MC1 questions

[Sangster21]

Hello, this is my first post.... my first boat too. I bought an older Sangster hardtop that needs quite a bit of work. I have already gutted it and pulled the leg and engine. Mercruiser 165 I6 with I believe the MC1 outdrive. It needs new floor and stringers and for sure a re wire. According to the old fella I bought it from, the engine and drive worked just fine. Wiring looks like 40 years worth of hacking on it... needs a re do. It has the hydraulic trim sender (don't think it works), can it be deleted? I don't think I particularly need a trim gauge, so can I remove the hydraulic unit completely? I have downloaded and started to study the wiring diagrams, but will have lots of questions for sure. The alternator when removed from the engine spins and sounds pretty growly, I think a new one is in order. I would guess that the marine version of the delco 1 wire alt would be an easy and affordable replacement. Lastly (for now), the engine uses a heat exchanger for cooling. When I pulled the engine out and had an inspection, I noticed coolant (ethyl glycol) in the exhaust manifold at the exhaust riser end. The manifold "looks" ok , but I can only assume that the water jacket must be holed and needs replacement. Maybe some joggling about in the engine removal did it in.
Thanks
Alan

 

[Sangster21]

Re: MC1 questions

Seems like a good time to try to figure out how to attach pictures.... I think it worked.
As I understand it, the manifold only sees the closed loop coolant not sea water, so if there is coolant leaking into the exhaust passage it must be a rotted out manifold. If it only sees coolant, why would it rot out? I did look carefully into the intake and exhaust ports, but did not see any sign of leakage there.
Alan

 

[kickinghorse]

Re: MC1 questions

Alan.
Welcome aboard! That's a nice looking boat you have. I've heard those old Sangsters are good solid boats. Keep us posted on your progress.

 

[achris]

Re: MC1 questions

That closed cooling system is NOT Merc genuine, so you will have to trace out the hose paths to find out if the manifold is actually inside the closed loop. The other possibility if it is in the loop is that it was put on well after the engine had been run in seawater raw water cooled. If that was the case then the corrosion would have already started and it's entirely possible it just kept going, even after the closed cooling was added.

Chris..

 

[Sangster21]

Re: MC1 questions

The fellow I bought the boat from claimed it ran a bit hot, and he did all sorts of service on the cooling system. The leg pump is new, the heat exchanger was cleaned out at a rad shop. Looked very clean when I pulled the end caps off to look inside. I wonder if cooling the exhaust manifold on the closed side is too much for the cooling system to handle? The manual shows raw water cooling the manifold not "fresh". What is the best plumbing path to follow when re installing the engine and cooling system?
Thanks,
Alan

 

[achris]

Re: MC1 questions

If he did all that and it still running hot, then the only things else that needs to be checked is the water pocket cover in the bottom of the top section ("drive shaft housing") of the 'leg'... If that's ever been hot then, being made of plastic, it distorts and the gasket leaks. Not water out, exhaust gases in... which reduces the amount of water available for cooling. The easiest test for it is to put a section of clear plastic hose in the water line from the back of the engine (where it comes in from the leg), run the engine normally (MUST be in the water as it needs back pressure on the exhaust gases to force the leak) and look for bubbles in the water stream. You would need to run 'normally', not just at idle...

HTH,

Chris.......