# Carburator electric wiring



## bripatch1 (Jun 13, 2011)

I am swapping engines, from 12.5 hp powerbuilt OHV Briggs and Stratton (which is
toast) to a 14.5Briggs and Stratton I/C Quiet OHV model 287707, on a 40 inch 
Murray riding mower. Question... Can someone tell me what the two wire
connection to the carburetor (Walbro 694918) which attaches to the carb float
cover is for? Also, since my machine never had one to begin with, what effect
will it have if it's not hooked up ? Regards, from Bripatch.


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## jhngardner367 (Apr 5, 2011)

Those wires are for the fuel shut-off solenoid.It shuts off fuel flow to the main jet,when the key is turned off.One wire will go to the wire that is hot,both on cranking,and running positions.Check it with a voltmeter,to find out which wire it is.The other wire,is a ground wire. You want power to the hot side,during crank over,and running,but not on the off position .If it's not hooked up,the carb won't get fuel.


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## Country Boy (Mar 18, 2010)

jhngardner367 said:


> Those wires are for the fuel shut-off solenoid.It shuts off fuel flow to the main jet,when the key is turned off.One wire will go to the wire that is hot,both on cranking,and running positions.Check it with a voltmeter,to find out which wire it is.The other wire,is a ground wire. You want power to the hot side,during crank over,and running,but not on the off position .If it's not hooked up,the carb won't get fuel.



What he said. :fineprint

I did a similar swap for a customer on a Scag mower, and I ended up having to install a new key switch that had a terminal that was hot during cranking and normal running. Just ran a wire from there to one of the wires on the fuel solenoid, and the other wire went to ground. Doesn't matter which one is power and which one is ground on the solenoid.


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## bripatch1 (Jun 13, 2011)

Thanks jhngardner 367 I was able to run power and ground wires to the fuel shut off solenoid as instructed and functionally tested the connections with a test light in each mode (crank, run and off). Engine will start on starter fluid but after a few seconds dies out. Gas tank is full, the inline fuel shutoff valve is open and fuel is available into the carb fitting. The float bowl however still appears to be empty. 
I need to know a little more about that solenoid shutoff valve : maybe how it can be removed (and tested) and allow access to the carb float itself (and its float valve). Even better can it be set to remain open as its default power off
state? Maybe that's wishful thinking on my part. Regards from Bripatch.


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## dangeroustoys56 (Jul 26, 2010)

its an antifire solenoid - some sort of saftey device for keeping gas from overflowing into the combustion chamber - in my opinion theyre a hassle. Sometimes they stick ( probably from the cruddy gasoline today) and cause issues.

I have a 2003 murray with a 16.5HP single that has the solenoid, would stutter and sputter and diesel when shutoff - i snipped the tip of the solenoid off ( inside the carb) , put it back in the carb and it ran beautiful afterwards.

To combat the fuel leaking into the combustion chamber, i shut the manual fuel valve off, let it idle till the carb empties of fuel and it dies (less then 5 minutes) then put it in the shed.

You can try to free up the old solenoid or buy a new one - but a waste of money i think.


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## jhngardner367 (Apr 5, 2011)

Take the solenoid out,connect it to power,and see if it's actually moving,or if there's dirt/corrosion on it.When you put pwer to it,you should feel,and see it move,slightly.Push down on the plunger,to see if it's free.If it moves with your finger,but not with power,it's bad,and you can do 2 things:Replace it($50),or, as DT56 suggests,nip off the end,and use the manual shut off valve.


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## bripatch1 (Jun 13, 2011)

Thanks, I cycled power through the fuel shutoff solenoid as instructed and based on a sluggish response I did nip off the plunger. While I had it open I also put in new carb float valve and checked to make sure it worked properly.
However, the problem remains the same. Engine will not run on its own, it will
start if boosted with starter fluid, run for a few seconds, then die. When engine is cranked over with its spark plug removed the compression blowing out of the plug hole is bone dry . The spark plug is also dry with no gasoline odor.
Taking into account that this motor had been in storage for more than a year,
(it had been working fine in its prior life) do you have any suggestions that I might try as a next step? thanks again, regards, from Bripatch.


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## jhngardner367 (Apr 5, 2011)

Ok,it sounds as if the main jet is clogged.The main jet is the one the solenoid closes off,so take the solenoid out,and use a thin strand of copper wire to clean it out,along with some carb spray,then put the solenoid in,and try to start it.If you take off the float bowl,and there's no fuel in it,check the inlet,on the carb,and the fuel pump,as well.just unhook the fuel line from the carb,pull the sparkplugs,and roll it over,while watching the fuel line.You should see it pumping out.If not replace the pump.


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## dangeroustoys56 (Jul 26, 2010)

Singles dont usually have a fuel pump, unless the tank is in the back- itd almost be worth it to replace the fuel line and filter- while checking the tank for debris - if the plug is dry, then sounds like the carb is due for a good cleaning .


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## bripatch1 (Jun 13, 2011)

I did the carb cleaning (on the bench) thoroughly including the fine copper wire
trick which was suggested and finished up by blowing the main line in as well as 
every thing else I could see out with compressed air (twice). No doubt it needed 
it. It appears now to be working but the same problem still persists.(Engine runs 
for a few seconds on starter fluid then dies). On another subject, I checked out
the motor when it came out of storage and removing the "OHV" valve cover
I found a small amount of old engine oil inside. I attributed to the fact that the
engine had been left laying in its side. Now I again find oil inside the cover (new
clean oil) and question whether there should be any oil in there at all. Is that
normal and to be expected, or is that another related problem?
Regards from Bripatch


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## jhngardner367 (Apr 5, 2011)

*carb*

Oil in the valve cover area is normal. As for the fuel problem, remove the float bowl,and turn on the fuel,briefly,to see if any fuel flows past the inlet needle valve.If it does,lift up on the float and see how big the gap is ,beteen the top of the float,and the carb body,when the float stops the fuel flow.It should be about 3/16ths,to 1/4 inch.If it's more, the float could be shutting of the fuel flow,completely,and not letting ANY fuel in.If with the float bowl off,andthe float just hanging,you don't get any fuel flow,either the fuel inlet is plugged,or the fuel line or filter is.


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## Country Boy (Mar 18, 2010)

Where is the fuel tank located on this unit? Had a Poulan Pro mower in the shop that a guy did a B&S 20hp twin to Kohler Courage 19hp single swap and he didn't install a fuel pump on the single. The B&S had it mounted to the shroud but the Kohler didn't have it. I had to drill out the boss on the engine cover, install a barbed fitting, run line from it out to the new pump, and then hook the pump to the fuel lines. Ran great after that. Before it was doing just the same as you describe. Run for a very short time and then die. It could get _some_ fuel because the tank (located under the seat) was full and the hose was just low enough that it could get a tiny amount of fuel to the carb.


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## dangeroustoys56 (Jul 26, 2010)

You want some oil in the OHV cover area - keeps the rockers working properly - no oil would indicate an issue.

Did you happen to check and see if the valves were opening/closing with the cover off? 

Double check and make sure fuel is comming thru the fuel line to even get to the carb. I replaced the section of fuel line on my tractors after the filter to the carb with clear fuel rated line - then youre totally sure youre getting fuel to it.


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## bripatch1 (Jun 13, 2011)

Thanks again for your posts on this problem which still does not want to go away.
First, the fuel tank is located up front allowing gravity feed and that is working (too well). I have changed the float valve and, after cleaning with carb spray and compressed air again, watched the float work with the bowl cover off, fuel shut off valve off and then on. With fuel on we get fuel flow and I can stop it by lifting up float by hand. It appeared to be stable. OK, but put the cover back on, allowed the fuel to refill the float bowl and started the engine. It ran a bit then died leaving a *puddle of gas in the air filter tray* (and a flooded engine). The thing is with the engine off the float valve seems to be working but with it starting up the valve stays open. 
The recommended dimension of between 3/16 to 1/4 inch is not what I found. Although difficult to measure accurately, I get more like *1/8* in. Is that enough? It might explain why I can stop the fuel flow by hand but its not happening in actual use. Its like the float valve is too short. I tried a different float as well. No luck. The float valve is new and to spec. The floats are used but they both " float". Maybe they're water logged? Any suggestions you might have would be appreciated.
Regards from bripatch1.


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## dangeroustoys56 (Jul 26, 2010)

At this point you might want to look into a carb rebuild kit and a new float - you mentioned it had sat on its side for a while- possible something warped out of shape. 

Youll also want to dump the oil and put fresh oil in the motor- gas in the oil isnt good for the motor....


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## bripatch1 (Jun 13, 2011)

Thanks , Dtoys 56 , right now I'm thinking about changing the float valve seat
since if is worn it could require the float needle valve to travel up too far before
it shuts off the fuel. Question: How is the seat installed, any special tools required?
I have the B&S part # for it 640577 and it can be ordered separately. any 
advise appreciated. Regards, Bripatch1


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## dangeroustoys56 (Jul 26, 2010)

Most float needle valves have a rubber tip- usually replacing that will stop leaking fuel ( rubber degrades a bit)- ive never changed the seat.


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## jhngardner367 (Apr 5, 2011)

Unless the seat is really bad,I'd listen to DT 56,and just replace the needle.


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## bripatch1 (Jun 13, 2011)

At this point I have a new float needle valve sitting in a new float valve seat which I put in yesterday and tested today. Still no cure to carb flooding which
I should clarify is more like a blowback (fuel "spurts" up out into the ail filter tray) when the engine starts up briefly before it dies.
I also have verified OHV valves setting at .004 and find no fault there. Makes me wonder if I don't still have an internal blockage somewhere else in the carb and if I should be considering buying a new one. Any thoughts appreciated. Regards, Bripatch1


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## jhngardner367 (Apr 5, 2011)

Are you sure the timing key isn't damaged/sheared?All it takes is a mark big enough to catch a fingernail,and it alters the timing.That would cause hard starting,blowback,and even backfiring.


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## bripatch1 (Jun 13, 2011)

Having trouble removing the flywheel's large (15/16) bolt to check the timing key.
 I have a half inch breaker bar on it but of course the flywheel turns with it in spite 
of the frozen hardware spray I used. Don't want to do any damage to the flywheel
teeth. Any recommendations? Thanks Bripatch1


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## Mickey (Aug 14, 2010)

Have an impact wrench?


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## bripatch1 (Jun 13, 2011)

No impact wrench, but I *was* able to remove the flywheel bolt by putting
a rope belt with a cinch knot tied on anchored to a 6x6 post and finding
a longer handle for the breaker bar. Now the flywheel refuses to lift out.
Any advise, other than the pulley which I don't have? regards Bripatch1


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## jhngardner367 (Apr 5, 2011)

There should be 2 threaded holes in the flywheel,that held the fan on.Use these to mount a puller,and make sure the threads of the crankshaft are protected(just thread the flywheel nut on,a few turns).I usually use a steering wheel puller,and it pops right off.They're inexpensive to buy(the pullers),usually around $10.00,or so.


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## dangeroustoys56 (Jul 26, 2010)

I use a large c clamp to hold the flywheel steady while removing the nut - i made a flywheel puller out of some angle steel , couple bolts and nuts - worked good till the center bolt broke. I bot a couple steering wheel pullers at a flea market for $5 each .


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## TractorWrangler (Jun 18, 2011)

Some times you can run the nut onto the shaft to protect the threads and hold up on the flywheel and gently tap on the nut. If its not rusted on or something that has worked for me. But you will have to be EXTREMELY careful not to damage the crankshaft. I have seen this done, and I have done it myself in a pinch. However, you can rent a puller from your local auto supply store to do the job properly.


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## TecumsehBriggs (Jun 17, 2011)

Air tools are a godsend! Use an air chisel with a blunt or pointed end. Lift up on the flywheel with a bar, then give a quick burst to the top of the crankshaft. Works every time.


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## bripatch1 (Jun 13, 2011)

Thanks to all. Best advice was to use the proper tool. I tossed the one which
I was trying build and used a loaner Flywheel puller that actually fit. Piece of 
cake after that. The flywheel timing key looked alright but I replaced it anyway
then reinstalled and tightened flywheel with (loaner) torque wrench. 
New question : Before I put the carburetor back on I want to be sure that I have it thoroughly cleaned in particular the mixture screw which I've never had out. This walbro carb has a black plastic (locking?) cap attached to the mixture needle valve which, due to its shape prevents the valve from unscrewing more than a 1/4 turn. I hesitate to force it not knowing whether its pressed or threaded on. Any advice ? Regards, Bripatch1

Found "Limiter cap" and Pt# 691333 in Illustrated Parts List but still don't see how it's attached.


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## Mickey (Aug 14, 2010)

The ones I've seen (mostly on cars) is pressed on. Typ adjmt screws have spline like groves and plastic cap meshes with these. No personal experience with your setup.


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## bripatch1 (Jun 13, 2011)

OK on the Limiter cap. I was able to trim it so that the mixture valve is now adjustable and is properly set between 1 to 1 and 1/2 turns from its seat. Everything put back together, the motor* does* start on starter fluid running perhaps a bit smoother that it did before (no carburetor blow back now) but then* still quits. *Any thoughts ? Regards, Bripatch1


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## HickoryNut (Mar 8, 2011)

jhngardner367 said:


> Are you sure the timing key isn't damaged/sheared?All it takes is a mark big enough to catch a fingernail,and it alters the timing.That would cause hard starting,blowback,and even backfiring.


I'm with jhngardner367 on this one. Get spares keys when you change. Don't ask why.....


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## jhngardner367 (Apr 5, 2011)

What happens when you start it with the choke on?will it stay running if you leave it on a little?


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## bripatch1 (Jun 13, 2011)

For jhngardner 367. Using starter fluid with the choke open gets it running. Closing the choke by hand does not seem to make any difference in run time before it quits. Also I get the same result using plain gasoline from a squirt bottle to start it. But even extra squirts of gas won't keep it running. I'd appreciate any other ideas you might have. Regards, Bripatch1


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## bripatch1 (Jun 13, 2011)

*Milestone* reached today!* Its Alive, *it starts and continues to run. It is 
charging the battery at about 13.5V and shuts down nicely with a kill switch we previously put in. This is posting #34 and the patience of those who hung in there giving support through 33 postings is greatly
appreciated. Thanks.
The problem and fix was in the carburetor float bowl where if you recall
we bypassed the solenoid shutoff to the main fuel inlet by nipping off
the tip of the valve. (We also put in a new carb float, new float valve,
and new float valve seat.) While doing all that I also noticed a vacant threaded hole on the inlet pipe and without thinking plugged it with
a small screw. (Boy did I screw up) because apparently it closed a breather hole and blocked the fuel flow into the Carburetor. DUH....
Live and Learn. 
Best regards from Bripatch1


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## fixit (May 22, 2013)

If the pin for the flote is down gas should come in if up it should shutoff. The needle could be sticking and causing the cab to flood.

Spotering and backfiring are cause by two much gass flow or timing.


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## timlab (Mar 26, 2021)

I'm hoping someone can tell me if I'm just dreaming. I have a kohler engine on my Husqvarna riding lawn mower. Today I replace the battery to see if she would fire up, as with a death battery she is dead. Anyway, I few turns of the key and pushing in on the brake pedal and she turns over, but will not start. I'm just now learning about lawn mowers as I'm a computer person, not a mech person. Anyway since she didn't fire up, I read some place that if you tap the Carburator a few times it should start unless there is something else wrong. So I touched the carburetor float bowl and noticed that it was a little warm to touch. I also noticed that there where wires going into the bowl float housing. Is it okay to be a little warm after trying to start it? I hope I can push this subject a little bit more and ask, what else could keep it from starting. It was in storage for a little over a year, with very little old gas in it. Could I use some stuff I got from Lowes in a little can to see if that will get it going? Any advise is great, but what is keeping me from even going this far is that fact that he bowl is a little warm to the touch. Thanks.
Dan


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## PaulD (May 23, 2021)

I have exactly the same problem with an almost new Huskee 7 speed. First time I've seen a carburetor with wires going to it. No way is a solenoid cheaper than a manual shut off in the fuel line! And it's a big reliability issue. Thanks to this forum I am pretty certain the solenoid is jammed because I can't move anything by hand.
Can't wait for the end of the small gasoline engine era! If manufacturers want to survive, here is what you have to do: Fuel injection and no carburetor!


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## PaulD (May 23, 2021)

bripatch1 said:


> I am swaping engines, from 12.5 hp powerbuilt OHV Briggs and Stratton (which is
> toast) to a 14.5Briggs and Stratton I/C Quiet OHV model 287707, on a 40 inch
> Murray riding mower. Question... Can someone tell me what the two wire
> connection to the carburator (Walbro 694918) which attaches to the carb float
> ...


I had never seen a carb with wires going to it either. There will be perpetual problems with that. Sounds like a dumb idea that will die a death. Don't buy a product with that kind of carb is the best way to accelerate its demise.


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