Mity Vac problems

[david newbie]

I am working on a 394 and discovered fuel is gushing out of the top of the walbro carb as soon as I put fuel in the tank. Thought I would pressure test the carb, but my mity vac is acting weird. It will build up vacuum but not pressure. I tested it several times(the tool) by blocking off the end of the tube/. Do these vacs require any lubrication? Tool is not all that old and has not seen much use

 

[Mad Professor]

Carb most likely has a problem with the metering side. Needle/seat/lever.

Can't help with the Mity vac

 

[Chevboy0167]

Which model of vac/pump do you have?

I see there are service kits....




https://www.skf.com/mityvac/products/hand-vacuum-pressure-pumps

 

[david newbie]

Which model of vac/pump do you have?

I see there are service kits....

View attachment 1227834


https://www.skf.com/mityvac/products/hand-vacuum-pressure-pumps

I’ll have to look for a number. Thanks

 

[dwaugh]

I do remember on my old Mighty-vac there were some parts that I needed to occasionally clean and lubricate. I think I remember some O-rings and sealing surfaces that I put silicone faucet type grease on. Check the mechanism that makes it go from pressure to vac. That was the cheap all plastic one, I have a new metal one that I have not used yet.

 

[guym3]

Look on youtube at vintage engine repairs where Tom has done an excellent video on stripping down and servicing a mityvac.

 

[Vintage Engine Repairs]

Look on youtube at vintage engine repairs where Tom has done an excellent video on stripping down and servicing a mityvac.

Thanks for the shoutout!

 

[guym3]

That's ok. I hadn't realised until I serviced mine, how knackered it was. Works much better now.

 

[david newbie]

Look on youtube at vintage engine repairs where Tom has done an excellent video on stripping down and servicing a mityvac.

Very helpful! Thank you!