

 

[stoolie10]

That seems to be the story...so far. I am wondering if my base gasket is not sealed up tight? I just hand tightened bolts to base, wondering if the used cylinder has a small flaw. This saw rerunning prior to cir clip release in old cylinder.

 

[HarleyT]

It ran great until it died a nasty death?