john deere 318 with P218G Onan engine

Kermit Vetter · Nov 4, 2019

Just installed a new carburetor and pulse type (AM107870) fuel pump. After first start, engine ran great but then got a large amount of oil and gas mixture blowing up out of the crankcase breather. I had just changed the engine oil and had the right amount in it. Now its way over full. I drained out over a gallon, so gas is getting into the crankcase but how? Thru the carburetor or from the pump vacuum line?
I need help!!

Bob · Nov 4, 2019

Is there gasoline in the hose that connects the (stupid) pulse-type fuel pump to the engine crankcase?

Lose that (stupid) fuel pump and install a low pressure electric fuel pump.

Billy Shafer · Nov 5, 2019

Bob I agree get a low pressue pump 4 lbs max. Can't say what I really think of them pumps. I went to the factory school in 1980. We had a rather heated talk about them.It was called the pulse pump. But we had other names for them.

kencombs · Nov 5, 2019

Those pumps are simple and work. Used by every engine maker, Honda, briggs, Onan etc. But, an electric is still better IMO. That said, a new pump shouldn't do that. how long did it run after the new pump?

Kermit Vetter · Nov 5, 2019

I ran it for a few minutes then shut it off to make an adjustment on the drive mechanism. When I restarted it and ran it a little more the oil/fuel mixture started blowing up ou of the crankcase breather tube.
So you think the problem is with the new fuel pump? Like i said the oil level was way over full. A lot of gas had been pumped into the engine.

Kermit Vetter · Nov 5, 2019

So you think the new fuel pump is pumping gasoline into the crankcase? I haven't removed the hose to the carb yet.

Kermit Vetter · Nov 5, 2019

So you also think that the fuel pump is my problem and is pumping gas into my crankcase. It has to be either that or the carburetor, but it ran great before it starting blowing the oil/gas mixture out of the crankcase breather hose.

kencombs · Nov 5, 2019

Is this the pump that mounts on the engine cooling tin with one connection on the back? The two line from the tank and to the carb? If so, it must be bad since there is no way to install the lines wrong and still run, at least I don't think so...

And, the carb overflowing that bad would run terribly.

I think the pump supplier owes you a new one.

Kermit Vetter · Nov 5, 2019

Yes it is. It has 5 connections, one that connects to the crankcase behind the flywheel cowling, one that connects to the line from the fuel tank and one that goes to the carburetor. They're marked in and out. the other two on the bottom are capped off. I'm thinking seriously of installing an electrical fuel pump. That would eliminate the vacuum issue. Then the only way gas could get into the crankcase is thru the carburetor. I don't think there is a problem with the new Carburetor since it ran great after I first started it up.

Billy Shafer · Nov 6, 2019

If it was the carb it would not run very well.Those vacum pumps were known to leak. Most of the time into the oil.

Kermit Vetter · Nov 6, 2019

Thank You, I have a low pressure electric pump that I tried on my riding lawn mower but the pressure was too high. I'll see it will work on this John Deere.

DearMe · Nov 9, 2019

A pulse pump costs $45 to $60 depending on where you buy them. They are junk. A new electric fuel pump 2 lbs pressure costs $10 to $15 on Ebay. Much better pump.

Kermit Vetter · Nov 11, 2019

I've found a couple of electric pumps on Ebay that are 2-4 PSI but all have 5/16' connections. All the fuel lines are 1/4". Guess you can buy reducer fittings.

john deere 318 with P218G Onan engine

Kermit Vetter

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Bob

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Billy Shafer

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kencombs

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Kermit Vetter

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Kermit Vetter

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Kermit Vetter

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kencombs

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Kermit Vetter

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Billy Shafer

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Kermit Vetter

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DearMe

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Kermit Vetter

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