Fuel problem -- at least I think

z1haze

Forum Newbie
Joined
Jul 1, 2018
Threads
2
Messages
5
Hi, I have an older Simplicty rider with a 12.5HP Briggs V twin engine. It has always ran excellent (probably 20 years) until this spring. We had to leave it outside last winter (covered) due to issues where there was a place to keep it.

Anyway, this spring it wouldn't start. I replaced the air filters, fuel filter, spark plugs, fuel pump, ground the bottom half of the fuel shut off solenoid off, ran a compression test (100 psi), took the carb off and cleaned it, no blockages anywhere -- I just can't get the damn thing to run. The bowl fills with fuel, but it will not exit the bowl. It will run on carb cleaner, but there is absolutely no gas coming from the bowl into the throttle plate area. I took the carb apart multiple times to check/clean and i can spray carb cleaner right through the jet and up into the throttle body. The bowl is definitely getting fuel, if I loosen the drain screw fuel will drain from the bowl. My understanding is that this fuel pump works off the engines pressure/vacuum, pushes the fuel into the bowl, when the bowl fills up the float closes the value and i guess pressure is what forces the fuel up into the top top of the carb?

Carburetors are a bit before my time, so I never had an education on them, maybe I am missing some important piece here. please help!
 

cpurvis

Lawn Addict
Joined
Aug 25, 2015
Threads
21
Messages
2,256
ground the bottom half of the fuel shut off solenoid off,

Could this be the reason? Why did you do this?
 
Joined
Jul 22, 2017
Threads
21
Messages
2,154
Wow you got a good 20 years out of that one........ When you say you cleaned the carb, What procedure did you use ???????

It takes me about 30 minutes to clean a carb well.......... That's after soaking it in carb acid for a while.....

What is Your Model # on the Engine ?????
 

z1haze

Forum Newbie
Joined
Jul 1, 2018
Threads
2
Messages
5
I'll get back out to the mower this afternoon for the model number, but I can describe cleaning it.

I removed it from the mower, removed the bowl, removed the jet, and used carb cleaner and sprayed through all of the openings ensuring that there was a free flow of carb cleaner through everything. Other than that I dont know much about carburetors. I worked as a mechanic briefly maybe 10 years ago or so, so I dont have a whole lot of experience.

I did however finally get it running, I had to adjust the screws, backing them out quite a bit. I guess there must be an air blockage in there somewhere that I've missed still, if I have to back the screws out as far as I did to get it running well.
 

z1haze

Forum Newbie
Joined
Jul 1, 2018
Threads
2
Messages
5
Could this be the reason? Why did you do this?

No, I don't believe so -- this is a pretty common thing to do if they go bad and don't want to replace them. The only purpose of it is to close fuel from when the key is turned off
 

cpurvis

Lawn Addict
Joined
Aug 25, 2015
Threads
21
Messages
2,256
No, I don't believe so -- this is a pretty common thing to do if they go bad and don't want to replace them. The only purpose of it is to close fuel from when the key is turned off

I think the way it works is that it opens with the key on, meaning it's normally closed unless power is applied.
 

z1haze

Forum Newbie
Joined
Jul 1, 2018
Threads
2
Messages
5
I think the way it works is that it opens with the key on, meaning it's normally closed unless power is applied.

that's literally what I just said.
 

cpurvis

Lawn Addict
Joined
Aug 25, 2015
Threads
21
Messages
2,256
that's literally what I just said.
No, it's a little different. If, like I surmised, it takes power to hold the solenoid open so that the engine can run, how are you accomplishing this now?

What took the place of the solenoid and is allowing fuel to flow to the engine?
 
Top