1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hello again

My nephew had this engine for 4-5 years and used in salt daily. It has these bad symptoms.

A)Stops peeing now and again and then just steam followed by the overheat alarm. Have to rev it abit to get the pee stream back and alarm goes off.

B) Tries to Idle and eventually chokes it self out with it's own exhaust. Take cover off and it will Idle all day long.

Sounds like to me that the gasket and/or plate between the powerhead and the mid section seems like it has succumb to the salt and it letting the exhaust into the cooling area and vise/versa. The area between the powerhead and the mid section is visibly leaking exhaust/water from the crease.

1)Is there anyway I can get a Compression reading and test the engine to see if it worth to fix this engine? Wouldn't the head gasket be giving me a low reading when it"s compromised?

2)Can the gaskets on the water jacket on the back 2 cylinder banks be letting exhaust into the cooling area too? They don't leak any water though.

If I test this engine and it's worth to fix this problem, I'm going to need help and some tips on what to replace while I'm in this area, and how to get the powerhead off and the steps that follow. Im going to get him to get a manual too but I have never done this before and real life experience/trial and error experience will help me out BIG time.

Other than carbs seem clean and good and cooling stuff(Therms,Poppit,Pump) seems fine but im going to probably replace the cooling stuff after I get done with powerhead. They probably took a beating with this other issue. Power head was recently rebuilt before my nephew bought the boat so if everything checks out I think this engine has some life left in her. Also the oil pump plastic gear seems like the teeth didn't round off or is bad, we never get a oil alarm just a heat one.

I know I'm rambling abit but I really want to get this done for my nephew. He works his balls off making money with this boat daily. He knows I love learning and working with engines (Mainly outboards) so he came to me with this request and I told him iboats will give us the straight skinny on things. I'm excited about this and I hope we get the green light from you 'guys' to do this work. It will be fun to work with him and learn together!


Thanks,
DamianJP

PS: My dads '77 55hp Evinrude has this same problem and is waiting for me. This will be GREAT practice even though they are two different beasts.

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Man.You got my head spinning.
first off i would check compression. and go from there.
It sounds like there has been lack of maintenance.

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Well to sum it up quick

How can I test the engine to see if its worth fixing the head gasket?
Will a simple compression test do or will I get a false reading due to the gasket being damaged? And then we'll go from there.

There has been maintenance done. New water pump every year and the thermos and popits checked/serviced too.Carbs have never be gunked up because the boats is ran atleast 5 days a week if not more.
Just the boat stays in the water and never gets flushed.

Sorry If I made your head spin with previous post.


Thanks gain,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hi again

Well we just bought a 2006 Venture roller trailer today for $1000, what a good deal . We pulled the boat, but before we pulled it I took a compression test.
I took 2 sets of tests per cylinder one with throttle closed and one with throttle fully open. I cranked it till the gauge stopped reading.

Left cylinder bank facing motor from the back.
Top
130-140
Middle
110-120
Bottom
120-130

Right cylinder bank facing motor from the back
Top
130-130
Middle
130-130
Bottom
120-130

What do you guys think about the 110-140 difference? The 110 test went to 120 on the second test. Also it was overall a 10-20 PSI difference. And the gauge isnt a professional gauge.

We are grabbing a service manual soon.Will this manual go threw power head removal?

I got the number DO24019 on the stamped circle on the top of powerhead,but can't match or find anything on crowleymarine site for schematics. Was getting dark and had limited lighting might have to look at it again tomorrow .

My first time doing something this major on an outboard.
Any links on powerhead removal and replacing this gasket and/or plate would help alot. Also any help from your guy's personal experience with removing the powerhead would help BIG TIME .

I'm gonna do some research on here to get an vague idea on what I'm working with in that area.


Thanks again,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hello

I went to re-check the serial number on the circle stamped on top of the power head. It is D024019.
Now heres the kicker, I checked the number on the Transom area since we pulled the boat and it read 0D081422 on the sticker.

It seems mabey the powerhead was replaced? If so this is going to be a PITA to find what parts im going to need if I can't pinpoint what powerhead I'm working on.


Lemme know what ya find,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hey

Anyone know how to find out what power head I'm working on?

Please guys I really need help here, this can't be that hard of a project. I know there will be a few small stuff to look out for but thats why I need someone thats done this before to shed some light.

He uses this boat to clam,fish and transfer bait from port to port so the longer it is out of action, the more hurt it does.


Thanks in advanced,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

You asked if it was worth fixing the motor and the answer to that is a flat NO. The motor was run in salt water for 4 years every day and I don't care how well it was taken care of, there will be corrosion everywhere from between the lower unit and the power head to under the heads.
Check the tiller arm and swivel pin, if they're rusted out then count on spending 700.00 min to replace them. Your's are high carbon steel and the new ones are stainless.

I speak from experience in buying used saltwater motors for parts. They are cheap and for good reason.

However, if you have 2500.00 laying around and need a winter project then go ahead and tear it down and re-new it because that's what the work and parts will cost you at a minimum if you do it correctly.

That's my advice and it will probably be argued so take it or leave it, you won't hurt my feelings. Don't worry, I won't come back later and say "I told you so".

Oh yeah as far as what's wrong with it now? Sounds to me like a broken or chipped reed that went through #4. Probably some scoring on that hole.

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hey sschefer

I'm not looking to rebuild the whole motor. Just 2 gaskets. One in between the power head and the mid-section. The other is behind the exhaust chamber/plate on the back in between the two cylinders. Iv'e heard from two diffrent people and others on forums that the steam coming from the tell-tale is usually the gasket that goes bad from in between the powerhead and the midsection. Just gotta get it pissing and not overheating.

Just need some advice on what to do when I get the powerhead off and mabey what to replace when I'm in that area. Gonna grab a manual tomorrow.

Compression is good and its seems by 2 different(numbers don't match on the powerhead to the transom area plate) serial numbers that it was a replaced powerhead.

Carbs,waterpump,thermos,poppit all done in the last 6 Months or shorter.

I don't know what I described before that would make you think of a broken reed. But Thank You for your help/input, I need all the help I can get right now.


Thanks again,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Well..

I found out that the midsection/LU is 1991.
And the powerhead is a 1991 aswell.
Bon't they didn't come together, must have been pieced together since the numbers aren't the same.

Atleast I know what I'm working with. Also did more reasearch and it is either the water pump failing and/or head gasket. Strange thing is she's got great compression numbers but the visable gasket on the outside looks bad and is leaking water here and there. Probably with throw a new water pump in and see if that fixes it. Not a rebuild kit but the housing too,mabey the housing is warped.If not then I'll have to pop the head.


Little by little I *Will* fix this.


Thanks,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hello again

Got a crap load of parts today, but some on order though .

Just got the L/U dropped and the the old pump out and area prep'd.Poppit is removed and area prep'd. New thermos are in. All the rigging is removed from the engine. Ready for the nuts to be removed and then pop the head off.

Im replacing the head gasket and 5 seals/gaskets underneath the exhaust plate to make sure the exhaust is staying out of the cooling area. Anything tricky I should be looking out for?

http://www.mercruiserparts.com/Show...=140&bdesc=Exhaust+Manifold+and+Exhaust+Plate
Do I need part 27 from above schematic?


http://www.mercruiserparts.com/Show...ng&inbr=555&bnbr=180&bdesc=Driveshaft+Housing
Do I need part 27 from above schematic?

Sorry guys for all the questions but I really need some help on this project.

Thanks again,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Well a quick update

All parts are in and the dude hooked us up by letting us use the lifting eye for no rent charge, just gotta keep the box it comes in clean .

Ill try and get some pics tomorrow. We have this nice little system hooked up to lift the powerhead. 2 trees, a chain , and a come-along. I was gonna grab a used 2 ton lift off craiglist but the guy wont return a email, too bad it was for $100 too.

Waterpump and thermos are done. Rigging that lead to motor from console and tanks ,ect are off. Nuts holding powerhead are all off but 2 in front. Got a nice workbench that I lined up a gasket marked the holes and drilled out the stud area to lay the powerhead flat on so the studs can go threw. Man I wish I had a shop.

Now 2 studs gave me problems and came loose. 1 that holds power head on and the front one on lower unit. Gonna have to get them back in. Can't complain though atleast they didnt break off.

Gonna install poppet tomorrow and mabey pop the head off. First time im doing this so say a prayer.



DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Another update

Got the powerhead off! As you can see in the pictures the gasket on the top was real bad. Gonna replace all the seals and gaskets around this area.

Damn two trees and a come-along has got me worried but it seems to be working fine right now. Have to leave it hanging tonight and tomorrow I'm gonna attack it early.

Scrape and clean ,then work my way down to replace all the seals/gaskets down there(in the mid section).

This is REAL cool, Iv'e never done this to a engine before ,let alone an outboard.









DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Well...

Just got done sealing and torqeing everything. Waterpump,thermos,poppit, head gasket and other seals/gasket below that in the mid section. All is GOOD! Idling like a clock and pissing like a race horse!! Thank you to all who helped. I am really happy in how everything turned out. I was worried alittle more than usual because this isnt my rig and it's the first time popping the powerhead off and doing this much work at one time on a rig. If it was mine and could relax abit and if something happened I would be mad but its mine no one to worry about. Kudos to you guys who work all day long on other peoples stuff!!

Well another project(s) done and more stuff learned. Man this outboard stuff is ADDICTIVE!
The next thing that I want to do is find a cheap small outboard with a low cylinder and pop the head and learn to have it honed and I'll rebuild everything from scratch.


Thanks again,
DamianJP

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

i have a 98' 200hp mariner. basically the same as far as i can tell.
i have completely stripped down the engine.
i can not seem to find any more bolts???? i have even taken the lower unit off.
the power head does not seem to want to budge at all! i was reading your post seems like you was able to get your off. is there any "hidden bolts" that i am not aware of? any help would be greatly appreciated!

i tried to send a PM but i guess your box is full.

Re: 1994 200HP Mercury Offshore 2.5 litre Power head removal and advice.

Hey Bow!!

Well there were no hidden bolts but which ones have you got off so far? Two in the front tucked in there is the only ones really hiding.
Can you up load some pics?
There were 10 nuts/studs all together. 5 on each side.

For what its worth, i don't know how 'salty' your engine is but my nephews was bad. CRC Freeze-Out helped me out BIG time. Couple times I started to think to myself man it's demo time and started to reach for the dremel w/cut off wheel. Another round of heat and CRC Freeze was all it took.

Lemme know how ya make out and shoot me a PM anytime, my box is emptied abit to receive.


DamianJP