Onan CCKB first run

This is the Onan CCKB that required a 12 hour round trip to purchase, engine sat for the past five years in a garage.

Previous owner replaced this engine because of fuel problems, I've already discovered the reason for the carburetor constantly dripping fuel.

He had replaced the mechanical fuel pump with an electric which is putting out way too much pressure the book calls for 1.5 psi. I'll install a pressure regulator to fix the problem.

I'm just running the engine with what fuel is in the carburetor, with an open exhaust don't want a fire.

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Edited by rustydollar - 15 Aug 2017 at 12:50pm

Well well the after market electric fuel pump that came with my recent purchase looks identical in every way to the Onan OEM pump.

Grabbed a spare pump from a generator and it tested out at 2 psi the after market came in at 5 psi.

Incidentally there's a filter screen inside the electric pump, the bottom cap has a type of cam lock easily removed.

Now would be a good time to get an ultra sonic cleaner and some new throttle shaft bushings, it's going to be an early winter. I need that snowblower ready for all that snow I'm expecting.



Edited by rustydollar - 15 Aug 2017 at 2:59pm

Simplicity engineering at its best, on the carburetor used on the 9020 you'll find an extra fitting with yet another fuel line leading back to the fuel tank.

Essentially this is a pressure regulator that keeps the fuel supply to the carburetor maintained to  constant 1.5 psi.

Excessive pressure delivered from the fuel pump is bypassed through the orifice back to the tank,  from what I'm gathering on this is that the lower pressure exerted onto the float and needle valve prolongs its life.

The bypass orifice on my carburetor was plugged solid.

If anyone has an opinion that differs from mine I would like to hear it.




Edited by rustydollar - 17 Aug 2017 at 11:37am

Tracy Martin TN wrote: That is what it is for. I normally use an electric pump. I tee the inlet line, run a hose to a cutoff valve then to return tank. You can use valve to get pressure and volume regulated to good running specs. HTH Tracy

On the original Max 9020 engine failure of the manual fuel pump diaphragm leaked enough fuel into the oil to thin it out causing the engine to smoke really bad. Previous owner thought the engine was kaput.

He removed the engine setting it on the ground to where it seized up from neglect, when I disassembled the engine could smell the gasoline in the dilute oil.

It is from this discovery that I have also chosen to use an electric fuel pump.

DiyDave wrote: The mechanical pump isn't too bad to replace, I think I did it once, on a gravely 816.  You might wanna price out both ways, to see which is cheaper...

Your probably right in that the mechanical pump is cheaper to purchase, the real problem is if a small hole occurs in the diaphragm with the fuel tank mounted slightly higher than the pump.

Fuel will siphon then leak into the crankcase through the damaged diaphragm then dilute the oil.

When I got my 9020 the previous owner had gotten the 'official' Onan electric fuel
pump kit from Cummins,pretty neat set up but for $300 I guess it should have been.

Sitting on the seat the rear engine bolt on your left hand side is a tricky one, here's the factory bolt they used to keep it from spinning on you while tightening the nut from the underside..

I think they must have installed the bolt first into that particular hole before installing the engine into the frame.

Easy enough to replicate.




Edited by rustydollar - 25 Aug 2017 at 12:58am