Carb rebuild problems

[redunshee]

Currently rebuilding three Walbro HDB carbs with I believe proper kit #(K10-HDB). Problem is when running a pressure test(7 lbs. in water) all three are leaking from the diaphragm cover(opposite side of the metering needle cover). I'm lost as to the problem as I've never had this problem before and find it hard to believe that these three carbs are shot. I've switched repair parts and done all I can think of to fix this problem. Any ideas?

 

[Stihl051master]

Do you think it could be a problem with your test equipment? I also find it strange that all 3 carbs would be bad. I've rebuilt countless diaphragm style carbs, and never had that problem either. Do you have a saw available to test run one of the carbs on?

 

[OilHead]

Test it this way & see if it passes the test. - - - http://www.aerocorsair.com/id28.htm

 

[RED-85-Z51]

Currently rebuilding three Walbro HDB carbs with I believe proper kit #(K10-HDB). Problem is when running a pressure test(7 lbs. in water) all three are leaking from the diaphragm cover(opposite side of the metering needle cover). I'm lost as to the problem as I've never had this problem before and find it hard to believe that these three carbs are shot. I've switched repair parts and done all I can think of to fix this problem. Any ideas?

So it's leaking around the pump side, not the metring side, correct?

are you positive you removed all traces of old gasket from the covers, the gaskets usually leave little bits stuck to the metal, takes a while but a stiff brass brush will get them off, just go easy.

It's all assembled in the right order, with the check valve/pump skin to the carb body, and the gasket to the cover?

 

[Lakeside53]

guys.... a carb assembled with dry gaskets often does not seal....

If you want to go a pressure test before running, you need to assemble the carb wet - dip everything in gas-mix...

 

[redunshee]

guys.... a carb assembled with dry gaskets often does not seal....

If you want to go a pressure test before running, you need to assemble the carb wet - dip everything in gas-mix...

A HA! Have to admit in my prior rebuilds I did not pressure test. New tester so I thought I'd check it out before running saw. Thanks. Hopefully you've hit the nail on the head.

 

[redunshee]

Do you think it could be a problem with your test equipment? I also find it strange that all 3 carbs would be bad. I've rebuilt countless diaphragm style carbs, and never had that problem either. Do you have a saw available to test run one of the carbs on?

I think LakeSide hit upon the problem. Dry gaskets etc. often leak. You were right though about running saw. Wets gaskets and hopefully won't leek.

 

[redunshee]

Test it this way & see if it passes the test. - - - http://www.aerocorsair.com/id28.htm

Thanks. Site and LakeSide hit upon my error. Did not wet inside of carb. etc

 

[redunshee]

So it's leaking around the pump side, not the metring side, correct?

are you positive you removed all traces of old gasket from the covers, the gaskets usually leave little bits stuck to the metal, takes a while but a stiff brass brush will get them off, just go easy.

It's all assembled in the right order, with the check valve/pump skin to the carb body, and the gasket to the cover?

See Lake Sides thought. Has to be problem. By the way I see you have a wizard/ Poulan. I know Sears and Skil had Poulan made saws(have too many). Didn't know about Wizard(Western Auto???). Are there any others out there?

 

[scottr]

See Lake Sides thought. Has to be problem. By the way I see you have a wizard/ Poulan. I know Sears and Skil had Poulan made saws(have too many). Didn't know about Wizard(Western Auto???). Are there any others out there?

Dayton sold a rebadged Poulan and I recently saw a Husqvarna that was a rebadged Poulan XX.