1981 Mercrusier 140 hp Leaking Water

[Brent M.]

I have a 1981 Mark Twain 16' V-Hull Ski boat, it has a 140 hp mercrusier. I have just got it running its been sitting for about three years, the engine starts fine and runs and sounds good. But the problem is that is has a bad water leak, if you are in the boat looking at the engine the water is leaking from the left side on the back of the engine just behind the starter. I have been running the engine on muffs in the driveway and the water is comming out with a good bit of pressure. I have read some posts concernig simmilar problems and seems that they were talking about the shift bellows and the drive and exaust bellows. Does this sound like the same problem or is it somethig else?

 

[maverick3656]

Re: 1981 Mercrusier 140 hp Leaking Water

it could only be the bellows if the boat is in the water. sounds like a freeze plug to me.

 

[Brent M.]

Re: 1981 Mercrusier 140 hp Leaking Water

Thanks Mavrick, but I cannot see a freeze plug where the water is comming from. Are there freeze plugs at the back of the engine that you cant get to untill you pull the engine? Also if its not to much trouble can you tell me how you knew that the problem with leaking bellows only shows up when the boat is actually in the water not on the muffs, I am knew to the whole inboard engine thng? Thanks

 

[Maclin]

Re: 1981 Mercrusier 140 hp Leaking Water

You said the water comes out the back of the engine while in the driveway on muffs and only with the engine running so it is not a drive bellows problem. With a leaking drive bellows the water leaks in from the outside while the boat is in the water. It will leak into the boat even if the engine is off.

Not to say you don't have a drive bellows problem, but the symptoms and conditions you describe are not from that.

There are casting plugs on the back of the engine behind the flywheel, hard to get to with the engine in the boat.

A cooling system pressure test can help find a casting plug leak.

 

[Bondo]

Re: 1981 Mercrusier 140 hp Leaking Water

Ayuh,.... It sounds like Freeze Damage....

You'll need to pull the motor to get at those Coreplugs...

 

[Brent M.]

Re: 1981 Mercrusier 140 hp Leaking Water

Whats involved in pulling the engine? I have looked and it looks like to me that ther are two bolts on the front motor mount of the engine and two on the rear motor mount. How many bolts if any are there on the rear of the engine where it connects to the outdrive?

 

[maverick3656]

Re: 1981 Mercrusier 140 hp Leaking Water

buy you a repair manual it will tell you everything you need to know and then some. they are around $30. they are worth the money.

 

[chiefalen]

Re: 1981 Mercrusier 140 hp Leaking Water

To pull that motor first disconnect the battery. Disconnect all the wires so it can be lifted free of the bell housing.

If i remember right there are 3 bolts on each side that connect the motor to the bell housing. The bell housing does not have to come out. There are 6 screws that hold on the flywheel cover got to come off.

Fuel hose got to be disconnected, from the fuel pump.

Throttle cable removed from the carb.

Shift converter removed.

Maybe i missed something, anything thats connected to the motor that won't allow it to come free must be removed.

Now you should remove the drive, this will give you the chance to inspect everything.

You will need a fork lift or as i did it i installed a 2 x 10 across 2 trees in my backyard about 7 feet above the motor and with a chain hoist i lifted mine out.

Good luck!

 

[captian Ozone]

Re: 1981 Mercrusier 140 hp Leaking Water

I am a newbie here and could not figgure out how to place a new origional post. I saw a old reply by a user chiefmike58 that refers to a upgrade kit to stop the water pump seal from wearing a grove on a 224 3.7 merc 470 cam. Does anyone know of this and have a manufacturer / part number and contact onfo?

 

[Fishermark]

Re: 1981 Mercrusier 140 hp Leaking Water

captain Ozone - right above all the posts there is a button labled "create new post" - click on that and you are good to go!

 

[joeyr]

Re: 1981 Mercrusier 140 hp Leaking Water

i have a 77 merc (77 20 foot Grew)
I bought the boat about a month ago, the engine was dead. No turning over or nothing.

4 weeks later, I now have it in the water and running almost like a top. I only have one more problem and it's exactly as you describe. I had a lot of "freeze" damage on the engine (leak after leak) and this is the last one.

I will be pulling the engine shortly to get at it. Lucky my neighbour has a good setup for stuff like that.

I hope it a freeze plug and not a block crack. I will let you know and take pictures as I go. Maybe they can be some help to you.

Joe