Mityvac pressure test on old saws

[happysaws]

Has anybody ever used a Mityvac on an old saw that uses reed plates?
I would like to vacuum/pressure test the crankcase on a few old saws, but I'm not sure how to do it, because the old saws use reed plates. There's no barb to connect a hose to for putting pressure/ vacuum in the crankcase.

If anybody can shed some light on this subject, I would appreciate it!

(Sorry if this topic has already been discussed, I couldn't find anything about it.)

 

[hotshot]

Just use a spark plug adapter to 'tap' into the case & pull it down to 15"Hg.
Flip the lever & pump it up to 8 psig.

Husqvarna makes a great tool #503844002, used it on dozens of reed valved saws, not an issue for vacuum or pressure.

 

[brandonstc6]

I just bought one myself and I am working on my procedure. I have a rubber inner tube from a car tire. I used a piece of it under the muffler to block off the exhaust. I am going to try a piece under the carburetor and the spark plug adapter mentioned above. I didn't have much luck with a wood plug in the intake boot.


Sent from my iPhone using Tapatalk

 

[hotshot]

Yep, blinding ports & impulse driven oil pumps is always the innovative part, but finding the leak is where you'll usually get your butt kicked.

 

[happysaws]

Just use a spark plug adapter to 'tap' into the case & pull it down to 15"Hg.
Flip the lever & pump it up to 8 psig.

Okay, but wont putting pressure/vacuum into the engine through the spark plug hole only check the leakdown of the piston rings?

If I move the piston so the intake ports are exposed, thus letting pressure into the crankcase, the exhaust port is also open.

Thanks for the help!

Sent from my LGLS775 using Tapatalk

 

[happysaws]

Okay, but wont putting pressure/vacuum into the engine through the spark plug hole only check the leakdown of the piston rings?

If I move the piston so the intake ports are exposed, thus letting pressure into the crankcase, the exhaust port is also open.

Thanks for the help!

Sent from my LGLS775 using Tapatalk

Oops, didn't see brandonstc6's post about covering the exhaust port with rubber. My apologies.
Makes more sense now. Thanks again!

 

[happysaws]

...Husqvarna makes a great tool #503844002...

Thanks for the PN, I was unable to find anything like this.

 

[hotshot]

YW, there's sponsors on this site that sells them too!

 

[happysaws]

YW, there's sponsors on this site that sells them too!

Shows how hard I actually looked for one...

 

[s sidewall]

$7.50 online

Steve

 

[grizz55chev]

Oops, didn't see brandonstc6's post about covering the exhaust port with rubber. My apologies.
Makes more sense now. Thanks again!

You also need to block between the carb and the reed valves.

 

[happysaws]

You also need to block between the carb and the reed valves.

Yep I got it. Thanks to all for helping!