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Tonight I went to start my Craftsman lawn tractor to mow the lawn - it cranked and cranked but didn't act like it wanted to start at all. I went and grabbed a can of starting fluid and sprayed a little in the carburetor. The engine fired for a second or two, just long enough to use up the starting fluid. I pulled the fuel line loose from the carburetor and gas flowed out just like it should. I noticed that in the bottom of the carburetor there is an electric fuel solenoid - could it perhaps have burned out? It's like gas gets to the carburetor but is not getting fed to the engine. I just mowed about a week and a half ago and it ran great. My engine is a 17.5 HP Briggs and Stratton engine model #31C707.

Yes,
Check you get 12 V to it when the ignition is turned on.
Take it off by turning it by the flats you might need to grind down an open ender to get in there.
Because it is at the bottom of the bowl all the junk & water end up there and gum it up.

bertsmobile1 said:

Yes,
Check you get 12 V to it when the ignition is turned on.
Take it off by turning it by the flats you might need to grind down an open ender to get in there.
Because it is at the bottom of the bowl all the junk & water end up there and gum it up.

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I think I have the same engine as OP and maybe the same problem. What is the purpose of the solenoid?. I have had older craftman r. mowers and they didn't have sol. on the carb. Also, when you turn the ign. sw. on, should you hear the sol. click?

tolona said:

I think I have the same engine as OP and maybe the same problem. What is the purpose of the solenoid?. I have had older craftman r. mowers and they didn't have sol. on the carb. Also, when you turn the ign. sw. on, should you hear the sol. click?

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If you ask one of those "Pencil D**ks" that featured in the original Ghost Busters, it is there to maintain life on the planet. :confused3:
When you shut down the engine, it revolves 3 to 10 times before it stops.
this means 4 to 10 drops of fuel are draw into the carb and because there is no spark to ignite them, pass unburned into the atmosphere, shock horror, well all be killed. :shocked:
The solenoid jambs a ram up the coit of the main jet to stop this happening.
On some very lean burning engines and others that have an after burner built into the muffler ( thanks to the said same Pencil Di*ks ) the accumulated unburned fuel will go bang in the muffler, anything up to a minute after it is turned off.

Tampering with it has massive fines in some counties .


Now to be totally fair, it does have a safety purpose, being that if the cut out wire on the magneto happens to fall off or get cut, no fuel will also shut down the engine

So if the solenoid wasn't working, the engine should still run? Or if it wouldn't run without the solonid working could you take the solenoid off, remove the plunger, then put it back on the carb. , could it run then?

No it is spring loaded closed.
When 10V or more is applied the solenoid pulls back against the spring to open it.
Because it is in the absolute bottom of the float bowl all of the crud that ends up in the carb, ends up around this plunger which corrodes or just gets stuck so preventing the solenoid fully opening.
Down here, up until 2020 I can cut them off.
After that there will also be massive fines for doing it down here too.
One jumbo dumps hundreds of kilograms of unburned fuel every time it takes off, but that is OK but your tin small lawn mower is a national ecological disaster :confused2:

Here in US it would fall under the purview of the "Environmental Protection Agency" A giant beaurocracy set up yrs' ago to harass citizens and cost them money and time.... When I take the plunger out my carb. solenoid, i'll do it under the cover of darkness so the EPA won't catch me out for destroying the planet. HAH. It was Democrats...

Another thing the EPA has managed to do which has cost consumers billions is mandate catalytic converters on cars. These things can get plugged and they can cost like 15-18 hundred dollars which might be more than your car is worth, so you would junk it. My 1995 Oldsmobile 88(it's got every option) was starting to do this, so I just dropped the exhaust pipe rear of the Cat. con. then using an extension drill bit, I went in there and reamed out the c. c. Not hard to do at all, but you can't get a mechanic to do this because they.re afraid of the EPA. Not only did I save my beloved Olds from the junkyard, She runs better than ever!! You wouldn't believe the number of Buick Rivieras that have gone to the junkyard because of the Cat. conv.

Down here, removing or bypassing the cat carries a $ 15000 fine for the first offense and it doubles for each & every subsequent offense.
Too many and you become a serial offender , loose your ticket & can get a 12 year stretch.

The reason for it is to allow ou to burn all the rubbish that is left over from the oil after the refinaries have made all the plastic, lubrication oils, fertilizers & other petro chemicals.
Tip a dish of fuel out and leave it in the sun
After a day or so you will find the dish 1/4 full of a dark, foul smelling sticky goo.
This what will not burn in your engine and gets burned by the cat.
If your car was a jet engine the device would be called an afterburner.
But if the auto industry called it that some people might (Rightfully so ) why they are paying for fuel that their engine can not burn.
It is another case of big business buying the ears of the governments and making the public pay for cleaning up fuel which should have been done at the refinery.

But then a gallon of gas would cost more money and we would all scream it cost too much.:laughing::laughing::laughing:
Sheep.
Ignorance is bliss.

Yes that is exactly what would happen.
This would be followed by pressure for more fuel efficient engines and a trend towards smaller cars.
And we couldn't have that happen could we.

I had worked on a John Deere 170 at one time that had a bad fuel solenoid, and just to check it we cut plunger off. It still runs today with that same solenoid in it.

Sad thing is it runs better with the solenoid cut off, than it did when it was fully functional.