Logo
FULL SITE MENU

Lots of gas in oil

J

Jtomei

New member
about 3/4 quart of gas in my oil in 10 minutes running on the hose. 1995 50hp mercury 4!stroke. The fuel pump seems to check out could It still be defective and seem fine? The engine ran great last time out no problems at all haven’t taken it out since I found the gas in oil.
 
Last edited:
You didn't say what engine. On older automotive gas engines if the fuel pump diaphragm ruptures you will get gas in the oil.........the diaphragm is moved by a plunger driven off the engine proper (crankshaft protrusion as I recall).....so you have gas on one side and engine oil on the other. Since the pump sucks and blows fuel, with a punctured diaphragm,on the blow half of the revolution some of the fuel goes through the hole into the crankcase.
 
Jtomei said:
about 3/4 quart of gas in my oil in 10 minutes running on the hose. The fuel pump seems to check out could It still be defective and seem fine? The engine ran great last time out no problems at all haven’t taken it out since I found the gas in oil.
Click to expand...
1995 mercury 50hp 4 stroke sorry guys
 
Remove the fuel pump from the head with the hoses still attached if possible. Otherwise, reattach them after removal. Then while depressing the pump shaft (to simulate the pump in operation) pump the fuel line ball. I'd expect to see fuel leaking from pump shaft.
 
Back
Top