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Lawn mower fuel pressure?


rusty ol ranger

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My old yazoo has a K582 kohler (23hp, Opposed twin, cast iron).

The fuel pump quit, ive tried a couple different pumps but all thats available are chinese ones. Ive tried 3 now and i cant get more then a trickle of fuel from it.

I bought a rebuild kit but the one on it also wasnt OEM, so rebuilding it didnt go well.

Fuel lines are new, so i dont know if what drives the pump is wore or what.

My question is what PSI do these run at? I know a carb on a vehicle is around 6psi IIRC. I found some universal 12v pumps that run from 2.5-4psi...think that would be to much? Not enough? Just right?

Opinions please.
 


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I don't think you would need much pressure, it would be volume that matters.

Motorcycles use a gravity fed fuel system.

EDIT Old carbureted ones any way.
 

rusty ol ranger

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I don't think you would need much pressure, it would be volume that matters.

Motorcycles use a gravity fed fuel system.

EDIT Old carbureted ones any way.
Right...im actually more worried about over gassing it rather then starving it.
 

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It's low, don't think it's a psi... if you can't get fuel, pull your fuel tank and rinse it out backward, most have a screen in the outlet melted into the plastic and yours is probably plugged... you could test that, put the fuel line low and get it flowing, it should flow freely, if not then there's a restriction in the tank... my tractor has a big metal tank and there was a wood chip in the outlet that had bounced around long enough it had taken the shape of the outlet and blocked off fuel...
 

rusty ol ranger

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It's low, don't think it's a psi... if you can't get fuel, pull your fuel tank and rinse it out backward, most have a screen in the outlet melted into the plastic and yours is probably plugged... you could test that, put the fuel line low and get it flowing, it should flow freely, if not then there's a restriction in the tank... my tractor has a big metal tank and there was a wood chip in the outlet that had bounced around long enough it had taken the shape of the outlet and blocked off fuel...
Mines got a big steel mounted tank on the side. It has to get sucked up through a steel tube about 1.5ft in length.

I didnt think about removing the tank and trying that. However i do know i can suck fuel up by mouth with very little effort. I shined a light down into the tank and it looked about spotless. But ill give it a try
 

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If you can suck fuel then it should be ok, the other thing is the impulse line for the fuel pump, I don't remember where they go but make sure the line is reasonable, it either goes to crankcase pressure or intake manifold pressure probably on one of the two intake tubes so it pulses...
 

rusty ol ranger

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If you can suck fuel then it should be ok, the other thing is the impulse line for the fuel pump, I don't remember where they go but make sure the line is reasonable, it either goes to crankcase pressure or intake manifold pressure probably on one of the two intake tubes so it pulses...
This one actually is lever drive like a vehicle.
 

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> Ive tried 3 now and i cant get more then a trickle of fuel from it.

That would tell me it is YOU and not them ;)

PSI is very low, it is basically gravity fed at that point. Unless the engine is running 1800-3600 RPMs all you will get is a trickle because that is all that is needed to fill the sediment bowl so the engine vacuum from cranking can draw the fuel out into the carb. Cranking only produces a minimum amount of vacuum vs. running at 3600 rpms.

From my experience fixing the larger 22 HP FR651 twin Kawasaki ZTR mowers, riding lawn mowers, and such.

First, change ALL the fuel lines and vacuum lines.

Then check that the fuel cut off solenoid at the bottom of the carb is functioning correctly with key on. Take it off and watch for the plunger to pop off when in the VERTICAL position, just as if it was attached.

If it still does not pump gas, then check the valve lash and do it according to spec. Then do a compression test. I like to do a compression test before and after, which will tell you how successful your valve adjustment was. I found this handy for the Ford 2.8L too.

I have had no problems with the knock off JD/Kawasaki fuel pumps from Amazon, your mileage may vary. If you have a 3 connector fuel pump you can always go to a JD dealer and get one that is OEM Kawasaki FR651. e-replacements only sells OEM parts and I have used them with success too.

Not a 2 or 4 cycle small engine expert, but, I buy 2-6 riding mowers/tractors a year to fix up, use, or sell. So, I have seen a thing or two, and this is how I approach them BEFORE replacing the fuel pump.

If you want to test the pump, after all that, you could run it on starting fluid and carb clean for a few seconds. I would not because the risk of engine damage, but, just throwing it out there.

$0.02
 

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Fuel filter ? Also, My buddy is a service manager at a mower shop and he said he has to re-drill out a lot of the orafices in the carbs from china, the orafices don't match up to the specs claimed so he has to widen them with micro drills so the fuel flows better....
 

rusty ol ranger

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I actually got the electric pump on and hooked up and its running good now. Untill something else breaks.

I love the mower...but it was a mistake buying a somewhat low production mower built by a company that went under in 1994
 

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I actually got the electric pump on and hooked up and its running good now. Untill something else breaks.

I love the mower...but it was a mistake buying a somewhat low production mower built by a company that went under in 1994
The things you learn after the purchase...
 

rusty ol ranger

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A legend to the old man, a hero to the child...
The things you learn after the purchase...
I bought it cauae it was big, cool looking, ran good and has a K582 kohler. That bastard will mow through a fridge.

Now i gotta get the old gravely 18h going.
 

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