18 HP Briggs - Fuel Starvation

[Kevin]

Hi,

I have to prime my engine to get it to go. It will run at idle with choke on; once warmed up it idles with choke off. If I try to rev up, it starves and dies. I have checked the fuel filter, tank, and see no problem. I also checked the fuel pump (dia. type on front of carb), and it looks ok -- didn't see any problems with the diaphragm or springs. I don't see the typical fuel in the inlet chamber that you normally see. There is also very little fuel visible in the filter when it is running. I also pulled the vacuum line off the bottom of the fuel filter with it running. It kept running, and I could feel some vacuum when I put my finger over the end of the line (BTW, how much vacuum should it have?). Definitely no fuel line clogs.

I shut it off last year, but did put stabil in it and ran for several minutes before shutting it off.

Any ideas here?

TIA KR

[Joe Bobst]

See if it runs with the air filter off. If it does, replace it or clean it. HTH

Joe

[DR, Bob]

2 things check if your choke is properly adjusted remove airfilter put chock on and look to see if it closes the venturi of the carb all the way. If it dies when you go from idel to high speed (when engine is at operating temp) the low speed circuit is too lean and is either misadjusted or has a pluged circuit in the carb.

[Kevin]

Thanks, DR, Bob...

Choke appears to work properly. Engine dies right-away when throttling up. No adjustments were done on this tractor, but just in case, where and how do you adjust the low speed circuit? Would putting in a carb rebuild kit do the trick?

Lastly, what is the proper vacuum for the fuel pump vacuum line? I do get some suction, but wonder if there is enough. I hate to tear into the carb just to find out later that fuel pump suction line didn't have enough vacuum.

KR

[m Ransley]

Sounds like possibly a stuck float or clogged jet. Dissasemble and clean carb.

[Kevin]

Does this require any special tools?

[m Ransley]

Special tools no , but real carb cleaner to soak the carb costs a bit, sometimes you can see the piece of dirt, do you have an external fuel filter, It suprises me that allot of good motors come without them

[Kevin]

There is a fuel filter in the line, but I'll probably replace it when I clean the carb. Thanks for all the info... KR

[Stormin Mormon]

One thing a lot of folks don't check is the gasket between the carb and the side of the engine. If this gasket is loose, or leaky, it makes it nearly impossible to start. (Needs ether or gas in the air intake to start).

[evolie]

Does carb cleaner help with low carb diets too?