1986 Bayliner Capri AQ131/275 Over heating

dennis461

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Aug 11, 2011
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Does you engine run fine in a bucket like my picture shows?
You said," ..on lift submerged..."
In my pic, the elbow is ABOVE the water.
If the hose has a hole in it, or the elbow was rotted, it would suck air, and overheat.

When you wrote ," ..on lift submerged..." did you mean the ELBOW is submerged?
 

stratostan

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Apr 4, 2016
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Yes. When it was on my lift and the elbow was submerged it cooled fine. I am still waiting on my part. I think this will be my solution
 

stratostan

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Apr 4, 2016
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Got it replaced. Had a storm last night, so I was not able to get the boat in the water. I am going to test it hopefully tonight, to see if this is the cure!
 

stratostan

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I spoke too soon. It is still over heating. I actually removed the thermostat and it still runs hot. I checked the impeller for damage, it was replaced earlier in the summer and still looks new. Any other thoughts on what the issue could be?
 

dennis461

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pull cover off of the raw water pump
Lay straight edge on the inside.
Is it worn down like in my picture?
 

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stratostan

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If it is worn down where there are gaps like your picture, does that mean it just needs to be replaced? Low suction? Restricted water flow?
 

dennis461

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If it is worn down where there are gaps like your picture, does that mean it just needs to be replaced? Low suction? Restricted water flow?


The system needs to be airtight from leg to raw water pump,
That's AIRTIGHT.
On mine, I had to take the copper tubes off the boat.
Made the ends (where the rubber d-ring seats) perfectly flat.
Re bent ever so slightly to make sure they seated properly in the pump.
They cannot 'tilt' otherwise the rubber d-ring will not seal.

The picture is my bad pump which allowed water to flow around the impeller, thus preventing sufficient suction on plane.
The cover gasket must be VERY thin. I made one once out of gasket material and the pump was worse.

If the cover is worn, than most likely the other end is worn and you may need a new pump.
You already replaced the neck. If it is not completely sealed, Your system will not work.

Bring the boat to New Jersey and I'll fix it for you.

Start taking a bunch of pictures for us to analyze.
 

stratostan

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Apr 4, 2016
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Thanks for the advice! I will disassemble tonight and try to take some pictures. How about gasket maker material? Would it be better to use the silicone type gasket maker material when sealing the water pump?
 

stratostan

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Here are pictures. Would this gasket material be ok to use? I noticed a slight drop of water by the copper lines coming from the water pump. Would that be enough to cause an issue?
 
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jerryjerry05

Supreme Mariner
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May 7, 2008
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Any scoring on the pump cover? Closeup pics??
​How about back inside the pump at the rear?
Remove the pump.
Reassemble it.
Try blowing through the pump as you turn the impeller.

If you can blow through the pump as you turn it?
You probably need a new pump.

Another test, put it back together.
Start it on a hose or in the water(best) then disconnect the outlet and rev the motor.
If it doesn't push a LOT of water as it revs up then the pumps probably bad.

One more pump thing.
The cam inside the pump it's over the inlet and squeezes the impeller to make suction.
The cam can wear down and not work good at high speeds.

Or like I suggested in my other post: the exhaust manifold or the heat exchanger.
How old are they?
Do a visual inspection on the end of the manifold.
ANY clogged outlets?
 

dennis461

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Here are pictures. Would this gasket material be ok to use? I noticed a slight drop of water by the copper lines coming from the water pump. Would that be enough to cause an issue?

The picture is not large enough for me to view for any gap.
I would only use the OE gasket for this, it should come with the impeller and be very thin.

As for drops of water, find the source..if the shaft seal is worn, or the leak is from the bottom tube, it could be a problem.
 

stratostan

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Apr 4, 2016
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I put it back together. I am wondering how to check the exhaust manifold for plugged up ports? I am thinking it could be there or a leaky headgasket. How do the head gasket sealing fluids work?
 

dennis461

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Aug 11, 2011
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I put it back together. I am wondering how to check the exhaust manifold for plugged up ports? I am thinking it could be there or a leaky headgasket. How do the head gasket sealing fluids work?

Exh manifold;; get boat out of water and use large plastic tub or 50 gallon drum to run engine.
See how much water comes out of the exhaust.

If you cannot draw water up from tub, open the drain under exhaust manifold, near the stern, it should be right next to where the copper tube connects.
If leaving this drain open allows you to draw water up from the tub. You might be close to fixing this boat.

Option 2; remove heat exchanger. Force water in where the copper tube connects. Make sure no water comes out the ports which receive gases from the head.
Meaning all water should come out the round part which connect to rubber connector to outdrive.

I doubt your head gasket is a problem if the boat can idle a long time with no problems while sitting in water/lake.
 

jerryjerry05

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The "sealing compounds" Anything you add to the fresh water side(heat exchanger) will only clog that side up.
​It's not like a car with a big radiator where the stuff can settle to the bottom after it seals any leaks.

To test the manifold? Loosen it and remove the rubber boot between the manifold and the down tube.
Get a mirror and a good flash light.
Try to look back up into the end of the manifold.
 

stratostan

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I had found a head gasket sealer at Menards. It is one that is mixed with the antifreeze/coolant. I did not know if it would be worth buying to help with my issue.
 

Fishermark

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I had found a head gasket sealer at Menards. It is one that is mixed with the antifreeze/coolant. I did not know if it would be worth buying to help with my issue.


It will not help, and will only make matters worse (at best).
 
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