Electrical thingy on bottom of genset carb

junkhound

junkhound

Senior Member
Location
Renton, WA
Occupation
EE, power electronics specialty
Kinda tongue in cheek post, but wondering what all the different reasons folks have heard about what these are and what for.

Own take is 100% due to EPA, no good tech reason, and zero impact to genset electrical function.

In addition to GW/CC have seen 'explanations' of oil dilution, backfire , house fires, NEC compliance, engine longevity, fuel leaks, and plug fouling.

PS: dual fuel carbs may be a valid useful function ?
 
Last edited:
All it’s for is shutting off the gas flow to the carb while the engine isn’t running. Lots of small engines have it, including lawnmowers. Prevents engine from hydrolocking due to leaky carburetor float. In the old days, I would cut in a shutoff valve in the gas line.
 
hillbilly1 said:
All it’s for is shutting off the gas flow to the carb while the engine isn’t running. Lots of small engines have it, including lawnmowers. Prevents engine from hydrolocking due to leaky carburetor float. In the old days, I would cut in a shutoff valve in the gas line.
Click to expand...
What is this "Thingy"? I have several engines I use, and I still use the gas shut off valve and allow the engine to die. Not all the engines have a shut-off valve, including my lawn tractor. I have considered installing one.
But I have always wondered about gas remaining in the bowl.
I have not seen this "thingy" or have not paid attention to it. TIA.
 
junkhound said:
Kinda tongue in cheek post, but wondering what all the different reasons folks have heard about what these are and what for.

Own take is 100% due to EPA, no good tech reason, and zero impact to genset electrical function.

In addition to GW/CC have seen 'explanations' of oil dilution, backfire , house fires, NEC compliance, engine longevity, fuel leaks, and plug fouling.

PS: dual fuel carbs may be a valid useful function ?
Click to expand...
Are we talking gasoline burning unit or LP/NG burning unit?

Gasoline be more common with portable units than fixed units.

Diesels don't have a carb, but usually have a fuel solenoid and one of it's primary functions is to stop the engine by cutting off fuel.

Another thought if this is a gasoline engine is maybe they gone away with the old venturi method of introducing fuel and this has an electronic fuel injector but still has similar look of the old carburetors to anyone not paying much attention? Easier to just modify that part then redo even more things to inject fuel someplace else?
 
Years ago (I'm so old...) Briggs & S sold a small, in line, gasoline, shut off valve. You'd splice it in before the carb, as others already mentioned.
Best part, the plastic on / off valve turned SO easily! AND... was cheap. I bought 5 of them, wish I had purchased 20.
Bill
 
what is the thingy? i have some inverter generators that have a little stepper motor on the bottom of the carb that moves the throttle.
 
junkhound said:
Kinda tongue in cheek post, but wondering what all the different reasons folks have heard about what these are and what for.

Own take is 100% due to EPA, no good tech reason, and zero impact to genset electrical function.

In addition to GW/CC have seen 'explanations' of oil dilution, backfire , house fires, NEC compliance, engine longevity, fuel leaks, and plug fouling.

PS: dual fuel carbs may be a valid useful function ?
Click to expand...
Yep. One I saw (and "fixed") had a solenoid that had to be energized to run on gasoline. De-energized it could run on propane. The switch was left in the "Gas" position and ran the little battery down.
 
Being that is at the bottom of the bowl, perhaps a "WIF" ("Water In Fuel) sensor?
It could also be a solenoid, that opens & closes, stopping fuel at/into the main jet.
 
Removed the one on my genset today, soldered a copper sheet over the hole, runs fine.
It was a spring loaded solenoid pintle valve that blocked fuel flow when gen set off.
Apparenly EPA mandated to prevent fuel vapor on the few engine revs after the spark is turned off.
 
retirede said:
I had a mower with one of those (Kawasaki engine). It’s a valve that prevents gas in the bowl from flowing into the carb when it’s de-energized. It prevents run-on (dieseling) on shutoff.
Click to expand...
I have a twin cylinder B&S with set up like this.
 
You must log in or register to reply here.
Top