Mercruiser 140 Overheated

[SFCNay]

I recently purchased a 1981 Stingray with a 140 Mercruiser. I am not extremely familiar with boats but am mechanically inclined. I dont have a lot of money and am trying to do this as cheap as possible and yes I do know that some of you are rolling your eyes right now LOL. I took the boat out on the lake and it seemed to run fine. It started ok and ran ok but then it started to overheat. I tried to limp it back into the ramp but the temp guage was close to pegged and I shut it off. When it cooled down some I tried to start it back up and nothing. Finally someone towed me back in. I ordered a new impeller kit and replaced the impeller and housing and all gaskets and plastic tube. The impeller was completely shot. Good news is now I have water going to the motor. Bad news is its coming out from one of the spark plugs while it is running. So I took it back out to the lake and then it......just seeing if you were still listening. Do you think that this is the head gasket? Where is the cheapest place to buy the parts and how hard is a head gasket to change? Any tips or links would be greatly appreciated. I am trying to make this work on a soldiers salary

 

[SFCNay]

Re: Mercruiser 140 Overheated

Also there is no water in the oil even after replacing the impeller. It does still start and run but water just leaks out of plug #1 and plug #1 only

 

[oops!]

Re: Mercruiser 140 Overheated

hi....welcome to i boats...

and thank you for your service

ok....first of all....im NOT A MECHANIC.
however it sounds like you may have a manifold leak...

the manifold on a 4 cyl motor holds the water...intake and exaust.....first thing i would pull that and pressure test it. (i do not beleive that the over heat caused it to break) the manifold has to come off before the head comes off any how.....so you have nothing to loose ...right?

if the manifold is good....then you know its good and can move on to the head gasket....but you really had to had cooked it before the gasket goes....thats not alum....but cast.

just do a search to find out how to pressure test a manifold.....
also......the adults only section here is fantastic info for marine dyi's

cheers
oops

 

[oops!]

Re: Mercruiser 140 Overheated

oh.....by the way.....as far as cost.

it will be cheap unless that manifold is toast....(thats a minimum of 400. possibly a deal somewhere used.)

you will first need marine exhaust gasket and a carb gasket (about 15 bux for both) ... book an after noon to remove....test and replace.

if the pressure test on the manifold is good....and you proceed to the head gasket.....

then you will need a valve cover gasket (cheeeeep) and a head gasket about 35 bux....
book another after noon to do this.....to a pro....its just a few hours....to a dyi.....its at least double or triple.

you will also need to have a torque wrench as the head bolts must be done in sequence to 55 lbs .

 

[Bondo]

Re: Mercruiser 140 Overheated

Ayuh,... Please define alittle Better about water coming out of sparkplug #1....
There's No water in a sparkplug...
Sooo,....
Is the water coming from a crack NEAR sparkplug #1, or is it coming from Cylinder #1 with the sparkplug out,..??

 

[bigskiohio]

Re: Mercruiser 140 Overheated

if it is a 4 cyl , the manifold on otherside of engine the the spark plugs or am i wrong?

 

[SFCNay]

Re: Mercruiser 140 Overheated

The water was coming from the plug hole as if the plug itself did not have a good seal. This was WHILE the engine was running. When I pulled the plug and turned the engine over it spewed water from the plug hole. No water coming from the other cylinders and they all seem to be making some decent compression. Dont have a compression tester to get actual readings but I will get one if I need to. I just assumed that at a minimum the head would have to come off anyway so no point at this time. The plug wires look like they were melted at the boots so I know that the motor must have gotten pretty hot. The oil is clean and doesnt have any water in it. What should I be looking for when I pull the head? Yes the manifold is on the other side of the motor from the spark plugs.

 

[cr2k]

Re: Mercruiser 140 Overheated

You need to pull the head and have it checked. That is not right nor is it even remotely no so bad. It is serious.

 

[SFCNay]

Re: Mercruiser 140 Overheated

I am definitely pulling the head, but what should I be looking for? I think that we have all established that it aint right unless Mercruiser has developed a new way of cooling thier engines by shooting water through the cylinder that we dont know about yet. I would like to try the least expensive things first and try to reslove the problem without making it worse

 

[Bondo]

Re: Mercruiser 140 Overheated

Well,... Obviously, there should be No water there...
So,.. You've gotta pull the head...
Be looking for cracks, or any other somethings that don't look right...
Then bring the head to a machine shop for their inspection,+ rebuild...

 

[bomar76]

Re: Mercruiser 140 Overheated

I am definitely pulling the head, but what should I be looking for? I think that we have all established that it aint right unless Mercruiser has developed a new way of cooling thier engines by shooting water through the cylinder that we dont know about yet. I would like to try the least expensive things first and try to reslove the problem without making it worse

The least expensive thing would be to drag it out by the road and hang a for sale sign on it.
There is NO least expensive thing you can do to solve water shooting out of a spark plug hole.
You ARE making it worse by leaving it with water in the cylinder while you try to conjure up some 3? solution to a major problem.

 

[cedarjunki]

Re: Mercruiser 140 Overheated

The least expensive thing would be to drag it out by the road and hang a for sale sign on it.
There is NO least expensive thing you can do to solve water shooting out of a spark plug hole.
You ARE making it worse by leaving it with water in the cylinder while you try to conjure up some 3? solution to a major problem.

take it from a once young, stupid, cheap sob......just pull the head and atleast bring to have checked...about 50 or 60 bucks in my area.... but beats the price of 3 or 4 head gaskets and alot more unnecessary damage... and alot of hair pulling because you cant see that hairline crack....
have the manifold checked the same time.....

wait.... im still young :/ and cheap too but not so stupid anymore thanks to everone here!

 

[SFCNay]

Re: Mercruiser 140 Overheated

So pull the head (which by the way I think that I have already established that I was going to do) take it to a shop and have it checked out. Check the manifold at the same time and make sure it does not have any cracks by pressure testing it. As for bomar (The least expensive thing would be to drag it out by the road and hang a for sale sign on it.There is NO least expensive thing you can do to solve water shooting out of a spark plug hole.You ARE making it worse by leaving it with water in the cylinder while you try to conjure up some 3? solution to a major problem) Have you been reading this thread? I suppose you would want me to what? Pull the motor right now and replace it ith a new one? Buy a new boat? Thanks to everyone here who has actually given me useful advice. There is water in the cylinder. I have no intention of letting it stay there any longer than necessary. I have tried to be as honest as I can here to get the best feedback that I can. If you are going to take what I tell you and throw it back at me dont bother. I AM trying to do this on my own. If I was rich I would have bought a new boat and we wouldnt even be having this discussion. Thanks again for the constructive responses and the help

 

[cedarjunki]

Re: Mercruiser 140 Overheated

I AM trying to do this on my own. If I was rich I would have bought a new boat and we wouldnt even be having this discussion. Thanks again for the constructive responses and the help

hope you didnt take what i said as being rude.....id much rather see anyone fix there own than pay out of there a~~ to have it done... everything i have done has been on my own with the help from this forum....i just wish i would have stopped and got mine tested at the beginning...but i am pigheaded!.good luck and hopefully its not the head, there getting harder to come by up here...

 

[bomar76]

Re: Mercruiser 140 Overheated

There is water in the cylinder. I have no intention of letting it stay there any longer than necessary.

So, how long do you think it's necessary to leave water in the cylinder to rust it out? It's been at least 3 days now.

I intended what I posted as a wake up call to you (which you obviously didn't understand).

You have a cylinder full of water and you were fishing for a cheap easy solution.

Good luck.

(rust never sleeps)

 

[SFCNay]

Re: Mercruiser 140 Overheated

Thanks for the wake up call. Just kind of assumed that it would come with something constructive. Guess that I missed that part of the forum. cedarjunki I certainly didnt take anything you said as rude. In fact I found it helpful. I have pulled the head now (at the earliest opportunity that I could BTW) This is the second day that it has had water in it and It takes a big man to admit when he was wrong but here goes......there was water in the cylinder. I know, I'm as surprised as you bomar76. It appears that the water was just in cylinder #1 as there was....wait for it.......rust in that cylinder. Very little surface rust, guess I got it just in time. I am looking to take it to a shop tomorrow and have the head and the manifold checked out. Any idea how much I should be looking at? I have approximately 3?

 

[SFCNay]

Re: Mercruiser 140 Overheated

Just got a call from the shop. Head is cracked Thanks for all the advice. I would have been REALLY frustrated had I just changed head gaskets and tried again. Anybody know of a cheap (and of course that is a relative term so as not to offend anyone) place to buy a rebuilt head. My wife has cleared me for more than 3?

 

[cedarjunki]

Re: Mercruiser 140 Overheated

http://cgi.ebay.com/ebaymotors/140-...8139224QQptZBoatQ5fPartsQ5fAccessoriesQ5fGear


not sure where you are but shipping is 33.00 for me......thats cheaper than the free head gasket!

 

[SFCNay]

Re: Mercruiser 140 Overheated

cedarjunki you rock!!!!!

 

[cedarjunki]

Re: Mercruiser 140 Overheated

i couldnt find any when i needed one 2 years ago!! i ended up driving an hour to a boatyard and paying 125.00 for a nasty looking, untested one and had to buy another headgasket....grrrr