Is it possible

[lovestocruise]

I have a 97 330 Dancer with twin I/o's and 454 Big blocks with 4 barrels.
I was told that I need to change my fuel pump as the fuel is mixing with the oil.
I thought that both are totally seperate functions.
Has any had this problem and is it possible to have fuel mix with oil?

 

[Alegria]

Hi! I have your set up on my engines. You most likely have the fuel pump and water pump in the same unit. It's a mechanical fuel pump that needs a special kind of grease/oil lubrication to keep it running in top shape. My surveyor said to lube this every other year depending on use. I believe there is a small cam attached to the pump and there is a reservoir for the oil/grease? That may be leaking and that may be the 'oil' they are referring to. Its a salty part to replace, they replaced mine on my port engine this year and the part alone is around $500.

Not sure how motor oil would be mixing with the fuel. Not saying it couldn't but I am not sure how it would be...

Just a guess there on my part about your pump!!

 

[Quint4]

The fuel pump can be replaced separately from the water pump. I am replacing mine in the Spring as I noticed fuel in the sight tube which indicates a failed diaphragm. I am finding them for about $150 on the net. I do not see how this would have anything to to with fuel in the oil.

 

[my3sons]

the fuel pump mounts on top of the sea water pump. on the sea water pump shaft is a cam that operates the fuel pump rather than the pump being mounted to the block as it was in the automotive application. The sea water pump is lubricated with drive oil, the same heavy duty mercruiser drive oil that is in your outdrives and "I.V. bottle".
If a diaphram goes bad, fuel will leak into the pump oil and should also be seen in the sight tube as mentioned by Dave.
The fuel can not get into your motor oil from the fuel pump or water pump. The water pump has a plug in the side, the same size and type as the drain and fill plugs on your outdrive. It is not a bad idea to change that oil yearly. If you have the pump with one plug , you will have to suck the oil out with a small pump or similar. some pumps have two plugs, drain and fill. If you have that you are all set, just drain and fill to top of fill plug. If you remove your entire pump to change the impellers, then just dump the oil out of the pump body while it is off the motor. The oil that I would drain from my pumps on the 330 and 290 would always smell of gasoline although there was no problem with the fuel pumps. I think that over time, the fuel would very slowly permiate into the pump oil through the diaphram.:huh:. Check the oil in your pumps, if it is more gas than oil, you might have a problem, otherwise, just keep the oil changed every year and as long as there is no fuel in the sight tube, I would say you are OK. Hope this helps
P.S. As a side note, If any of you guys are looking for a spare seawater pump, I have the one I used to carry as a spare for sale. Also have an impeller kit for the 7.4's that go with it. No reasonable offers refused, I can't use 'em on 8.1's:smt001