Fuel shut off solenoid

[Gcorron]

Curious here, I have an SV-590 on an Ariens mower. It has done well for 6 years, but the other day it started, ran for a minute, then started sputtering. I shoved the throttle up in choke, and it sputtered on, but would die when I would return it to the run position.

The thing has been 'backfiring' when you turn it off, almost every time regardless of throttle position. I am leaning towards the fuel shut off solenoid as the culprit here, and hope to get it checked out this afternoon, I've already removed the shroud.

What happens if I simply replace the solenoid with a plug in the carburetor bowl? It's not like a diesel where the shut off solenoid stops the engine, these stop by throwing ground in the magneto circuit, so what is the harm? Looking at Kohler parts, it does not appear like they list a solenoid separately.

I have some running around to do this afternoon, and hope to get back to it. BTW, it will not fire at all now.

Just curious,

George

 

[Lawnranger]

Although it's not recommended, you can remove the solenoid, cut off the end of the plunger and reinstall the solenoid (same effect as installing a plug). You may have other problems and will have to diagnose those on a case by case basis.

To help prevent backfire during shut down, try idling the engine for 30 seconds before shutting off the ignition. This procedure allows the muffler to cool down a bit so the fuel does not ignite during shut down.

 

[7394]

Testing the carb solenoid is easy, just turn on the key & listen near carb for a click that would be the solenoid opening the plug to main jet.

Then turning key off should have an audible click as well. But you would resally need to be close & listen hard. The purpose of this shut off is to stop gas from gravity feeding gas into a shut off engine & filling the crankcase with gas.

It's a good idea, I wouldn't remove it, it it were mine. But I would add a gas shut off valve near carb.

 

[bertsmobile1]

Testing the carb solenoid is easy, just turn on the key & listen near carb for a click that would be the solenoid opening the plug to main jet.

Then turning key off should have an audible click as well. But you would resally need to be close & listen hard. The purpose of this shut off is to stop gas from gravity feeding gas into a shut off engine & filling the crankcase with gas.

It's a good idea, I wouldn't remove it, it it were mine. But I would add a gas shut off valve near carb.

Got nothing to do with the mower and everything to do with the shinny bums in town hall.
Fuel shut off are there to prevent you causing catastrophic atmospheric pollution by having the engine revolve 5 or 6 times with no spark thus blowing unburned fuel strait out of the exhaust.
It was the best compromise that the mower companies could come up with.
What the shinny bums really wanted was catalytic converters ( after burner by any other name ) to be a mandatory fitment .
Shoving a plg up the main jet orrifice will not stop a malfunctioning float valve from filling the crank with fuel unless the carb is fitted with an external overflow.

 

[Lawnranger]

Testing the carb solenoid is easy, just turn on the key & listen near carb for a click that would be the solenoid opening the plug to main jet.

Then turning key off should have an audible click as well. But you would resally need to be close & listen hard. The purpose of this shut off is to stop gas from gravity feeding gas into a shut off engine & filling the crankcase with gas.

It's a good idea, I wouldn't remove it, it it were mine. But I would add a gas shut off valve near carb.

Got nothing to do with the mower and everything to do with the shinny bums in town hall.
Fuel shut off are there to prevent you causing catastrophic atmospheric pollution by having the engine revolve 5 or 6 times with no spark thus blowing unburned fuel strait out of the exhaust.
It was the best compromise that the mower companies could come up with.
What the shinny bums really wanted was catalytic converters ( after burner by any other name ) to be a mandatory fitment .
Shoving a plg up the main jet orrifice will not stop a malfunctioning float valve from filling the crank with fuel unless the carb is fitted with an external overflow.

Actually, that is an anti-afterfire solenoid to prevent the loud bang when shutting down a hot engine (see my previous post for shut down instructions).

The needle & seat, if working properly, will prevent fuel from getting into the crankcase while the engine is off. Adding a manual shut off in the fuel line is a good preventative but it's just a cheap band aid if the needle & seat are leaking. Fixing the root problem is always best.

 

[bertsmobile1]

Actually, that is an anti-afterfire solenoid to prevent the loud bang when shutting down a hot engine (see my previous post for shut down instructions).

The needle & seat, if working properly, will prevent fuel from getting into the crankcase while the engine is off. Adding a manual shut off in the fuel line is a good preventative but it's just a cheap band aid if the needle & seat are leaking. Fixing the root problem is always best.

If the needle & seat are working properly you do not need a very expensive solenoid in the carb to prevent the crankcasr from filling with fuel either.
Don't believe me. I am just some electrons wizzing around in cyberspace.
However when you take the mower in for service ask them to remove the solenoid and see what response you get.
The bang in the exhaust is a byproduct of it being there, not the reason.
EPA legislation is the reason.
And more EPA lean burn legislation is the reason why the muffler is so hot that the unburned fuel ignites in the first place.

 

[Gcorron]

Thanks for the replies guys, I really appreciate the time. I'm working on this thing as time permits, and quitting when aggravation sets in!! THAT is the luxury of owning a little Kubota BX-25 with a 60" belly mower, I really don't much CARE when the old riding mower gives out on me!

I took the solenoid out, and the first suspicious thing was that it was dry as a bone, and no fuel leaked from the bowl. The solenoid worked on the bench, but would not return to normal when voltage was removed. a little WD-40 (amazing stuff, ain't it?) loosened it up, but who knows for how long.

I took the opportunity to go get a new fuel filter and fuel line, since it was all looking pretty old, and replaced it all tonight, but still no joy. It looks like the fuel pump may not be working. I'll let you know, likely be able to check it tomorrow sometime.

I didn't tell the other problem at the beginning. The day it quit working, I just shoved it aside and the next morning the battery was DEAD, DEAD, DEAD! Not a volt measured. Put the charger on it for overnight and it did not take a charge, something broke in side the battery. So let's see, battery, fuel pump, and the tires keep going flat, so it's either tubes, or new tires, this thing is beginning to push it's luck!!

Thanks guys, I'll keep in touch!

George

 

[Lawnranger]

If the needle & seat are working properly you do not need a very expensive solenoid in the carb to prevent the crankcasr from filling with fuel either.
Don't believe me. I am just some electrons wizzing around in cyberspace.
However when you take the mower in for service ask them to remove the solenoid and see what response you get.
The bang in the exhaust is a byproduct of it being there, not the reason.
EPA legislation is the reason.
And more EPA lean burn legislation is the reason why the muffler is so hot that the unburned fuel ignites in the first place.

Check this out straight from the horse's mouth and educate yourself a little further: Why Does My Engine Backfire or Afterfire? | Briggs & Stratton FAQ and please don't try to convince me you know more than the engineers.

If you think an anti-afterfire solenoid, and that's what it's called, is there to prevent gas from entering the crankcase then please explain why there are millions of small engines produced, and still being produced, that have a gravity fed carburetor and no anti-afterfire solenoid.

The real reason the anti-afterfire solenoid is installed on some engines is because the end user complained so much about the afterfire (bang after shut down).

 

[Lawnranger]

Thanks for the replies guys, I really appreciate the time. I'm working on this thing as time permits, and quitting when aggravation sets in!! THAT is the luxury of owning a little Kubota BX-25 with a 60" belly mower, I really don't much CARE when the old riding mower gives out on me!

I took the solenoid out, and the first suspicious thing was that it was dry as a bone, and no fuel leaked from the bowl. The solenoid worked on the bench, but would not return to normal when voltage was removed. a little WD-40 (amazing stuff, ain't it?) loosened it up, but who knows for how long.

I took the opportunity to go get a new fuel filter and fuel line, since it was all looking pretty old, and replaced it all tonight, but still no joy. It looks like the fuel pump may not be working. I'll let you know, likely be able to check it tomorrow sometime.

I didn't tell the other problem at the beginning. The day it quit working, I just shoved it aside and the next morning the battery was DEAD, DEAD, DEAD! Not a volt measured. Put the charger on it for overnight and it did not take a charge, something broke in side the battery. So let's see, battery, fuel pump, and the tires keep going flat, so it's either tubes, or new tires, this thing is beginning to push it's luck!!

Thanks guys, I'll keep in touch!

George

Make sure the fuel line from the tank to the pump is clear and also make sure the impulse line to the pump is not leaking. The impulse line is the short line that usually goes to a valve cover or crankcase to carry the vacuum/pressure pulse to operate the fuel pump. Many fuel pumps have been replaced only to find out the impulse line was cracked.

Good luck and let us know what fixes the problem.

 

[bertsmobile1]

How the carb is fed makes no difference. If the fuel level is higher than the float needle valve face the fuel can syphon.
FWIW most AYP mowers are buit to California legal specs and have solenoids fitted.
They are not a legal requirement down here but I see identical tractors in my shop, a USA grey import will nearly always have a solenoid.
The Australia import version, if there is one ( AYP excluded ) does not have a solenoid.

And perish the thought some times the marketing departments tell porkies to make imposed changes palatable to purchasers.
It also discourages the anti town hall red necks from ripping them off & chucking them away.
Even governments will find some positive spin to put on an onerious imposition.

If you don't want the mower to after fire all you need to do is to throttle down for a few seconds.
If the mower companies wanted to stop it all they had to do was add about 3" of exhaust pipe which is a lot lot lot lot cheaper than shoving a $ 50.00 airtight anti spark fuel explosion safe solenoid on the end of the float bowl.
However they could not do that because the muffler has to run hot enough to burn the fuel that the engine does not which was again the cheaper alternative to fitting a real afterburner which is called a catalytic converter another bald faced lie to make the $ 1000 box on your cars exhaust pallatable to Joe public.

Now if you really want to get it from the horses mouth, ring your local EPA and ask them if you are allowed to remove it.
So I have been told fines in the thousands for tampering with them in some states.
No idea about local regulations in Texas but I but a lot of engines from the USA shipped from Long Beach Ca and it is always a real PIA to get non -Cal compliant engines shipped to my consolodating agent in California prior to shipping.