Old crafstman mower wont run unless primer is pushed every 3 seconds

[Nathan]

I have an old craftman mower. It starts right up after 5 quick primes, but then the only way to keep the mower running is to push the primer button every three seconds. If you dont push it, it just runs for about 5 seconds and then dies. Why?

[Joseph Meehan]

I would look for an air leak in the fuel supply.

[Steve B.]

Probably the carb is clogged with crud or the fuel pump (cheap little diaphragm) has failed. You can clean it up and get it going again if you are at all mechanically minded.

Steve B.

[zxcvbob]

Take the drain plug out of the bottom of the carburator bowl and let an ounce of dirty gas drain out. While the drain plug is out, clean the crud out if the hollow in the drain plug. There's supposed to be some kind of jet in there. When it's partially plugged up, or there's just a little water in the carburator bowl, it will act just like that.

Also check for a small crack in the priming bulb.

Best regards, Bob

[Chip Stein]

clean the carb. it's a fuel problem Chip

[jim]

two things i think of: 1-remove gas cap and then start it up.. if it keeps running then you need to clean the gas cap.. the vent hole is plugged. 2- the carb. is dirty and not letting gas into the engine... when you prime it you bypass the little opening where the gas comes out to the engine... after the gas in the primed area is burned up it will kill... kinda like telling you someting- the carb. is dirty.....

[Bob S.]

OK experts, a related problem: same type mower and almost same type problem.

Ditto all the OP's comments, except after about the third time of repriming it will run ok. It doesn't matter if you push the primer bulb 5 times, 8 times, or 10 times - it will run for a few seconds then quit. After the 3d time of doing this it will start & run ok. This would make me think the problem is not a dirty screen, bad fuel pump, or clogged jet. What else??

Bob S.

[Steve B.]

It's one of these things. I would go with the fuel pump or just plain dirty in the carb. By the third time around you have pulled enough gas through the system to get it going.

Steve B.

[HRL]

Your mower has a fuel pump?

[Steve B.]

Many of them do have one of sorts. It is really just a plastic/rubber diaphragm usually between the carb and gas tank. Others use gravity feed to the carb.

Steve B.