1985 Mercruiser I/O,140 hp, 4cyl - Engine Diagram, How to Winterize

[MVAPTON]

Hi,

I have to winterize my boat as the new owner for the first time. Could you provide me with some assistance? I've worked on a few things myself this year, but I need a diagram of the engine. I've released one petcock but am not sure if there are any more. What else do I do to winterize?

Blondie, the new boat owner

 

[SteveRay]

Re: 1985 Mercruiser I/O,140 hp, 4cyl - Engine Diagram, How to Winterize

Should be two...both port side.
One is on the lower part of the block and one directly above on the manifold.
Check if there is a power steering cooler also.

Might want to remove the large hose on the thermostat housing to check for water also. As guys on here taught me, poke around with a piece of wire or something in the drains to lossen up any dirt or sediment that could block the drain holes

 

[Bondo]

Re: 1985 Mercruiser I/O,140 hp, 4cyl - Engine Diagram, How to Winterize

What else do I do to winterize?

Ayuh,.............
Welcome Aboard to the forums here at iboats.com,........

To answer your Question,.........
It's All in Here..............

 

[buck74]

1984 Mercruiser I/O,120 hp, 4cyl - Engine Diagram, How to Winterize

1984 Mercruiser I/O,120 hp, 4cyl - Engine Diagram, How to Winterize

I also need help with winterizing my mercury. I think that I have a 1984 model I/O mercruiser. I know the engine is a 4 cylinder mercury, I think it is 120 HP, 2.5L.

I have two 7/16" brass plugs on the manifold, one low and one high. There also looks like a pepcock on the block just below the lower brass plug on the manifold. I took out the lower brass plug, and the water ran out of the exhaust manifold. I was told to put it back in, take out the top brass plug, then take the top hose off of the water pump, and fill with the pink antifreeze until it runs out the top plug hole. Then put the top plug back in. Is this correct?

What about the pepcock, I assume this also needs to be drained. Which way to I turn it (I assume to the left) to open it? How far am I suppose to turn it ? 1/4 turn perhaps. Are there any more of these on the block than the one under the exhaust manifold? If so where are they? Do I leave it open all winter, or close it after the water drains out?

What about the lower unit does it need to be drained? I have read the oil should be drained. If so where is the plug, and how is it refilled? How do I know how much? I am guessing this is 90 weight gear lube, of lower unit lube. Do i wait and refill it in the spring, or fill it now before winter?

Also (sorry) I was told to remove each spark plug and put in 4 ounces of marvel oil. Now I am reading about fogging the motor, but I already have it in my garage. Is the marvel oil treatment good enough? Should I remove the coil wire and turn the engine over a couple of times after putting the marvel oil in the cylinders?

Any other advice you can give me would be great.
Thank you. Frank

 

[Don S]

Re: 1984 Mercruiser I/O,120 hp, 4cyl - Engine Diagram, How to Winterize

Re: 1984 Mercruiser I/O,120 hp, 4cyl - Engine Diagram, How to Winterize

You need to start a new thread of your own, not open an old thread with your questions stuck at the end of it.