Briggs Intek twin 407777-0174-e1

[bertsmobile1]

So going back to basics
pop a can of carb cleaner in your mower and install a pair of in line red spark testers on the plugs
Then go mow
The instant it stops look at the spark testers .
If they are flashing red but the engine is cranking but not running then the ignition system is fine & the fuel system is suspect
Give the carb a shot of carb cleaner & crank the engine if it fires right up and you can keep it running for a minute or so by repeated short shots of carb cleaner then that confirms a fuel problem.

If it does not fire or won't stay running then you have a valve problem, most likely a badly worn cam lobe.

I have a one gallon tank of a Tecumseh walk behind that I use as a substitute fuel supply ( cause it has an inbuilt tap ) that I slip directly onto the carb.
Problem persists then the problem is in the carb.
Problem goes away then the problem is in the fuel supply

Not going to fix the problem but at least you will then know where to spend time looking.

If the carb is not a problem then I move the external tank connection further back.
If I get to the last element and the problem is still there then I know the tank is the culprit.

Beauty of working this way is you are doing your diagnosis while you are mowing so the grass is not reaching sky ward while you are beating your head against the wall .
Also you don't end up spending a fortune on replacing perfectly good parts.
Most people have an old push mower, tiller or something with a 1/4" fuel take off kicking around their sheds.
If not every mower repair shop ( not glass front sales rooms ) will have boxes full of old tanks that we all keep but never seem to use.

 

[Curleyg]

Bertsmobile1, thanks for all these tips. I'll try them all. Since this model has a fuel pump, any reason I can't just hook a fuel line to the pump (which has been replaced) and drop the other end in a gas can sitting on the deck in front of the seat? Btw I'm on the east coast so it's raining all week so it will be awhille before I can get back to it.

 

[bertsmobile1]

You can do that .
However that will only tell you if there is a problem between the fuel tank & the fuel pump.
The basic idea is to substitute with a known good fuel supply and test each part , one at a time.
It is a process of elimination

 

[Curleyg]

Got it. Thanks

 

[Curleyg]

Got it. Thanks

Ilengine, I'm not going to say it's fixed but, I decided to check the hot carb theory first since it seemed easy. I started looking to see what I had to remove so I could check the carb when it failed. The first thing I saw was the heat shield you mentioned, and it does direct all that hot air directly on the carb fuel bowl. It also blocks any potentially beneficial cool air from getting to the engine. I really couldn't see any need for it so I removed it. Two bolts. Then I mowed for an hour and a half and it was still purring when I put it up. I found it funny that the heat shield was even tilted toward the engine to make sure all that hot air hit the carb. I've got it all cut now so it'll be awhile before I'll be convinced that fixed it.
Thanks to all for the suggestions and tips. Bertmobile1 I'll keep the troubleshooting tips in mind next time one of them fails.
Happy mowing.

 

[ILENGINE]

I had a customers rider that drove me nuts one summer due to that issue. And this was a Craftsman under warranty that the sears tech couldn't figure out.

 

[Curleyg]

I had a customers rider that drove me nuts one summer due to that issue. And this was a Craftsman under warranty that the sears tech couldn't figure out.

Final post. Removing the heat shield fixed it. I mowed for two hours yesterday, didn't spit or sputter once. I'm thinking of making a short youtube video. Maybe help someone else. Thanks to all for the tips.