Enduro 8hp water pump problem

[labougie]

I have a 1993 E8D Enduro (mostly the same as the earlier 8B) with an overheating problem - from cold there's a flow at the telltale but as it warms up,the flow diminishes until it's just steam. The block and head are too hot to touch at this point. I've been through the usual routes - water pump kit replacement, flushing the system with weak acid - I've even had the head off to check the gasket, then the powerhead off to poke wires through the waterways. I thought I'd found the problem - an external water hose at the bottom of the block had a blockage at one end, but on clearing this and putting it all back together, the overheating problem was the same, if not worse.

I've just discovered that if I take the lower leg off and attach mains water to the leg inlet pipe, the engine will run perfectly - no overheating no matter how hard I run it - what on earth can be wrong with a water pump which has had a new kit installed? I notice that if I submerge the leg and use an electric drill to turn the shaft, there's not a terribly impressive amount of water coming out of the rubber seal to the leg inlet pipe and also that there's an equivalent amount of water coming out the the top of the housing around the shaft. The impellor I'm using is the correct part - the same part number in both E8D and 8B parts diagrams. The parts diagrams show no kind of seal between the shaft and the housing - can anyone think why this is happening?

Thanks in advance.

[99yam40]

might try replacing the pump housing, kit should have cup and wear plate, but not the housing itself

[TownsendsFJR1300]

Is the new impeller installed in the SAME direction as the old one, ie, the arms, bent in the same direction?

They will NOT correct themselves.

Good luck and please post back what you find...

[labougie]

Driveshaft rotates clockwise viewed from above - impellor blades are bending anti-clockwise. I thought about replacing the housing but I've thrown a lot of money at this motor and it seems like I could easily be throwing good after bad. What could be the problem with the current housing?

[TownsendsFJR1300]

Tks for the update..

Sounds like the impellor is correct.

If there are any imperfections in the SS housing, base plate, etc, WILL hamper the WP. Should an o-ring be slightly out of place, same thing.

IMO, I would probably drop the unit again, compare with either the shop manual or the parts fisch (located in RED above^^) that you have all the correct parts, correctly seated, the housing the SS cup rides in, is NOT damaged, warped, etc.

Not sure if this is the same LU as yours;

http://www.boats.net/parts/search/Ya...201/parts.html

[labougie]

I heartily wish that one were mine! It seems to have an O ring and also a water seal around the driveshaft exactly where mine's leaking! Mine is here:

8B Mariner Outboard 677-300101 AND UP GEARHOUSING ASSEMBLY Diagram and Parts

I have already replaced part #13, the bearing housing below the impellor, which was corroded and I thought might be impeding water flow, but no difference. Cup and wear plate seem undamaged - this is a serious mystery!

[TownsendsFJR1300]

I'm guesstamating now but can you check most to all water passages in the LU just to make sure no mud dabbers, corrosion, etc hasn't clogged a passage?

Someone else is going to have to chime in as I don't have any other idea's..

Good luck with it and lease post if you find the issue..

[labougie]

I'm afraid I've given up on it and bought myself another motor. One can only bang one's head against a brick wall for so long! Thanks for all the input.