Need help with my manifold

[Butt-Ugly]

I have an old boat (1978), with a merc 140 (label on rocker cover), it is FWC, and the serial number is 3695234.

I have only had it for one and a half seasons and keep it moored all year in the chuck. Late last November I was going to head off fishing and had a hard time getting it started. When I finally did get it running, it sounded horrible like it was ony running on 2 or 3 cylinders. I pulled off the doghouse and looked around the engine and had noticed little bubbles of water at the mating surface of the manifold and head between exhaust port 2 and 3, so I just shut it down. I haven't taken it out or ran it since.

I had waited till the weather warmed and pulled it out of the water to get to looking into the problem recently. I was assuming that at the least the gasket is shot. I had not noticed any rise in engine temperature on any of my outings previous to when the problem presented itself. I do keep a good visual on my temp and vacuum while running.

I have pulled off the carb and manifold now, and as I expected the gasket is crumbling where I had noticed the bubbles and was probably leaking in other areas as well. The manifold water passages were also pretty plugged up with crap. I started cleaning out some of the gunk, but am unsure whether it is even worthwhile putting this manifold back on with a new gasket set, or to just replace it.

I did look around on the net to see what it will cost to replace the manifold, but none of the pictures of the manifold that is supposed to fit my engine look like the one I have. Is it possible someone has put a merc 120 manifold on this 140? Are they interchangeable? Hopefully these pictures will help to explain better the info I've given.

The boat was cheap, old and ugly, which is why I named it Butt Ugly. It does have low compression, but they are all pretty equal. I don't think it's really worth throwing much money at it, so I'm really looking to just maybe find a bandaid solution to get another season or two out of it. I have a new kicker on it to get me home when the engine finally decides it's had enough.

Suggestions on what to do, any help identifying the manifold, and any help diagnosing other possible problems from my pictures are greatly appreciated.

 

[Don S]

Re: Need help with my manifold

You need an engine. Looks like the riser and manifold failed (Rust and corrosion over time) and allowed water into the cylinders. They are probably equally rusty.
Pull the head and look.
Everything you have pictured there, is JUNK

 

[Bt Doctur]

Re: Need help with my manifold

Cyl #4 looks like it`s been on water for some time.
like Don says, pull the head to check.

 

[Bondo]

Re: Need help with my manifold

Ayuh,......

You've got an Anchor,.......

 

[Butt-Ugly]

Re: Need help with my manifold

Thankyou for the very quick replies. This forum is amazing!

You need an engine. Looks like the riser and manifold failed (Rust and corrosion over time) and allowed water into the cylinders. They are probably equally rusty.
Pull the head and look.
Everything you have pictured there, is JUNK

Ouch, my boating days may be over then. I simply can't afford a new engine, or another boat right now for that matter. That's what I get for trying to be a po'boy playing a rich mans game!

Ayuh,......

You've got an Anchor,.......

I already had an anchor! What am I gonna do with two?

--------------------------------------------------------------------------

After my initial problems and fixing the things that weren't working well when I first got this boat, it had been running really good until the problem on that last fateful day in Nov. I put 130 hours on it since I had installed an hour meter back in June. It was running great and was used everyday for a couple hours in the last two weeks pulling prawns until I had the problem that had me put it to sleep til the weather got warmer to tear it down for a peek.

Does the water problem on cylinder 4 really look like it was going on for some time, or is it possible it was just a catastrophic moment and the rust in the ports simply from water sitting since november? The leak I saw was only at exhaust port 2 & 3 when I shut it down, but that doesn't mean the gasket wasn't failing in other areas as well over time. I am just asking, not arguing.

I will continue to tear it down further and pull the head to look and see what else I might find going on in there. I can post a couple more pics of what I find when I get that done.

As to the manifold itself, am I right in assuming it is a 120 on my 140?

Once again, I thank you all for the speed in which you have replied!
(Don't any of you guys work?)

 

[Don S]

Re: Need help with my manifold

I would guess your gasket between the manifold and the elbow (riser) failed. Maybe because the riser or manifold gasket surfaces had deteriated. They sure don't look very good in your pictures. But with all the rust in the ports, I KNOW the cylinders and valves look the same.
Yes, it looks like a 120 manifold.

(Don't any of you guys work?)

I do, but went into work this morning opened the place up and looked around, closed back up and left.
No desire to deal with it today.

 

[Butt-Ugly]

Re: Need help with my manifold

Ok, so I've had the time to get back to the engine and get the head pulled for a peek inside and see what else is going on in there.

I can post some other close-ups of each chamber if necessary.

And here is a couple shots of the cylinders. There was no water sitting on top of any of the cylinders, but #4 does have some colour to it, but it rubs off easily with your finger and there is shiney metal below. The coolant was clean and green, and the oil shows no signs of water and is still nice, clean and transparent.

Would I be ok if I just cleaned it up and put it back together with new gaskets, and replace the manifold and riser?

 

[Haut Medoc]

Re: Need help with my manifold

Ok, so I've had the time to get back to the engine and get the head pulled for a peek inside and see what else is going on in there.

I can post some other close-ups of each chamber if necessary.

And here is a couple shots of the cylinders. There was no water sitting on top of any of the cylinders, but #4 does have some colour to it, but it rubs off easily with your finger and there is shiney metal below. The coolant was clean and green, and the oil shows no signs of water and is still nice, clean and transparent.

Would I be ok if I just cleaned it up and put it back together with new gaskets, and replace the manifold and riser?

That's what I would do....
You have nothing to lose....
I've seen far worse & I'm surprised it really doesn't look that bad considering the condition of the manifold....

 

[Maclin]

Re: Need help with my manifold

I recommend checking for any warpage on the block deck surface and all head mating surfaces with a straight edge before you decide to just put it all back together like it is. New gaskets won't last very long if the facing surfaces are not completely flat.

What do the valve stems, seals, guides, springs and retainers look like?

 

[rocket1968]

Re: Need help with my manifold

I agree, what is the cost? A few plugs, some oil, and gaskets? Keep us posted, I also own an old boat and continue to read here since I know I am on borrowed, (extremely) borrowed time. I inherited a boat and have had a blast over the past few years with only maintanence, but those days are numbered.

 

[Butt-Ugly]

Re: Need help with my manifold

Upon a much closer look at the head, I have also found a small crack in the head gasket right between the center of cylinder 3 and 4. Will a common steel ruler work for a straight edge to check the head for warp or do I need to get a special tool for this?

I'll need to rent or borrow a valve spring compressor to disassemble the head for a further look into the stuff in there. If it's not too bad, how do i go about cleaning up this stuff for reassembly? I can wire wheel the carbon out of the combustion chambers, but how do I treat the cylinders and the carbon on the top of the pistons?

Is there a guide available online to help me through this?

 

[Bt Doctur]

Re: Need help with my manifold

The maifold pics dont match the engine pics,you may have caught a bad riser just in time.It does look like some intrusion but the head looked decent.

 

[Butt-Ugly]

Re: Need help with my manifold

Don't any of you guys work?

I do, but went into work this morning opened the place up and looked around, closed back up and left.
No desire to deal with it today.

I know that feeling well! I did exactly the same thing today. Felt like my time would be better spent mucking around with my engine today.

The maifold pics dont match the engine pics,you may have caught a bad riser just in time.It does look like some intrusion but the head looked decent.

Sounds like the pendulum is starting to swing more towards the positive side of this situation. I will just need alittle guidance on the procedures required to clean up the mess and hopefully back together to run for another season or two. Should I still disassemble the head? How do I clean out the cylinders? I am putty in the hands of the master mechanics on this board!

 

[tommays]

Re: Need help with my manifold

Well

You have a FRESH WATER COOLED 140 which is really really RARE

And i think most thought your block and head would be as bad as the manifold from the saltwater intrusion

 

[HT32BSX115]

Re: Need help with my manifold

YOU SIR, are pretty lucky! It appears you caught that thing in time! Most of us are not so lucky....most of us catch things catch things like that WAY too late when we gamble!

The damage is not all that great. I think if it were mine, (depending on how many hrs are on the engine), I would run that head over to a local reputable machine shop and get the valves done, get a new manifold/riser (replace the exhaust flapper if it has one), new gaskets, replace the raw water pump and put it back together! You'll get more than a couple seasons out of it!

Cheers,


Rick

 

[Maclin]

Re: Need help with my manifold

Solely based on what I can gather from the pics, the pistons and cyinders were spared somehow. I agree that you caught it earlier than most. I also agree with HT32 that refreshing the head now is a good option.

If you are entertaining a rebuild at some point or even now due to this I would get the head refreshed now. The shop will make sure it is useable then mill the surfaces to get them straight again and regrind or put in new valves, etc. Put it back together and check compression dry, listen with a stethoscope for air leaking past the rings.

If the compression was ok on the engine before this then the refreshed head will work ok. If the engine was worn in some and the valves and rings both were leaking compression then with a new head you will get more oil blow-by from the worn rings.

I guess I am thinking refreshed head, new manifold and risers, check the compression. If compression is bad then stop and plan on a block rebuild. If compression is ok more or less then go with it and see how long that runs. Again, this is solely based on the pics, the cylinders there look like they have life yet to me.

 

[Don S]

Re: Need help with my manifold

If I were you, I would go buy ONE lottery ticket. It HAS to win. Anyone with a manifold like that and the engine is good as yours looks has to be the luckiest guy in the world.

 

[Maclin]

Re: Need help with my manifold

I concur!