Pressure/Vac Test

[Butterbean 150]

What do you guys use to block off the carb side of Stihl saws for the leak test???

 

[Ozhoo]

A piece of rubber between the intake and carb. Use the impulse hose to test.

 

[hotshot]

Which Stihl saw are you P&V testing?

If carb box is off, just use spare intake boots & epoxy glued in lab stoppers...with red neck looking tywraps added, if needed.

Test port is via the spark plug hole or impulse.

 

[2stroker]

I've used Ozhoo's method and it has worked well.
I'm not a fan of replacing the boot with a modified one as I want to check the boot that will be used on the running saw and it's seal to the cylinder for leaks.
A lot of carbs have the same hole spacing and I've used the Stihl Carb block off plate and have made several similar ones to do the job.
I've used an aluminium siding nail to plug an impluse line when needed.
2stroker

 

[TheTone]

I've used Ozhoo's method and it has worked well.
I'm not a fan of replacing the boot with a modified one as I want to check the boot that will be used on the running saw and it's seal to the cylinder for leaks.
A lot of carbs have the same hole spacing and I've used the Stihl Carb block off plate and have made several similar ones to do the job.
I've used an aluminium siding nail to plug an impluse line when needed.
2stroker

I also like doing P&V tests with impulse line and intake boot in place. I got a set of graduated rubber stoppers from The Widget Co. to plug the boot. I use Dow-Corning silicone high vacuum grease (from my organic chemist days - but I guess any thick grease would work) to seal the stopper where it meets the outer (smooth) edge of the boot. I cap off the exhaust port with either a homemade plate and a strip of neoprene or by using the muffler as the block off plate. This way you know the intake boot, impulse line, and seals are good if it passes the test. If possible, I measure P&V through the impulse line, with the spark plug in place.

 

[HarleyT]

I used to use old junk carbs that I siliconed a nipple in the throat, before I got a set of carb blockoff tools from Stihl.