1989 3.7 Litre 165HP Fresh Water System Overheating

Faubertlx

Cadet
Joined
Jul 26, 2011
Messages
8
Ok,Here we go.

When I originally got this boat it did not move for 3 years, I went through all the checks, the first time we took it out it had the original coolant mix/ratio in the tank.

Then a few uses later It overheated, not a big deal, the coolant was never replaced, so I put all anti-freeze (not reading the manual and assuming) we took it out on the lake and within 5 minutes the pressure risen enough to allow the pressure release cap to open blowing anti-freeze back all over the motor, and then at the same time its backing into the overflow tank which was dumping everywhere.

The same day before we went out we started it in the drive way and ran fine at idle for about an hour. However i noticed the water flow was not that great coming out of the exhaust, I believe i need to replace the impeller, however here is what im wondering

1. IF the pump WAS working PROPERLY, With 100% anti-freeze running at full throttle would that cause over heating? (or that scenario)
2. What is the proper ratio for the water/coolant mix?
3.Do i mix it in the tank? or in a bucket?
4.Where do I fill to?

Also, My exhaust bellow is done, Alpha One, I have two 89' 192 classic well crafts, one HAD the bellow that went from the gimbal to bell housings, my parts boat i believe has the new bravo bellow, where it connects to the gimbal housing but just butts up to the sterndrive when it trimmed down, since that is a new part, can I still use it or should i get the bellow that has clamps on both ends?
 

Failproof

Petty Officer 1st Class
Joined
Sep 26, 2011
Messages
273
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

100 percent coolant will not transfer heat well enough to cool. It would have overheated eventually. Mix i use is enough to protect to the coldest the mix will ever be exposed to. Never exeeding the percentage listed on the container. Too much antifreeze inhibits heat transfer. I like to premix. Then you know you did it right. Proper fill level depends on exact cooling setup. Revert to online manuals.
 

Faubertlx

Cadet
Joined
Jul 26, 2011
Messages
8
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

I have the Seloc manual, Thats vague, but my mercruiser technician said 50/50,

Also, Even if the stern drive pump was flowing enough water, think with all anti-freeze it would still overheat even with the proper amount of water flowing via the motor?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

I have the Seloc manual, Thats vague,

Congratulations... You have earned the 'Understatement of the year' award!!!

Faubertlx said:
but my mercruiser technician said 50/50,

The Merc manual for your engine (which I haven't uploaded yet so can't give you a link) recommends a 50-50 mixture of water and ethylene glycol. But read the container the anti-freeze came in.. The correct mixture ratio should be written on it somewhere.

Faubertlx said:
Also, Even if the stern drive pump was flowing enough water, think with all anti-freeze it would still overheat even with the proper amount of water flowing via the motor?

Yes.... 100% anti-freeze will not transfer heat quick enough.... PUT THE RIGHT STUFF IN!!!
 

Faubertlx

Cadet
Joined
Jul 26, 2011
Messages
8
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Thanks achris, I looked over the page, I take my statement back, the manual is great, There have been some tough things that poor book has walked me through, anyways, I changed my fluids and Im no longer overheating, but I did damage the rubber exhaust boot coming out of the coolant tank (if i had the book in front of me I could give you the proper component term) So I replaced that.

I have water coming out of the exhaust like it should when it is hooked up to the hose but i guess i can't tell if the impeller in the stern drive is shot until i get it in water, or a pull the out drive and replace the impeller no matter what.
 

Faubertlx

Cadet
Joined
Jul 26, 2011
Messages
8
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Thanks! Ill replace the shutter now since i pulled my transom for access to that area, it will be easier.

I have never replaced the impeller before but I have watched a few videos, I understand the manuals directions and im mechanically inclined, How long do you think that will take?
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,830
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Thanks! Ill replace the shutter now since i pulled my transom for access to that area, it will be easier.

I have never replaced the impeller before but I have watched a few videos, I understand the manuals directions and im mechanically inclined, How long do you think that will take?

It will take twice as long this time as it will next time LOL. Assuming it has not been off lately. 1/2 hour to drain od, 1/2 hour to remove, 1/2 hour to split and remove pump, 1 hr to reassemble, and 1 hour to service u joints and gimbal bearing check alignment (need tool, e-bay if you do not have one) and reinstall outdrive. That's two guys, and no beer till afterwords LOL. P.S. don't loose that lower shift shaft washer! Have fun.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,820
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

P.S. don't loose that lower shift shaft washer! Have fun.

Heh heh. I did that last time, couldn't figure out why it wouldn't shift. Put a hose clamp on as a "temporary" repair. This will be the second season with it, I'll fix it when I do the impeller next year...
 

Old Yeller Boater

Petty Officer 2nd Class
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May 17, 2010
Messages
191
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Yes, replace the impeller, and since it overheated I would replace the pump housing too. If your engine exhaust bellows was burnt, then your shutter is probably shot too. See here: http://www.mercruiserparts.com/Show...473.png&inbr=908&bnbr=230&bdesc=EXHAUST+ELBOW

Terry, could you tell me more about the shutter and what indications there might be of problems with it? The boat I have had the bellows split open last fall and was replaced, but nothing else related was checked or replaced. If I remove the shutter, is there something that could be seen to indicate replacement is needed?

Thanks!
 

stonyloam

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Joined
Mar 13, 2009
Messages
5,830
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

The shutter keeps water from coming into the exhaust manifold through the exhaust. For example you are moving along and shut off the engine, the boat stops and the stern wave hits the transom. The wave hitting could cause water to flow up the exhaust pipe into the manifold, and into the engine through a open exhaust valve. The shutter is positioned so that it blocks the incoming water. The shutter is located at the top of the exhaust pipe in most engines, you can remove the engine exhaust bellows (inside the boat) and see if it is there and in good condition.
 

Old Yeller Boater

Petty Officer 2nd Class
Joined
May 17, 2010
Messages
191
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Mine did not have a shutter, and looking at the exhaust pipe, there is no notches or anything that indicated something should have been there. is that a problem?
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 1989 3.7 Litre 165HP Fresh Water System Overheating

Mine did not have a shutter, and looking at the exhaust pipe, there is no notches or anything that indicated something should have been there. is that a problem?

You should really be starting your own thread OYB, this thread belongs to Faubertlx

You might also want to post your engine serial number and year, all the 470 style motors are not the same.
 
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