View Full Version : Where can I get a sump style water cooling system

08-17-2016, 08:10 AM
Hi all I have a 1970 donzi ski sporter 16. Right now is just has what I assume is the stock style external crank driven water pump that bolts on a plate and then is mounted to the front of the engine. Also my water pickup is still down on the bottom of the out drive. My problem is after getting on plane for a little while I loose prime and i loose water flow to the exhaust and it burned up my rubber exhaust pieces. The engine doesn't overheat. I know the temp gauge works correctly. As it overheated a month ago and I pulled the heads off and did the head gaskets and cleaned the water passages out in the block.

So my friend has almost the exact same boat but it has a sump style pump that there's a hole ported in the back of the boat with a metal tube bent 90* and then it's some kind of pump inside that pulls the water in. His system works amazing but we don't know what brand it is or how to go about finding one for mine.

I don't want to pull the out drive apart and re do the seals as I'd much rather have the other style system with less chance of dragging it on the bottom and sucking up junk.

Any ideas on what the system is called that I'm looking for guys?

Pat McPherson
08-17-2016, 08:49 AM
Not quite sure I understand what you are looking for. It sound like you have a crank driven pump that pulls sea water in thru the outdrive. It also sound like the flow of your system is low and not providing enough volume. The most likely issues is that there is a blockage in your drive or the pump/impeller is shot.

To help diagnose the problem, please tell us what out drive and what engine you have. Is there a circulation pump on your engine or some sort of crossover? Do you run a thermostat? Pictures might help.

If you are looking to move the pickup from the drive to the transom, there are threads here guys will point you to.
If you are looking for a new seawater pump, my suggestion is to stick with a crank driven pump.

08-17-2016, 09:25 AM
It is the original HM 302 in the boat.
Running a 160* thermostat.
Volvo 250 outdrive

It's not a blockage but it does seem to be low volume.

Could someone point me in the direction of a good high flowing crank driven water pump that would work for me? And I assume after installing that I could just move the hose attachment point from the outdrive to the spot in the hull where I would like to bore through and have the water pickup there instead.

08-17-2016, 09:41 AM
George Carter, 70Donzi16 is looking for you.


Just Say N20
08-17-2016, 10:19 AM
George Carter has a water pickup on his transom. I used the same one on my 1967 Donzi 16.

Unless something is wrong with the crank mounted pump, I don't believe that is the problem. My engine had a crank mounted pump and it worked great!

This is NOT the transom mounted water pick up I used, but similar: http://www.rexmar.com/page168.html

Another type from Teague Custom Marine: http://teaguecustommarine.com/em0011/ss-transom-water-pick-ups.html

This one is similar to what I used: http://www.lathammarine.com/sea-strainers-water-pic.htm#1

08-17-2016, 10:54 AM
the HM crank driven pump "IF" it is in good working order ,good seal ,good impellor will cool a 302 no issues

possible causes for burnt hoses

1. blocked or plugged risers both water outlet or intake on the riser

2. air is getting into the system thru the drive or some place else when on plane then I would look at drive seals

a transom pickup is not a bad idea anyway even with the HM pump

the HM jabsco pump is no longer available but a johnson replacement can be used with some mounting engineering. I have seen this issue far too much with HM boats lately . the pump must be perfect the wear plate is worn to the point where the water just passes by the impellor blades cause they are not flush with the plate I had mine milled cause both sides were worn the ol'timers just flipped the plate over so mine had be worn on both sides.

look at water flow, steam do you have steam? one side both sides?

oh forgot about the lovejoy spider and the teeth on the pump and pulley if they have been metal to metal for any time they may make the pump spin slower cause it slips a little

08-17-2016, 10:58 AM
oh forgot about the hoses the one on the drive or the one to the pump could be collapsing under load like sucking a straw shut

gotta love cooling issues


08-17-2016, 11:24 AM
The engine is not overheating.
Even on plane for 15-20 mins

Steam more so from the passenger side exhaust at the transom than the other side but both ended up melting the rubber.

I smelt it when running and came off plane but it was too late. Leaned back over the hatch and saw the passenger side had no water flowing out of it but driver side did a little. I pulled the hose off at the thermostat housing and it was just pushing steam out at first and then started pumping clean good water. I hooked it back up and it flows well again out of the end of the exhaust. I don't believe either of my riders are plugged at all.

But I do think that the seals in the drive or the water pump are the culprit.

But that is why I would like to do a transom mounted style water pickup. I do not want to mess around with pulling the drive apart to replace the seals when I am not fond of the setup to begin with.
So I believe with what I am reading I can make my own transom mount up and just move the water pickup hose and run it from the transom to my current crank driven water pump which I do want to replace as well just for good measure.

08-17-2016, 11:54 AM
Thank you for the links on the transom mount water pickups. Now all that's left is me trying to figure out where to find a crank driven water pump that will work to replace mine.

08-17-2016, 06:39 PM
The very best transom pickup is this Stainless Marine product:


Also, this Johnson crank driven pump is hard to beat:


And then, here's a link to a thread about installing a pickup in an 18 I worked on.


08-18-2016, 08:12 AM
something doesn't seem right

if you are sucking air thru bad seals the water temp would rise and continue to rise over a 20 minute run have you run it without the tstat? are the risers painted if they are do they have scorching on the paint? the risers usually have 4 water passages which exit bottom both sides and top all are important but the top one is key

08-18-2016, 08:17 AM
here is a possible pump replacement


sorry GC posted it too

08-18-2016, 12:40 PM
I had a similar problem years ago. Mine was blockage due to rusting in the water passages in the old risers and manifolds. If you were getting air from the drive pickup, wouldn't the engine be overheating too.

Just Say N20
08-18-2016, 02:10 PM
Thanks George, that is the water pick up I used on the 16.

I simply could not find a link to it anywhere.