Testing a carburator...

I'm trying to get to the bottom of lean issues. So now the time has come to test the carbs. I know how to perform a the pop off test and look for the needle to seat properly.

Are there any OTHER pressure/vacuum test to perform while i'm at it? I wanna rule out all issues.
 

Quinc

Buy a Superjet
Location
California
You might take them all the way apart and let them soak in chemdip for a few hours to make sure they are clean inside and out.
 

Vumad

Super Hero, with a cape!
Location
St. Pete, FL
I'm trying to get to the bottom of lean issues. So now the time has come to test the carbs. I know how to perform a the pop off test and look for the needle to seat properly.

Are there any OTHER pressure/vacuum test to perform while i'm at it? I wanna rule out all issues.

The popoff test makes sure the needle lets go crisply at the proper psi.

You also want to leak test it. Same as a popoff test but stop at 10 psi for 10 minutes. If it is leaking then you need to find the leak, usually around the fuel pump gaskets. Spray wd40 to isolate leaks.Put reusable zip ties on your tester so you don't have leaking from the fuel lines during the test. Corrosion, old gaskets and low quality gaskets such as Sbt rebuild kits cause leaks so the fuel pumps don't work right. jetmaniac sells replacements screw kits for the fuel pump that have Allen heads so you can torque better to prevent leaking without dealing with stripped Phillips.

I also make sure there are no leaks a few psi below the popoff, I just don't wait the full 10 minutes.
 
The popoff test makes sure the needle lets go crisply at the proper psi.

You also want to leak test it. Same as a popoff test but stop at 10 psi for 10 minutes. If it is leaking then you need to find the leak, usually around the fuel pump gaskets. Spray wd40 to isolate leaks.Put reusable zip ties on your tester so you don't have leaking from the fuel lines during the test. Corrosion, old gaskets and low quality gaskets such as Sbt rebuild kits cause leaks so the fuel pumps don't work right. jetmaniac sells replacements screw kits for the fuel pump that have Allen heads so you can torque better to prevent leaking without dealing with stripped Phillips.

I also make sure there are no leaks a few psi below the popoff, I just don't wait the full 10 minutes.

Thanx vumas thats just exactly what i needed! already sporting new allen head bolts on it and original mikuni gaskets =)
 

smoofers

Rockin' the SQUARE!!!!
Site Supporter
Location
Granbury, TX
The popoff test makes sure the needle lets go crisply at the proper psi.

You also want to leak test it. Same as a popoff test but stop at 10 psi for 10 minutes. If it is leaking then you need to find the leak, usually around the fuel pump gaskets. Spray wd40 to isolate leaks.Put reusable zip ties on your tester so you don't have leaking from the fuel lines during the test. Corrosion, old gaskets and low quality gaskets such as Sbt rebuild kits cause leaks so the fuel pumps don't work right. jetmaniac sells replacements screw kits for the fuel pump that have Allen heads so you can torque better to prevent leaking without dealing with stripped Phillips.

I also make sure there are no leaks a few psi below the popoff, I just don't wait the full 10 minutes.

This!

Leak test is one of the most important things to do on your carbs. I've learned the hard way by roasting a piston.

jones2012052.jpg
 
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