air in fuel line

[sdiet]

My engine dies at idle (25 hp johnson, 1971), I had the cover off and noticed that at idle when the enginge would start to die, there was air chugging through the clear plastic fuel line, think it was the one that runs from the fuel pump. Is this most likely a bad fuel line (loose, or cracked), or would the fuel pump suck air, or is it normal to have some air in the line at idle?

 

[jim dozier]

Re: air in fuel line

Most likely you have a tear in the fuel pump diaphragm or a leak at the hose connection. It should be simple and inexpensive to rebuild the fuel pump. Sometimes you can tell if its leaking by loosening the bolts/screws that attach the pump to the block and then pumping the fuel bulb. If fuel comes out the back you have a bad diaphragm.

 

[sdiet]

Re: air in fuel line

I pulled the fuel pump, and primed the bulb. could not detect any leak. But I ran the motor again, and at idle, I noticed that there was gas in the line that runs from a big port on the side of the engine (above the fuel pump), and a smaller port on the front of the engine (back up behind the carburetor). I suspect this line provides the pressure difference to operate the fuel pump and should not be getting gas in it. Is this correct? I've ordered a fuel pump kit.

 

[stairliftoheaven]

Re: air in fuel line

If thats the vacuum line your referring to; there definitely shouldnt be fuel in it. Agree with jimd, theres a problem in the fuel pump, but thats not hard to rectify with a rebuild kit<br />good luck

 

[sdiet]

Re: air in fuel line

Thanks, I believe it is the vacuum line, the only other clear line about the same size is the one that runs from the fuel pump to the carb. Is the fuel pump rebuild very difficult?

 

[stairliftoheaven]

Re: air in fuel line

fuel pump rebuild staright forward, just watch out when u take it a part as springs fly out if your not careful. note carefully where springs are located for reassembly purposes.