84' VP 125A cooling issues?

[JoChek219]

helping my neighbor on his boat... replaced impeller at the front of the motor and a new thermostat.... having problem with not getting water through the cooling system ( closed Cooling) took hose of the inlet pipe ran water from a garden hose from pipe to drive and water was coming out so no clogs there... and then took off impeller and put hose on other direction ..water flowing that way so no blockage? any ideas or if anyone had any schematics of the cooling system or anything that would be greatly appreciated

 

[JAL51974]

Re: 84' VP 125A cooling issues?

Is this a closed cooling system or raw water cooled? My 125A has the raw water cooling down the antifreeze via a heat exchanger. The antifreeze is stored on the right side of the engine with the heat exchanger on the left side as you look at it while in the boat. there are lots of things to check out if it is raw water cooled. Give us some more information and we can help you diagnose it!

 

[Mischief Managed]

Re: 84' VP 125A cooling issues?

99% sure all 125As were FWC, due to the aluminum cylinder head.

It's probably the connection of the water inlet hose on the lower gearcase. It will fail, it will allow air to be sucked in by the raw water pump and the engine can't cool down. Very common problem. Hook up your "ear muffs", crank up the the water flow, keep the engine off, and plug up the bottom water inlet hole. You should find the leak because water will be coming out of it.

 

[JAL51974]

Re: 84' VP 125A cooling issues?

I thought they were FWC too.

Check this forum for a search on this topic, it has been up quite a few times over the past year with good suggestions on diagnosis.

i couldn't find mine by the suggestion used by MM. The leak was at the water neck fitting, a common culprit as they get corroded on the inside even though it looks OK on the outside, letting air in hence overheating. On these engine drive combos overheating = air sucking in instead of water.

Be patient, you will find the air leak.

 

[JoChek219]

Re: 84' VP 125A cooling issues?

ok thanks for the suggestions! Keep 'em coming. Will go over to my neighbors and see if we can't figure this out.... I'll keep you posted on our results

 

[JoChek219]

Re: 84' VP 125A cooling issues?

how much pressure/suction should there be on the intake on the sea water part of the cooling side? And also is there an impeller in the drive?

 

[JAL51974]

Re: 84' VP 125A cooling issues?

sorry it took so long to reply I haven't looked at this thread lately!
Enough suction like from a shopvac, that is what I used anyway. You have to figure out how to rig it so that you reduce the size of the vac hose down to the piping then tape it or something like that. I used the attachment that reduces the shop vac down to vacuum small things like the keyboard on the computer...it works. The only impeller on that system is on the engine which you already changed out. Make sure there is a good seal on both front and back of that pump. There is a rubber washer on the rear side which goes bad therefore leaking air too sometimes.

 

[JoChek219]

Re: 84' VP 125A cooling issues?

neighbor replaced the housing too where the impeller goes.... says its still running warm..... but I'll tell him to make sure about that washer and seal on the back of the housing....thanks for the advice