Oil leak- Concern?

[Carpedmman]

This past weekend I was in the bilge and noticed a quarter-sized oil puddle on my stringer under my Port engine. It appears there has been more oil leaking as it puddles and then runs down the stringer. I touched the underside of the engine until I found the source..It apprears that the oil is leaking from between the raw water pump and the fuel pump. Does this make sense? On this 7.4L engine the raw water pump bolts to the backside of the fuel pump if I'm not mistaken. There is a drain plug on the side of the fuel pump (I say fuel pump because that is what I believe it is...I could be wrong.) but this plug it tight and dry.

Any thoughts?

Any input is appreciated!

 

[mrsrobinson]

"oil is leaking from between the raw water pump and the fuel pump"

If you have the same set up we do your mechanical fuel pump is attached to your raw water pump. The fuel pump arm works off the pulley on your raw water pump. The arm lives in a reservoir of outdrive oil that is part of the pump. Not much, maybe less than a cup of oil. Over time the vapor from the fuel causes the seal to break down, thus outdrive oil drips on your stringer. It's a terrible set up.

The solution, a new raw water pump or rebuild the existing one making sure you replace the O ring seal behind the pulley. I replaced the port engine one myself on our boat. Worst job I ever did on the boat because of poor access. I paid the small mechanic to replace the starboard one. Do yourself a favor and replace the fuel pump while you are at it. Raw Water Pump was about $350 if I recall and the fuel pump was under $150 if I recall correctly.

I now pay the mechanic to replace the raw water pump impellers and housing (with a one unit housing) every other year. He drains and refills the outdrive fluid while he is at it. The plug you reference above is the drain plug for the outdrive oil.

These folks stock the parts: www.ebasicpower.com

http://bpi.ebasicpower.com/mm5/merc...nge_high= &srch_code=1&srch_name=1&srch_mfg=1

You may be able to find a better price as I recall paying around $350 for ours 2 years ago,

If you elect to pay the mechanic, buy the parts from these folks, much less. Our mechanic charges us 2 hours of labor for this job.

 

[Carpedmman]

Sounds like you hit the nail on the head as to the correct diagnosis of the problem. The only difference is that my engines are 180 degrees turned from your inboards so access is VERY easy. Looks like a do it yourself job with minimal problems. Another question is, Where is the fill hole for the fuel pump ? OK, Maybe a call to a mechanic would be a smart move at least for correct installation....

Thanks for your reply!

 

[mrsrobinson]

I cannot recall where it is. Order both pumps (fuel and raw water) at the same time and you should see it. Sounds like you already have some outdrive oil since you have outdrives. With good access it's an easy job.

Makes sure you get the gasket where the water pump mounts and where the fuel pump mounts.