Aq131a overheating

[Stearns250]

Ok so I have replaced the elbow and gasket rubber seal for the elbow and used gasket maker to seal it up and I am still overheating. Did I install the seal wrong I made sure the sealing ring was face down and used the silicone on the sealing ring. Worked great my first trip out and now back to overheating.

 

[Scott Danforth]

do you have flow from the raw water pump? when was the last impeller change?

 

[jerryjerry05]

Does it overheat at idle? or when on plane?

Silicone around the base of the elbow.

The AQ131a was from the 80's so it OLD!!
Other possible problems, manifold clogged? They can look new and still be bad
Was doing a used boat inspection and it was a AQ131 and the manifold looked new, I reached to the back and touched the top and poked a hole through it.

The pump: the front wear plate, cuts and grooves, the housing scored, the cam worn down.
But mostly the manifold.

 

[Stearns250]

So it overheats anytime I go above idle. Sitting idle it will cool right back down. Basically I can go up and down the lake very slowly. I did have the problem fixed one time and that was when I changed that seal but I think using silicone to install it might be the problem and thought I would ask here. I checked the manifold and it seems good.
​​​​​​The impeller and raw water pump gets rebuilt every year.

 

[Stearns250]

The silicone was put around the bead. The side that connects to the fork and the pickup tube.

 

[dennis461]

So, this is the boat that was leaking water from the pump?
Is it still leaking.

"​​​​​​The impeller and raw water pump gets rebuilt every year."
You cannot rebuild worn out brass.

Check the raw water pump front plate for wear.
This pump would not draw water high enough to work when boat was moving.
If front plate is worn, then the pump itself is also worn and may need replacing.
Also, the front cover gasket must be very thin, do not make one out of thicker gasket material.

Rubber grommets on copper tubing must be correct part and installed correctly.
The pipes need to sit SQUARE in the pump housing.

Can you check for flow by opening the plug/petcock in the starboard side copper tube and the manifold bottom?

 

[Stearns250]

Yes it's the same boat. I have fixed all the leaks with new seals all around. Also had to tighten the motor to the transom and that stoped the boat from taking on water.
i will check the pump cover when I get home in the a.m.
On muffs she will pull water but it's intermittent.

 

[jerryjerry05]

That sounds like the elbow isn't sealing right.
Or the water tube in the drive isn't sealing and sucking air as you get up on plane.
It has 2 o-rings that seal the tube.
Or the hose isn't connected to the transom.

 

[Stearns250]

Well here is where I am now. I took off the heat exchanger took it apart and cleaned the insert. Put it all back together with new seals. Ran water through exhaust manifold and flow was good. Found that the strainer was missing an oring so I replaced that and installed a new seal on the elbow for the outdrive. I also replaced the raw water pump.

 

[jerryjerry05]

That insert can be acid dipped.
Just not too long.
Maybe a radiator shop?
New it's REALLY expensive.

I've found if it's clogged not much can be done other than back flushing and taking to
a radiator shop..

Try taping the muffs on the drive and try to seal it as good as possible.
Then watch the drive as you turn the water on.
Should be no water out the drive anywhere.

 

[dennis461]

That insert can be acid dipped.
Just not too long.
Maybe a radiator shop?
New it's REALLY expensive.

I've found if it's clogged not much can be done other than back flushing and taking to
a radiator shop..

Try taping the muffs on the drive and try to seal it as good as possible.
Then watch the drive as you turn the water on.
Should be no water out the drive anywhere.

Another easy (IMHO) way to test for leaks is;
1. duct tape drive water inlet gills shut.
2. put cork in bottom 1/2 hole under leg
3. disconnect inboard 3/4 hose from copper tube
4. connect longer (4') hose to existing hose and raise above transom.
5.fill hose with water and look for leaks