reading about seawater driven fuel pump - now paranoid
 

Hi, so, I was reading on the failures of the cam in these things and I'm all worried.

What will cause them to fail? How often do they really fail? Can you tell me anything you know about them?

I doubt you'll wear anything out before the gaskets melt away from alcohol fuel. Been my experience anyway.Check the little 4-6 oz oil reservoir, when it's full of fuel....there ya go. Good luck.

I change the impeller and oil once a year. I use outdrive oil.

welp, now to sound like an idiot...

How do you add oil to the cam that drives the pump?

Take fuel pump off and filler up !

oh, really, that simple. Thats what I was thinking.

So, what happens if there is gas in there?

Empty it out and refill with oil. They always have fuel in them.

alright, cool. Feeling a little better.

Thanks!

Yep.

Fuel in the res means the diaphragm has failed...and you're running 87 octane instead of the 90 weight oil for pump lubrication.

I'm not arguing but I've never heard "they all have fuel in them". Mine doesn't.

It seems to be normal from reading this thread: http://www.offshoreonly.com/forums/g...el-pump-4.html

the boat I just sold had fuel in the oil in the seawater pump. I replaced the fuel pump because of the fuel. a few months later.....fuel again. I was told it is "normal" for them to seep. most mech pumps are mounted to a engine block and lubricated by engine oil. a few drops of fuel in 5 quarts of oil isn't noticeable when its changed every few months. a boat with a fuel pump on the seawater pump contains very little lube. a few drops a month adds up to a noticeable amount. since learning this, I always change mine when winterizing for the year.

I think merc calls for a 25 hours service schedule on these pumps. Its common because It's a poor design, and guys dont check/service them on that schedule, but it shouldn't leak.

Its prolly wise to have the shaft seal and dia replaced while its out instead of just adding oil. Like was mentioned its a small amount of 90 wt drive lube, a little gas mixed in can't be good long term. Ethanol is only making it worse.

I threw my stock pump in the trash and installed an electric fuel pump . End of problem and has lasted 13 seasons now . Holley black label with the Teague 7# spring .

Our old 96-97's have the VST. not sure how to go about all that mess. It would be nice to just run the old school sea water pump and ditch all that other crap.

Yes found this out when mine went a month ago , really had no idea it even existed . These things aren't cheap either best I've found is on eBay 650 $ for pump and fuel pump ! Boating lol!!

one of the most B/S setups merc came out with...although they have had many...

Yeah, I've found it very typical for the oil to be diluted with gas on these pumps. When I change out the sea pumps, at least every other season.(approx 100 hrs)) I drain/refill w/gear lube. No major issues as long as it's changed. -From my experience, every 25-30 hrs would be overkill, just do it when you're swapping out the impellers.

Well if anyone ditched this setup and still has it i might be interested because i have a holley electric pump and went through two of them in two seasons

Here's a suggestion right outta left field to ponder...

I'm a life long 2 stroke dirtbike nut. For decades, been running Castor Bean oil (Klotz Ben-ol) in my pre-mix as castor has exceptional film strength and mixes with gasoline. Since it's proven that there is a fair amount of fuel migrating through the fuel pump diaphram, Castor oil could possibly be the best lube for this application????

I have two of the stock pumps both like new . Where are you mounting the electric pump ? You must mount them low because they are a pusher not a puller . Incorrect mounting position will burn them up in a hurry .

Mine failed because the front seal checked out and the pulley slung my lube all over the bilge, this caused the pump's foot to wear to nothing. $55 for a new pump, $35 for new bearings and seals and I'm back in business.