gas in my oil?

[ffmedic]

I just changed the oil and when I did I found it to be very thin and almost watery. firsr i thought I had water in the oil but I realized that it is not water but gasoline? Why would there be gasoline in my oil. My gas tank is bone dry it appears that some how all of the fuel that was left in my gas tank is now in the oil pan. is there a gasket in the fuel pump that could have gone bad and allowed this or is this a major problem for the engine? Any help truly would be appreciated.

[Don Moyer]

This could be a very dangerous situation. The most common (almost the only) way that large amounts of fuel can get into the crankcase is through a leaky mechanical fuel pump diaphragm. I suggest you inspect the bottom of the pump for evidence of fuel droplets and then try to pressurize the fuel line leading to the carburetor by working the priming lever of the fuel pump. If the pressure in the diaphragm bleeds off quickly (within a few seconds) it would confirm a leaky diaphragm.

Don

[ffmedic]

I just ordered an electronic fuel pump to replace the mechanical pump. This should bypass the mechanical pump thus solving the problem. Am I right with that thought?

[ndutton]

Be sure to get the mechanical pump blanking plate too.

[roadnsky]

Be CAREFUL

ffmedic-
Did you determine the source of the fuel leak?
Don is correct in that oil and gas make for a very dangerous cocktail!!

Yes, getting the electronic fuel pump will "solve" any issue with your mechanical.
BUT, I'd strongly encourage you to check that diaphragm as Don has instructed.
You need to KNOW that you know where the leak is...

[ffmedic]

With the electronic pump wont I just completely eliminate the mechanical pump thus making the bad diaphragm a mute point?

[ndutton]

With the electronic pump wont I just completely eliminate the mechanical pump thus making the bad diaphragm a mute point?

Well, yeah, but what if it's not the pump? I think we're all about 95% sure it is but just to be certain . . . .

[ffmedic]

after going through the fuel system this afternoon I am about 99.9% sure that the problem lies with the fuel pump. Hopefully I can get that pump replaced soon and be back out sailing by next weekend.

Thank you everybody for your insight it was very helpful

[sastanley]

ffmedic,
thanks for the update..a follow up is always appreciated so future forum members can learn from your experience.

I still have a mech fuel pump and rely on that membrane!

[67c&ccorv]

I just ordered an electronic fuel pump to replace the mechanical pump. This should bypass the mechanical pump thus solving the problem. Am I right with that thought?

The short answer is "No".

A properly maintained mechanical fuel pump is one of the most simple and effective means to supply fuel to the Atomic 4.

[ndutton]

I still have a mech fuel pump and rely on that membrane!

FYI Shawn

http://cgi.ebay.com/ebaymotors/UNIVERSAL-ATOMIC-4-FUEL-PUMP-REPAIR-KIT-_W0QQcmdZViewItemQQhashZitem335dbcbc4fQQitemZ220615982159QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear

[ndutton]

A properly maintained mechanical fuel pump is one of the most simple and effective means to supply fuel to the Atomic 4.

ffmedic,

The flip side of that same coin is an electric fuel pump can have side benefits with very little additional plumbing (a valve and a little hose). Here's the thread discussing it, starting around post #20 or so:

http://www.moyermarineforum.com/forums/showthread.php?t=3788&highlight=fuel+polishing+system

[thatch]

Some forensics please

ffmedic,
Since there are still many mechanical pumps being used would you mind disassembling yours (assumming that the diaphram has failed) to see if you can determin what caused it to fail. In other words, did the membrane just rip or did it shribble up like it was being affected by the alcohol laced fuel we are currently using.
Tom

[hanleyclifford]

scary thought

Tom - You have raised another barracks issue. If a diaphragm in a fuel pump could be affected by the ethanol, what else in the engine do we need to worry about being attacked by ethanol?

[thatch]

"Not a swell situation"

Hanley,
The marine industry has adjusted their fuel line, fuel tank and fuel system related parts "materials" recently to acommodate the alcohol situation. The parts that are still out there like older fiberglass or "plastic" tanks, fuel lines, mechanical fuel pumps and fuel regulators are areas that we should watch for alcohol deterioration. A couple of years ago I had an aftermarket fuel regulator in a pickup truck fail and I was amazed, upon disassembly at how "melted" the diaphram was. Fuel lines, in particular, tend to just "swell" themselves closed gradually without actually leaking but definately affecting fuel flow which could explain some "power loss" at higher RPM situations.
Tom