Fuel Flow Problem?

[The_Nuke]

I pulled the lawnmower out of storage today, put some gas in it, and it started on the first pull. I proceeded to begin mowing the yard, and everything was fine for about 10 minutes. Then the engine sputtered and died as if it were out of gas. It was not. I tried pull-starting it again, and it would sputter a little but never stay running. One of the times I reached down and began pumping the primer bulb, and that kept it running as long I continued to pump the priming bulb. As soon as I stopped pumping the bulb, the engine would sputter and die a few seconds later.

There appears to be some sort of issue with the fuel delivery, but I am a novice when it comes to these small engines. Any advice on how to proceed is appreciated.

Pertinent details:
- mower is a Craftsman 20" side-exit push model with mulching capability.
- engine is 4HP Husqvarna (sp?) and is 2 years old max (unknown exact born on date; was purchased used last year).
- engine oil is fresh (changed last season before putting up for winter).
- gasoline was fresh; 93 octane purchased this morning.

 

[LazyDog]

Your carburetor needs some TLC or cleaning.

 

[Matagonka]

Did you leave it with gas in it over the winter? Probably a clogged carb.

 

[Eddie]

Check to make sure the gas cap vent is open. Ed

 

[Lyman]

Does your carburetor have the main jet screwed into the bottom of the float bowl? It needs to be cleaned. You also need to treat your fuel.

 

[bubbatime]

Most Chinese carbs are $8-$20 on ebay/Amazon. Throw a new carburetor on it. Its only a few bolts. Don't waste your time attempting to rebuild a carb that cost under $20.

 

[The_Nuke]

Originally Posted by Matagonka
Did you leave it with gas in it over the winter? Probably a clogged carb.

I drained the gas out of the fuel tank before putting it up for winter.

 

[The_Nuke]

Originally Posted by Blkstanger
Does your carburetor have the main jet screwed into the bottom of the float bowl? It needs to be cleaned. You also need to treat your fuel.


I do not know what the jet configuration is, I will have to look at it more closely and see what the setup is.

I treat the fuel with some MMO or B12 Chemtool if I don't have any MMO on hand.

 

[The_Nuke]

Originally Posted by bubbatime
Most Chinese carbs are $8-$20 on ebay/Amazon. Throw a new carburetor on it. Its only a few bolts. Don't waste your time attempting to rebuild a carb that cost under $20.


I will check into that, thanks!

 

[Surestick]

Originally Posted by Eddie
Check to make sure the gas cap vent is open. Ed


This as a first step. It's easy to test. When it dies, unscrew the gas cap, screw it back on and try and start the mower. If the same thing happens (15 min run time then it dies) then your gas cap isn't venting if it still won't start then it's probably your carb.

 

[The_Nuke]

Originally Posted by Surestick
Originally Posted by Eddie
Check to make sure the gas cap vent is open. Ed


This as a first step. It's easy to test. When it dies, unscrew the gas cap, screw it back on and try and start the mower. If the same thing happens (15 min run time then it dies) then your gas cap isn't venting if it still won't start then it's probably your carb.


I've tried it with gas cap off and on, but it won't start up and stay running unless I continually prime it with the primer bulb

 

[slomo]

Originally Posted by The_Nuke
Originally Posted by Surestick
Originally Posted by Eddie
Check to make sure the gas cap vent is open. Ed


This as a first step. It's easy to test. When it dies, unscrew the gas cap, screw it back on and try and start the mower. If the same thing happens (15 min run time then it dies) then your gas cap isn't venting if it still won't start then it's probably your carb.


I've tried it with gas cap off and on, but it won't start up and stay running unless I continually prime it with the primer bulb


Your carb is dirty/clogged up. It will run with extra fuel from the primer bulb, meaning it's starving for fuel. MMO and B-12 are not fuel stabilizers so those won't work for you. Also draining the tank only does not empty the carb. If you have a steel gas tank, in the fall, drain the tank and let the engine die from lack of fuel. This will remove the fuel in the mower. So no chance of fueling issues come spring. Then spray fogging oil into the steel tank to prevent rusting of the tank. OR use stabilizer all the time and never worry about dirty carbs again. And never use ethanol fuel of any kind in outdoor power equipment. 100% real gas is your friend.

 

[mk378]

In a very few cases this can be cleared by taking the air cleaner off, get it running, then completely block the intake with your hand for a second. That creates a powerful vacuum that might pull the crud through the carburetor jet. Otherwise you'll have to take the carb off and clean it, which really isn't a big deal.