Help with aq125b. 87 bayliner capri

Hello I am new to boats and need a little guidance. I have recently picked up an 87 bayliner capri with the aq125b. It has a couple issues that i know of and could use some help. First is that the carb was just rebuilt but it will not start and run on it's own without feeding gas manually into carb. I noticed that it is not pumping gas from the bowl but it is full. The 2nd issue is that it drips from an expansion plug on the underside of the exhaust manifold when I have it running. The plug is not a concern and should be an easy fix. My concern is that it drips antifreeze and was wondering if it should have antifreeze in there as I thought only freshwater passed through it and out the back. If it is not suppose to have antifreeze in it, what could cause it? Any help would be greatly appreciated.

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Josh5806 said:

........... First is that the carb was just rebuilt but it will not start and run on it's own without feeding gas manually into carb. I noticed that it is not pumping gas from the bowl but it is full.
Check and see if the fuel pump is working properly.
If so, and if the pressure is within the correct range, check to make sure that the carburetor's needle/seat is not stuck closed.

The 2nd issue is that it drips from an expansion plug on the underside of the exhaust manifold when I have it running. The plug is not a concern and should be an easy fix. My concern is that it drips antifreeze and was wondering if it should have antifreeze in there as I thought only freshwater passed through it and out the back. If it is not suppose to have antifreeze in it, what could cause it? Any help would be greatly appreciated.

On these little OHC 4 bangers, only the engine will see Ethylene Glycol from the Closed Cooling System.
The exhaust manifold should see seawater ONLY.

Is it possible that the previous owner winterized this engine by pumping AF through the cooling system the last time it was laid up?

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The previous owner had said all he done to winterize it was pour through the fresh water system until it came out the outdrive. I was sure that it was not suppose to have antifreeze in the exhaust manifold but now I'm tasked with trying to find where the coolant is mixing at and allowing it to pass into there.

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Josh5806 said:

The previous owner had said all he done to winterize it was pour AF through the fresh water system until it came out the out drive.
That is a very risky idea. The AF can become diluted, and if not fully drained afterwards, can pose an issue during freezing weather.

I was sure that it was not suppose to have antifreeze in the exhaust manifold but now I'm tasked with trying to find where the coolant is mixing at and allowing it to pass into there.

There will be two caps on the system.
One pressure cap on the HE, and one cap over the seawater strainer.
If the PO poured AF into the seawater strainer and then put the cap back on, and then ran the engine on the garden hose/muffs, it would enter the exhaust manifold upon start up.
What you may be seeing could be a result of residual AFT in the manifold, and a bad welch plug (aka casting core plug) that is leaking.

Are you losing coolant from the heat exchanger?
Do you have a coolant recovery system?

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The PO stated he never ran the motor during winterizing. Only poured "pink" AF through strainer until it came out the drive. The drops from exhaust manifold plug is green so I dont believe it is residual. I have also noticed that the level of AF has dropped in the HE. As for a recovery system, it does not have one.

I have bought a seal kit and exhaust manifold gaskets but not sure what potential points could cause the escape of AF into the exhaust as I am in unfamiliar territory with this cooling system. As I understand, sea water comes in through the drive and to the HE and back out through the exhaust. The AF and water potential mix point would be in the HE if I am thinking correctly. Obviously I am guessing as this is new to me but what are the potential points that would allow AF to mix with raw water? I have thought about pressure testing but at this point it seems redundant as I know there is an escape between the two fluids. If needed for data i can pressure test but also are there any other "tricks" that could point me where to start? If there are in fact multiple points where it could be mixing?

heat exchanger failure or if the exaust manifold is AF cooled then the elbow gasket or exaust manifold

With the OHC 4s, only the engine is closed system cooled.
The exhaust manifolds are 1 pc and are seawater cooled.






The heat exchanger can be disassembled for maintenance and/or repair.

This is the AQ120B heat exchanger.




This is the AQ125B heat exchanger

So my best path is to start at the HE? I will start on removing that and have it inspected and/or repaired.

So I have removed the HE and expansion tank and found a pin hole in the HE. The insert where the raw water is suppose to flow was full of antifreeze which was going out the exhaust. The HE is at the shop for a good cleaning, repair and test. (Hope that was the only spot that was leaking.) While I have all of that out of the way I noticed the belt was worn and going to replace that and thermostat while I am in there to save labor later. My question is, would auto parts from a 92 volvo 240 with the 2.3 engine be the same and work? (Timing belt, tensioner, thermostat, etc?) I am also going to remove the exhaust manifold and replace the leaking plug and will just replace them all while I am at it. Do you know the plug size by chance?