cooling questions

[gerg1962]

Hello,
Brand new to the group.
I obtained (for free!) a 1971 Reinell 24' boat last week and it has an OMC outdrive with what I think is a GMC 307 V-8.

It appears that is has a closed cooling system and I do not quite understand how it works.

I want to see if I can get the engine running and I borrowed a copy of a Seloc manual from the library. There are all sorts of warnings about not running the engine unless water is circulating. From all the diagrams I see in the manual it looks like the water pick up is above the prop.

How do I get water in there so I can run the engine?

I had a boat before with a Mercruiser outdrive and I had some flaps to force water in. Doesn't look like it will work here.

I also noticed a flushing fitting on the side of the outdrive and the manual refers to this but I am not certain if I can just hook up a hose and run the water through this to run the engine.

Maybe someone can educate me?

I gather the water keeps the coolant in the engine cool by virtue of this cylinder mounted at the front of the engine - a heat exchanger?

Thanks in advance for the help!

Craig

 

[bruceb58]

Re: cooling questions

If the hose fitting you have is at the pivot cap, you can run your engine with water going in there. This is what it looks like:

 

[southkogs]

Re: cooling questions

Welcome Aboard Craig!

On my I6 the thermostat housing is at the very front of the engine on the top. But I wouldn't call it a cylinder. I'm wondering if you're perhaps confusing part of the trim system for cooling stuff.

A '71 Stringer shouldn't have a closed cooling system that I can tell from anything that I have. So, I'm thinking you have a sea/fresh water system like mine. In which case, before you run it on out of water - hook your garden hose up to the fitting that Bruce posted a photo of.

 

[gerg1962]

Re: cooling questions

The fitting I have looks just like that only it is on the other side of the outdrive, I am hoping the function is the same!?

There is (green) coolant under a radiator cap so that is why I thought it is a closed system.

I will get a picture of it tomorrow and post it.

It is a cylinder about the diameter of a propane tank one would use on a propane torch but is about 2.5 times as long.

I thought it may have been some sort of heat exchanger.

Obviously I am not that knowledgeable about boats.

Thanks for the help so far!

 

[Howard Sterndrive]

Re: cooling questions

here's some good diagrams on closed cooling:
http://www.perfprotech.com/store/articles/fresh-water-cooling.aspx

The fitting I have looks just like that only it is on the other side of the outdrive, I am hoping the function is the same!?

same yep

 

[southkogs]

Re: cooling questions

Obviously I am not that knowledgeable about boats.

Apparently, that makes two of us

Didn't know they had that. Pretty cool.

 

[gerg1962]

Re: cooling questions

Well glad we got that sorted. Now I have bigger problems to tackle, like the engine is stuck!

I Put a breaker bar and socket on the crank pully bolt to cycle it through a few times before I tried the starter. I am only getting about 1/4" of movement either way which is probably just slop in wrist pins and crank.

I pulled the plugs and squirted some Gibbs penetrant in all the cylinders and rocked it back and forth a few times to get the stuff moving around in there.

Anyone else have any other tricks to unstick a stuck engine short of pulling it out and doing a rebuild?

If I can't get it to run it is time for it to go away before I sink any serious money in it.

Craig

 

[Bondo]

Re: cooling questions

Anyone else have any other tricks to unstick a stuck engine short of pulling it out and doing a rebuild?

Ayuh,... Pull the drive, so ya know whether it's the motor that's stuck, 'n not the drive...