Air leak through impulse inlet on carb...

[Freudianfloyd]

I am slowly getting this Craftsman 2.0 dumpster find up and running. It is having some starting issues and since I recently picked up a Mityvac 8500 I am actually trying to diagnose it correctly.

I just put a new piston and ring in it. Cleaned up the cylinder, new gaskets throughout.

Gets good spark, did work on the reed valve as it wasnt sealing, and rebuilt the carb. Somehow it still wont run.

Well I pressure tested the carb by putting a line on the fuel inlet side with about 10 psi and noticed a leak coming out where the impulse line would go in. I dont know if that is normal or not, but I cant imagine it is. Does that point to the needle valve not seating? If so, what is a typical fix for that considering it's a new needle. Is the carb junk?

Thanks guys

 

[Ozhoo]

Your fuel pump diaphragm is leaking/not sealing. If the saw hasn't been run in a while, you'll want to wet the fuel pump diaphragm (with mix) and retest.

 

[Freudianfloyd]

You're fuel pump diaphragm is leaking/not sealing. If the saw hasn't been run in a while, you'll want to wet the fuel pump diaphragm (with mix) and retest.

Ok, I will try that.

 

[alexcagle]

It's got to be really clean when you put it together. WD-40 sprayed in between the gaskets right before snugging it up usually cleans the microscopic dirt off, and helps it seal.
Remember, if it leaks crankcase pressure through the impulse port on the carb, then fuel will fill up the crankcase too, from the internal leak....

 

[s sidewall]

Once you get that going, just hope the oiling system is working.

Steve Sidwell

 

[alexcagle]

 

[s sidewall]

Lol[emoji28]

Steve Sidwell