Bad New - Gas Everywhere

[MALandscaping]

So, in a different thread the other day I wrote about the Robin 22hp motor surging and me thinking it was the fact that the oil cooler fan wasn't coming on in a mid-80s degree day. Well, I adjusted the valves, cleaned the plugs, filled with gas and ran it about 10 minutes yesterday, still had some surging.

I know vapor lock was a suspect, as was maybe coil issues (both plugs had strong spark). Well, came home today and whole house smelled like fuel. Check the garage, and the previously-filled PT gas tank is half-full. Gasoline is literally is dripping out of the rear muffler (older style that is at the back of the motor within the engine bay). I then pull the dipstick and gas comes out of the dipstick hole like a tidal wave. In retrospect, it did seem like it consumed more fuel than usual the other day (but not drastically so). I even checked the oil level when it first surged and smelled it and both the level and smell were normal. I did notice that after shutting it off last night it sounded like the carb was still pumping fuel. Could this just be a failed fuel shutoff switch? Or am i screwed (head gasket, etc.)? Thanks for your help.

 

[BobRip]

My guess is the fuel pump is leaking gas through it's diaphragm into the oil. I have not had this happen on my Robin engine, but it did just happen to my Chevrolet. This is just a guess. Is this your original fuel pump?

 

[J_J]

Do you not have a manual fuel shut off inline to the carb. If the inlet needle valve and seat are not perfect, fuel will overflow into the engine.

I have had Kohler and Briggs carbs leak gas into the oil and I have had water in the oil.

I now always check the oil level to see if it is correct.

Drain the oil mix and start over.

Fix that needle valve and add the manual shut off valve.

If you have a solenoid on the carb, it is probably an anti-backfire device.

 

[MALandscaping]

Thanks for the replies. Not sure how al Robins are, but mine (an EH65) has a solenoid fuel cut valve. It is likely the original fuel pump, and I have not yet installed a manual shut off. I only have put about 20 hours on it since I bought it, but generally try to put a shut off on all small engines...at least ever since they started putting ethanol in gasoline. Rode a lot of dirt bikes and found the ethanol constantly clogged the needles with white debris. Running the carbs empty seemed to drastically reduce the need to rebuild/dismantle and clean the carbs, so I do it on the bikes, generator, pressure washer, mower, etc. Apparently I waited 20hrs too long here.

Anyway, sounds like it could be three things: faulty fuel cutoff solenoid; stuck float/needle; or bad fuel pump/diaphragm. Is there a good way to diagnose one from the other before I pull apart the carb?

Also, I know this is probably a dumb question (but I am a novice to hydraulic equipment), is there any chance fuel got into the hydraulic lines? I suspect no because the systems should be completely sealed. Thanks again.

 

[KMA]

Yes, no chance of fuel in the hydraulic lines.

 

[J_J]

Thanks for the replies. Not sure how al Robins are, but mine (an EH65) has a solenoid fuel cut valve. It is likely the original fuel pump, and I have not yet installed a manual shut off. I only have put about 20 hours on it since I bought it, but generally try to put a shut off on all small engines...at least ever since they started putting ethanol in gasoline. Rode a lot of dirt bikes and found the ethanol constantly clogged the needles with white debris. Running the carbs empty seemed to drastically reduce the need to rebuild/dismantle and clean the carbs, so I do it on the bikes, generator, pressure washer, mower, etc. Apparently I waited 20hrs too long here.

Anyway, sounds like it could be three things: faulty fuel cutoff solenoid; stuck float/needle; or bad fuel pump/diaphragm. Is there a good way to diagnose one from the other before I pull apart the carb?

Also, I know this is probably a dumb question (but I am a novice to hydraulic equipment), is there any chance fuel got into the hydraulic lines? I suspect no because the systems should be completely sealed. Thanks again.

The fuel pump would not have anything to do with fuel leaking into the engine.

The fuel needle plunger is the main culprit, or corroded seat.

I believe the fuel shut off solenoid valve only shuts off fuel to the main jet, whereas the idle jet comes form the bowl supply, and if the fuel needle is leaking, you can see that the fuel will flow into the bowl and then into the crank case, When that is full, it might run into the exhaust system and out.