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Cushman cart: OMC twin problem


WML13's Avatar
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03-27-16, 10:30 AM   #1  
Cushman cart: OMC twin problem

I have a 1963 Cushman golfster with an 18 hp OMC twin engine that was rebuilt about 10 years ago. It only gets occasional use on my farm. The other day I pulled into the garage and noticed that the passenger side exhaust pipe (it has dual exhausts) was laying down a pattern of black liquid onto the garage floor as it was running. A fingertip touch test revealed that it was motor oil spraying out. After shutting down the engine, a check of the dipstick showed the crankcase was way overfull and smelled like gasoline. If the fuel pump is overpowering the carburetor, I don't know how to fix it, and if there is something else I should be looking for, I could use some help there as well. The engine was starting and running great.

 
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03-27-16, 04:21 PM   #2  
Time to remove and rebuild the carb.
The needle floats sticking or trashed up causing the fuel to not shut off when the bowl is full.
Also make sure to change the oil, if there is none it would be a good time to add a fuel filter.
Use only non ethanol fuel and you will have far less future problems.

 
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03-27-16, 04:22 PM   #3  
It's not the fuel pump over powering the carburetor. It's probably the carburetor not stopping the fuel. I have not looked up that engine but take a look at the float and needle valve. The seat may be shot, the needle valve worn or the the float may be water logged with fuel.

 
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03-27-16, 05:33 PM   #4  
OMC Twin Problem

At least I can get to the carb easily enough. Darn thing ran fine all winter!

I will post back what I find!

Thanks!

 
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03-28-16, 06:04 AM   #5  
All it takes is one speck of trash to cause it to fail.
Gas powered equipment that is seldom used is far more likely to have fuel issues.
One simple cheap fix is to add a shut off valve in the fuel line.
When your done using it shut it off and let the motor run until it's out of fuel.
Ethanol fuel soaks up moisture from the air, gums up, will destroy fuel lines and rubber parts.

 
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03-28-16, 09:48 AM   #6  
I'm going after the carb as soon as I can!

 
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04-06-16, 06:36 PM   #7  
I ordered a carb re-build kit from a supplier that specializes in OMC parts. He said if the Carb rebuild didn't fix it, It was probably the fuel pump. (they apparently have a habit of rupturing and letting fuel into the crankcase. Well the carb kit helped a lot but I couldn't figure out why I was still getting black specks of fuel and oil coming from the passenger side tail pipe only. (duel exhausts, one pipe for each cylinder. The crankcase oil level was remaining constant. So I pulled the spark plugs and noticed that the bad side had a lot of carbon on it, while the good side looked normal. So I replaced them both and man! I started the engine and it took off like it was running away. Smoke filled the Garage and a big slug of unburned oily snot shot out of the right side tail pipe and hit the floor. Then engine rpms dropped back, and a slight readjustment of the carb got it running normally. I'm guessing that the plug on the right side had not been functioning properly for some time, and it let the gunk just build up in the muffler. Lesson: Change the plugs more often!
.

 
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05-01-16, 08:09 AM   #8  
Cushman cart OMC twin problem

Quick follow up. Engine starts and runs without ejecting any foreign substances for a couple of weeks. No changes in the oil level either. Lots more power with the other half of the engine in warp drive too.

 
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