One for you (lawnmower) engine guys?

[calebp]

Hey Guys,



Need some help from the (lawnmower) engine gurus. Sorry in advance for the for the wall of text. I have a Toro LX426 lawntractor. Yesterday I went to fill up the gas tank and the nozzle on the gas can popped off into the tank. I fished out the nozzle and spring (the twisty, press the nozzle down style gas can) from the gas tank using a coat hanger and finished filling the tank. Put the gas cap back on and tried to start it but it would not. Drained the gas tank, removed the fuel line from both sides of the fuel filter and sprayed the fuel filter out with water. Then blew fuel filter dry and for good measure ran some gas through it just to make sure all the water was gone. Reattached fuel lines to each side of the filter and gas appeared to be flowing freely through line and filter. It started right up and ran for about 30 seconds, then same old story. Stopped as if it was out of gas and would not start back up. Drained gas tank, removed the fuel filter from both sides of the tube and attempted to start it with no lines/filter attached. It fired right up and ran for about 4 seconds burning of the gas already in the engine I guess? What could be causing this? Does the fuel filter regulate fuel flow into the engine or just make sure its clean along the way? Going to look for another fuel filter today but not sure if that’s kind of a general part or I will need something specific that I can’t grab at my local ACE. Why would it start without fuel line attached but not when fuel is attached and for all appearances flowing freely?



Thanks!

 

[savannahboy]

Be sure your mower cap is venting. If that hole is blocked, it will start and run only briefly.....Bill

 

[GeauxLSU]

If you've confirmed fuel is freely flowing it's not a fuel problem. Clean plugs and air filter?

 

[MegaFan]

Yep, they covered it. Only three things needed... fuel, air, and spark (or heat of compression for diesels). If you've done the basics (confirmed fuel flow and checked for spark), I would also suspect an air issue, which is often a dirty air filter. For fuel to flow, the tank must vent, as stated, so try cranking and running with the cap loosened or off just to confirm you're not pulling a vacuum on the tank, starving the fuel.

 

[BHJ]

Yep wrong or broken gas cap will cause what you describe. Vapor lock.

 

[Hayata]

Have you used ethanol-free gas for the engine?

If not, you could have some seals in the carb going south.

I'm a big fan of Sea Foam for keeping the fuel system from gunking up. Once you get her runnin' again.

Good luck!

[Broken External Image]:

 

[dial1911]

Try cranking it with the gas cap off or loose and see if it runs for longer- sounds like it's being starved for gas. The bowl on the carb is probably filling up while it's not running and that's all the gas it has to burn, until the bowl fills back up again.

Any chance the coat hanger fishing broke something loose- even paint/gunk from the walls of the fuel tank. That could have partially plugged up something in the tank/line before the fuel filter.

 

[calebp]

Well, hooked the fuel lines back up to original filter, put gas back in the tank and it started and ran for 15 seconds then started idling oddly, running well then bogging down sort of screwed gas cap back on, ran good. Absolutely zero clue what the problem was but it's running good again. Thanks for the advice guys!

 

[dial1911]

Sweet! Love an easy fix- whether it's intentional or not.

 

[jimmythegem]

Have you used ethanol-free gas for the engine?

If not, you could have some seals in the carb going south.

I'm a big fan of Sea Foam for keeping the fuel system from gunking up. Once you get her runnin' again.

Good luck!

[Broken External Image]:

I had to replace carb on my mower yesterday because of gunk caked around bowl and left space around O ring that allowed small particles of gunk into carb.
After replacing carb, cleaning out gas tank, replacing plug, it still wouldn't start.
Air filter looked clean but took it off and engine started and ran fine. Put air filter back on and wouldn't start.
New air filter cured my problem.
Ethanol free gas or sea foam will be used on my mower from now on.