Puzzled

[MarineScott]

I have a Craftsman riding mower #917287080 with a B&S 20 hp 31P977 0575E engine. This thing randomly quits as if it is running out of fuel. I have spark, I had replaced the magneto, plug ,cleaned the fuel tank, checked the vent, new fuel lines, filter,clipped the plunger end off the solenoid, ( that worked for at least a year), air filter is good yet it still happens. All parts were replaced under regular maintenance. Now the kicker..... when this stops, if I introduce a little compressed air into the tank through the vent hole, it will start and run. I'm thinking carburetor needs to be replaced.

 

[Hammermechanicman]

Does it have a fuel pump? What fuel filter did you install?

 

[MarineScott]

Does it have a fuel pump? What fuel filter did you install?

No fuel pump, not sure on the brand of filter, it is clear in color (Arnold brand from Tractor Supply)

 

[Scrubcadet10]

Try running it with the gas cap loose, or when it dies, loosen the gas cap and try to start it.

 

[Hammermechanicman]

If it is a gravity fedd system. No pump and tank is higher than the carb. The wrong filter can stop gas flow. Try replacing the filter with a screen type filter as opposed to a paper filter. With the tank near empty remove the fuel line from the carb and see if fuel flows freely.

 

[slomo]

Excellent advice from the above fella's,

Also try removing the blower housing (top engine cover) and cleaning all the dirt, oil, grass and bugs off the engine block cooling fins. Yearly or more if you have oil leaks high on engine. If you neglect this, you will be enjoying your new head gasket repairs, valve seat and or head replacement, engine using oil and so on.

Adjust the valves per YOUR engine spec.

Use a fuel cut off valve and a good paper filter.

Here's another top secret one. Use 100% gas and fuel stabilizer year round. You will never have any carb issues again.

And keep that spark plug changed. That was actually a joke. Think the plug is the first item people change when their mower doesn't run proper.

slomo

 

[slomo]

So to answer your original questions.

Could be the carb needle is sticking closed slightly. Might be some old fuel varnish in the seat area.

Remove the carb. Clean and soak in Diesel. Remove all jets and probe out with a bristle from a nylon brush. Do NOT use torch tip cleaners or any steel wire anything to clean brass jets. Blow out with compressed air. Reinstall and check for proper run. Might take two or three carb cleanings.

Here's another one. Remove all small carb parts. Place carb BODY only, in your WIFE'S dishwasher. That is the best parts washer on the planet. Then come back here and tell us if she catches you LOL.

slomo

 

[Scrubcadet10]

Wix 33011 is the filter i put on small engines, gravity or pump. Remember, the plastic caps on filters go on the carb side of the filter. opposite of the fuel source for proper flow.

 

[gainestruk]

So to answer your original questions.

Could be the carb needle is sticking closed slightly. Might be some old fuel varnish in the seat area.

Remove the carb. Clean and soak in Diesel. Remove all jets and probe out with a bristle from a nylon brush. Do NOT use torch tip cleaners or any steel wire anything to clean brass jets. Blow out with compressed air. Reinstall and check for proper run. Might take two or three carb cleanings.

Here's another one. Remove all small carb parts. Place carb BODY only, in your WIFE'S dishwasher. That is the best parts washer on the planet. Then come back here and tell us if she catches you LOL.

Be sure and do above when wife is NOT home ?
It really does work tho....

 

[MarineScott]

Some very good points, I do try and use non-ethanol fuel. Thanks