Most likely it's the bowl nut. Drain the tank of gas and remove the nut on the bottom of the fuel bowl. You'll probably find gunk in one of the jets in the nut.

As Baymee said, the brass bowl nut is the main fuel jet.
There is a very small hole in the upper side of this nut
that supplies fuel to the engine. It's easily stopped up
and keeps this from happening. The primer must seal from
allowing air to enter, and dirt will follow. New primer
is Tec part# 36045A. Very easy to find at most Tecumseh
Dealer locations or on-line.

T-Man

WOW .... THANKS SO MUCH !!!

You saved me many more nights of frustration ..

Works like a charm now.

Thanks again!

Wow! 1 1/2 hours from time of the post to running again.

SCORE!

Hi-I have a similiar problem with my 6.75 Craftsman lawn mower and have replaced the float bowl twice now. It did fix the problem but it is happening again. I removed the bowl and cannot blow air into the gas inlet, this is what happen twice before. It appears the needle is sticking into the seat. Is it something I am doing or does it have to be replace again, any ideas would be great. The kit I ordered twice is 730637A. Thanks for the help.

If you are able to remove the carburetor, you should replace the needle and seat, NOT the float bowl. Otherwise, remove the needle and clean off the possible varnish on the tip and maybe you can use a Q-tip to clean the seat. Rinse the seat area thoroughly with cleaner.

Thank you for the response. I did clean the needle and seat with Gumout, did not make a difference. Would it be possible that the seat material expanded? If I move the float down causing the needle to rise (with effort) I can blow air through the inlet. Too bad there is not an adjustment on the float. I guess the best bet is to just replace the needle and seat again as you suggest.

Very good info here everyone, but i have a twist, same problem on a B&S. I've replaced the carb, engine will only run when primed. I will check for vent troubles, and a cracked primer bulb. In the mean time is there anything else? this mower is ticking me off.

thanks in advance

Zargy

Sometimes the pin that holds the float in place has varnish on it, or rust, too. I would replace the seat and needle. Blow compressed air into the fuel outlet to remove the seat. Use a punch to press in the seat. Put the seat in with the flat side upward.

Zargy, was the carb new? Sounds like one of the jets is blocked. Or it's sucking air in somewhere.

Carb is brand new from B&S. new O-ring between carb and engine. The Primer is attached to the air box portion that mounts to the carb. Fuel line is in good condition, have good flow coming from the tank.

How is the compression in the cylinder? Did you hit something with the blade right before the problem started. If the timing was off, it wouldn't run more than a puff or two.

Does this engine have a carb mounted to the tank? with a bad tank gasket?

Compression is around 60lbs. The carb mounts to the engine, fuel tank is separate gravity type flow. Mower did not hit anything and will rev up nice and then quit like out of fuel, push the primer and it roars back to life but only for a few seconds.

Compression should be checked at wide open throttle. It sounds like your engine should run. There is obviously something wrong inside the carburetor, since you seem to have flow to the carb from the tank. Is there a partially blocked fuel filter in the line. If you loosen the bowl nut, does the gas readily drip out as it should?

Zargy, why not post the engine numbers so we know exactly which carb you have?

Thanks for all the info, fixed my fuel problem ,the brass bowl nut in about ten minutes, runs great now... I was about to trash it when I GOOGLED the problem, and I was directed here and too this forum.
again thanks for the input and ideas

Last year, i had 2 mowers with the same problems, although they had Briggs engines on them.
Upon dismantling the carb from the tank, i found that Briggs had evidently tried to save money, so they had the little spring just setting on top (or under) the diaphragm gasket, in the so-called fuel pump. Nothing else--just sitting there, and it had fallen out of place! For which the owner had set it at the curb on garbage day--and, along came Rusty Jones, and he became "richer" by 2 free mowers!

My craftsman lawnmower 917.387282 starts fine, but continues to rev up and down some. Is this the choke that needs to be adjusted and if yes, how?