94 Mercruiser 454Mag Fuel Pump Lube

[H20Dog]

94 Mercruiser 454Mag with a Bravo One Outdrive:
On this engine the mechanical fuel pump and seawater pump assembly mounts to the idler pulley bracket. What lube is used to service the fuel pump cam and when should it be serviced?

The water impeller failed so I took the whole assembly off and replaced the one piece seawater pump. I noticed a fill port for lubing the cam that drives the fuel pump. I didn't know that this was there. I've have always had a Merc dealer service my engine annually - well until this failure (have to watch the pennies these days) - and I know it has never been serviced since they have never asked about it. I can't seem to find it anywhere in my manual discussing this. Before I reinstall the assembly I'd like to service the unit if it is needed.

Let me know.

Thanks,
Bob

 

[Fun Times]

Re: 94 Mercruiser 454Mag Fuel Pump Lube

It's the same oil that you use in your sterndrive, (Mercruiser high performance gear lube +).

You should do it at the very least, every time you change the impeller.

Keep an eye out for excessive fuel in the oil.

 

[H20Dog]

Re: 94 Mercruiser 454Mag Fuel Pump Lube

Thanks for the heads up. Speaking of fuel in the oil. How much is too much? After your response I drained the oil but it was more like water than oil and as black as can be. The fluid also smelled more like fuel than oil. I know deep down it has never been changed. (I've always charged my local dealer with doing the complete annual and maintenance service and it has never been mentioned. That said the more I do on my own the more I find that hasn't been done that should have. Even so, no matter who does that work, it's my boat and my responsibility) I've included a pic for those who have asked for it.

 

[Don S]

Re: 94 Mercruiser 454Mag Fuel Pump Lube

The fuel means the diaphram is leaking in the fuel pump. BUT, and I really have no idea about this. Maybe mechanical fuel pumps all have a very minor amount of fuel leaking. I don't personally think they should leak at all, my problem is, I have NEVER removed one of those pumps and the gear lube didn't smell like fuel and was thinned down. But when those pumps are block mounted with an oil pan with 5+ quarts of oil and high oil temps to burn off the fuel that could leak, do we really know if they leak a little or not ????????????
That small reservoir that is not open to the atmosphere, may even cause fuel to collect, I have no idea.

Maybe replace the gear lube and check it again in a year and see what happens ?????

 

[HT32BSX115]

Re: 94 Mercruiser 454Mag Fuel Pump Lube

Don,

Isn't there a Mercruiser "kit" to replace that thing with an electric pump and just remove it once and for all?

There was also fuel in mine when I replaced the fuel pump.

I don't think a "good" fuel pump should leak either... I would think there might also be fuel in the clear/yellow hose to the carb if it was also leaking into the mounting port.