raw water pump

[hinters]

Good day all.
I have a Moyer exchange engine with about 50 hours on it and I have a lot of steam coming out of the exhaust. It is fresh water cooled and runs at 190 degrees at 1700 RPM. If I try to run it faster the temp starts to climb.
I had the heat exchanger hot tanked at a rad shop when I put the new engine in.
I thought perhaps I am not getting enough water flow from the raw water pump so I took the outlet hose from the pump and led it into a bucket
and started the engine for a few seconds to check the flow.
I get only what I would call a strong trickle from the pump with the engine
running, almost the same as with the through hull open but the engine off, not a strong flow as I would expect.
OK so, open up the pump..all the vanes ar present and accounted for. Put in
a new impeller anyway but no change to the flow rate.
Question..how much flow should I be gett from the raw water pump?
I should also mention I have checked all the hoses, Exhaust manifold, Riser etc and can find no blockages.
Anybody got any ideas? I have run out of things to check.
Thanks for any ideas you can share.
Pat
Lions Den
1972 Ericson 35-II

[Marian Claire]

Have you checked the flow from the pump upstream to the thru-hull? Disconnect the line feeding the pump and open the thru-hull. You should have a good solid flow if the end of the hose is below the thru-hull. If not work your way back to the thru-hull. Do you have a raw water filter or a T valve up stream of the pump? My two low flow incidences turned out to be stuff blocking the thru-hull and the T valve both of which are up stream of my raw water filter. Dan S/V Marian Claire

[hinters]

Raw Water Pump

Thanks Claire
Yes I removed the hose from the through hull and the flow there is fine.
I have a strainer upstream of there which is also clean. Next is the line to the pump and the pump itself. I can disconnect the line into the pump and blow back through the through hull with no problem so I believe that line is clear. The next thing in line is the pump itself where I believe the problem to be. I get very little flow coming out of the pump even with the engine running.
I havn't measured the flow in GPM 'cause I don't want to run the engine too
long with no flow. I would extimate about 1 to 1.5 GPM with the engine on.
That seems very low to me. The through hull is only 1/2 inch and maybe that is too small for the pump to generate enough flow, although that hasn't changed since whenever, so I don't know why that would be the problem.
When I am cruising under power the water comming out the transom is almost too hot to hold your hand there for more than a few seconds so something is definately not right.
I guess I will start relpacing things one by one from the through hull on until
I find a solution.
Wish me luck.
Cheers
Pat
Lions Den
Ericson 35-II

[ndutton]

Before you start replacing things, suggest you thoroughly read this thread:

http://www.moyermarine.com/forums/showthread.php?t=4222&page=2

especially post #14. You might have a similar issue.

[hinters]

Raw Water Pump

By jove...I think I've got it!
Took the inlet hose off the pump where it had the mandated
two stainless clamps below the water line. Turns out the second one
was clamping the hose closed because the barb was too short to accomodate
two clamps.
Cut off the crimped section...reconnected with one clamp and started 'er up.
WOW..water flow out the transom increased 3 to 4 fold! Took the outlet
hose off the pump and led it into my 2.5 gal bucket. Filled it in less than 30 seconds.
Thanks to all those who read this post and those who responded. Now I just have to punish the culprit who followed the recommendation of the surveyor
and doubled up those clamps. (Guess who)
Cheers
Pat
ps I will try and post a picture of the offending hose end. It was restricted from 5/8 to about 1/4 inch. The clamp was good and tight though.

[tinkerer]

raw water pump

I don't think this my issue with my A4 and Oberdorfer pump. Thru-hull water flowed nicely to the primary screen, but somehow did not continue thru the pump/impeller section. I replaced the impeller, unlike the SERVICE and MAINTENANCE INSTRUCTIONS for the MMI FLEXIBLE IMPELLER PUMP. when i pulled on the impeller as instructed, the whole shaft came out with it. I did this all after disassembling the pump from screen to T-valve, so I had some pipe come with it.
Newly installed, no water flow but I can see the shaft is turning and the impeller blades are bent the correct way. Any help?

[Marian Claire]

You mention good flow at the thru hull. Do you have good flow out the hose that feeds the pump? If so then you could have the famous none squished impellor problem. Dan S/V Marian Claire

[tinkerer]

raw water pump

Thanks Marian
what is the none squished problem?? I'm keen to hear this one.

[Marian Claire]

I believe Baltimore Sailor was the first to notice this. When placing a new impeller in an old water pump, either due to wear or slightly smaller thickness of the impeller, the fins did not make good contact with the walls of the pump. Therefore no or low water flow. I must say I have been away from the forum for a few weeks and may have missed some posts on this issue. Others may have more up to date info. ndutton refers to this in post # 4. Dan S/V Marian Claire

[ndutton]

Actually, the seal is lost between the impeller vanes and the face of the pump due to pump depth, short impeller or a combination of both (to encompass all theories).

[Marian Claire]

Right. I should have said edges of the fins. Thanks. Dan S/V Marian Claire

[tinkerer]

raw water pump

Thanks to both of you for your efforts. Well, pump seems to be pulling water through with the help of the new impeller and there is raw water reaching the T junction. However, the manifold seems to be heating up and so I think something is clogged there. A pressure flush needed? Don't know if I can do so myself. Do I need to get professional help now?

[ArtJ]

You can easily do it yourself. I suggest a couple of things

First , purchase Don Moyer's flushing kit. It is a great aid and comes with
all the fittings necessary. I think around $60 bucks.

Second get a copy of his Video on the cooling system which goes thru
all aspects of the cooling system, including flushing and rebuilding pumps

Regards
Art

[tinkerer]

raw water pump

Thanks, ArtJ
I'll do that because I detached the hose coming out of the manifold going to the exhaust and no flow there. There is flow from the pump to the T-valve and it seems through the thermostat as well. So the problem must be within the manifold or somewhere in between, I guess.

[JOHN COOKSON]

Easy Stuff First

If there are any 90 degree fittings or elbows at either end of the manifold check them for blockage and clean out if necessary. A lot of the time this is where blockage occurs.

Maybe you'll luck out and solve the flow problem this way.

TRUE GRIT