Crank mounted water pump retrofit?

[lwcwb08]

I recently picked up a 1974 Chris Craft Lancer with an OMC Stringer drive. It is in need of a water pump, and I am wanting to install a crank mounted water pump that I have off of a Volvo Penta set up. With this being said, my plan is to plumb it into the existing water line that is coming out of the intermediate housing. I am also going to remove the impeller in the drive, is it neccisary to remove any other components within the drive for this to work in the most efficient manner?

 

[Kainon]

Re: Crank mounted water pump retrofit?

I'd do as you said except I'd install a water pickup near the keel (with a shut off valve) and call it done I think, but I'm not that knowledgeable beyond that.

I wouldn't go through the drive fearing the crank pump would tear up quick unless you had some way of priming it, or having a closer water source.

I worked on a master craft ski boat and it had a pickup near the keel and close to the engine, I've work on the VP's too with the crank mounted pumps, but just kinda worries me about the distance and anything clogging it easily like the 3 cups of sand I took out of and older VP drive once.

 

[Don S]

Re: Crank mounted water pump retrofit?

You will have too many air (suction) leaks trying to pull water through the drive, they were never designed for that. You WILL need a transom mounted pickup or a through hull pickup to make it work.

 

[Kainon]

Re: Crank mounted water pump retrofit?

you can trust me when I say, trust Don, I've read alot of his posts, and I would agree with him especially in this instance, but the choice is yours. Worst case is you'll overheat the engine and definately shred a couple impellers blocking a water passage or two...

 

[lwcwb08]

Re: Crank mounted water pump retrofit?

I completely agree, I want to do this right the first time around. What type of thru hull am I looking for here? I don't think a regular old thru hull fitting will work if i'm not mistaken. Would you be able to provide an example for me Don?

 

[Howard Sterndrive]

Re: Crank mounted water pump retrofit?

I want to do this right the first time around.

why not just change the impeller in the drive then? nothing flows water like those big ol' stringer impellers... they're huge... $30 or so for the original equipment from Evinrude.

If you think you're going to simplify maintenance, think again.
If you don't grease the splines of that vertical shaft in the water pump in the drive, you'll be paddling that Lancer.
If you search, you'll find 100 posts on this forum about stripped water pump spline shafts on stringers resulting in loss of propulsion - all due to no grease in the splines because the impeller wasn't regularly serviced.

If it's because you're in sand bars all the time and need to access the impeller at sea, then forgive me. (but still don't forget to grease the w/p shaft splines every 2 or 3 years)

 

[Howard Sterndrive]

Re: Crank mounted water pump retrofit?

plus...and this part is all just an educated guess:
the upper does not share oil with the lower on those drives, so when on plane, the upper is not under water and not cooled.
I suspect those gears might run hot with no water going through the upper.
that might be less of an issue on a boat with through hull exhaust.. not sure.
but hundreds of HP going through a small right angle gearset in about a quart of oil doesn't present much opportunity for cooling.
I know other drives do it - but sharing oil upper to lower...
a drive shower might be the answer.

 

[lwcwb08]

Re: Crank mounted water pump retrofit?

That's one of the reasons I wanted to do the conversion, I will be mostly running in the intercostal here with occasional trips out to sea and want to be able to access the impeller just in case it gets clogged with sand. Never thought about the cooling issue in the drive, anyone else have any expiriences with this? It does not have thru hull exhaust....