351w cooling problems

[mtduckhunter]

I am new to inboards, and i have a 1989 challenger with a 351 winser engine.

the problem is that it seems to overheat, the water intake is on the bottom of the boat (which im sure most are). there is a valve on the inside, and a bowl with a screen in it, and then the hose from the bowl continues to tha motor, i was thinking it was the water pump, or maybe the thermostat, but i dont know where the thermostat is. I put a water hose in the bowl and ran the engine at idle speed, there wasnt any water being sucked up to the engine.

so my questions are

Is there something simple im doing wrong? because i have no experience with
inboards.

where is the thermostat located at?

Could the water pump be clogged or bad?

 

[Don S]

Re: 351w cooling problems

First thought "Raw water pump impeller"
From there we go to needing to know engine marinizer. OMC, Volvo, Mercruiser, Marine Power, Crusader, Etc. Etc.
Without that information it's impossible to answer any of your questions accurately.
IF you don't know what it is. post some pictures, we can help from that alone.
Is this really an inboard, it's amazing how many people call their boats inboards only to find they have an outdrive and it's really an IO.

 

[Bondo]

Re: 351w cooling problems

and then the hose from the bowl continues to tha motor, i was thinking it was the water pump,

Ayuh,....

I'm bettin' that on the motor end of that hose is the Raw water pump,...
There's a rubber impeller in it that needs changing...

That's always the 1st place to look with an overheat condition.....

 

[mtduckhunter]

Re: 351w cooling problems

i will try to get some pics posted up, because i dont know the marinizer.

i pulled the impeller to inspect it, and it is a little chewed up, its compressed on the top when its in the housing, i suppose its supposed to be like that.

 

[Don S]

Re: 351w cooling problems

No, it should be perfectly round and all blades of the impeller intact and straight.
Replace it, it's a maintenance item that should be replaced every couple of years.

 

[Bondo]

Re: 351w cooling problems

i pulled the impeller to inspect it, and it is a little chewed up, its compressed on the top when its in the housing, i suppose its supposed to be like that.

Ayuh,...

As you could see, the impeller flexs from straight to curled blades to pump water,...
The impeller should have No imperfections,...
The Housing should also have No imperfections, or scratches, grooves, etc...
The Missing Pieces also have to be Found,+ Removed, or they'll be an Issue...

 

[mtduckhunter]

Re: 351w cooling problems

this is the drive, i dont know if you can tell the marinizer by this.

the front of the engine

this what i was talking about the impeller being compressed at the top by some piece of brass.

i reinstalled the impeller after removing the brass piece and this is what it looked like. fit nice and snug.

sorry a few of the pics arent very clear, i will post more if needed.

 

[Zackman]

Re: 351w cooling problems

this what i was talking about the impeller being compressed at the top by some piece of brass.

I believe that brass piece is the diffuser and is needed for a centrifugal pump to work properly (little hard to tell from the out of focus picture, or may be my eyes). I believe you need to reinstall that brass piece.
​

 

[a70eliminator]

Re: 351w cooling problems

impeller looks ok, it's supposed to look curled like that, thats where the wipers are doing their thing, but definately replace it since your in there anyhow but i would be looking elsewhere for the cure.

 

[mtduckhunter]

Re: 351w cooling problems

I started disconnecting all those hoses to make sure they arent stopped up (why they would be i dont know).

Could it possibly be that the thermostat is stuck? if so, where is it located at?

 

[Don S]

Re: 351w cooling problems

That brass piece is the cam, and it MUST be in there or you don't have a pump, you would then have a mixer.
If you knew what made those pumps work, you would understand.
I will try to explain. When the vanes start to open up as they come off the cam, they are over the intake port of the pump. As the vanes straighten out, the water is sucked into the larger cavity. That water is then moved on around the pump and the vanes start getting spueezed down again, which then gets pushed out of the pump and into the engine and manifolds.

This drawing might help to understand the process

One other problem I see with your impeller, is that it's too short. the shaft is sticking out past the impeller. The impeller MUST be tight between the cover and the base of the inside of the pump. IF not you have no seal and no pumping action.

Wrong impeller, and no cam. Not a snowballs chance of that pump pumping anything, let alone cooling your engine, not a chance.

 

[mtduckhunter]

Re: 351w cooling problems

Thanks Don i understand it a little,

i took the intake hose off the right side of the pump and turned over the engine and i could feel it sucking, took the hose left side and couldnt feel any air coming through.

its got to be something with the impeller, maybe it is the wrong impeller.

 

[Don S]

Re: 351w cooling problems

maybe it is the wrong impeller.

What do you mean maybe, it IS the wrong impeller

 

[Bondo]

Re: 351w cooling problems

Ayuh,...

Generally speaking,...
Most Stuff works alot Better when assembled with the Right Parts....
And,...
That's Most Definitely the Wrong impeller....

 

[CharlieB]

Re: 351w cooling problems

Even with the out of focus pictures it is clear to see that THISS is NOT the correct impeller for this pump.

The length is too short and does not fill the pump cavity to the cover surface.

Get a clear picture of the pump cover, that should identify the pump and one of us should be able to help you locate the correct impeller part #.

 

[mtduckhunter]

Re: 351w cooling problems

pics of the pump cover, i put whiteout in the letters to help you guys see it better.

 

[Don S]

Re: 351w cooling problems

http://www.sherwoodpumpsdistributio...mps/USMarine/P151_Detail/Related+Products.htm

 

[a70eliminator]

Re: 351w cooling problems

Guess that explains why the wrong impeller was put in there.

 

[Don S]

Re: 351w cooling problems

You can get the impeller kit here at iboats.
http://www.iboats.com/Boat_Parts_Ac...**********.331887185--submit.x.37--submit.y.9

 

[mtduckhunter]

Re: 351w cooling problems

thanks guys! i will get that ordered soon