First boat! 2.4L 200hp Merc advice needed!

[wrightjd95]

Intro
Hello all!

I've bought my first boat my boat! Although it is not a bass boat I noticed this is that place for these outboards so I was hoping for some advice. I got the boat for a steal. It was very cheap and there is no problems whatsoever with the boat its self. It's a 1996 maxum 17ft.


Outboard

Powerhead is a bit of another story. Mercury 1987 2.4L 200hp Carb - serial 0B197982

It starts up easily and ran okay. It sounds like its firing on all cylinders but the boat only got up to 30mph. The problem is the compresssion and thus lack of power.

Compression results:
results in psi

Port top:	76	Starboard top:	75
Port middle	85	Starboard middle	90
Port bottom:	85	Starboard bottom:	75

I was thinking this was probably just due to the age of the engine. Although I discovered a worrying sign which was that the oil injection mixer lever had become disconnected. So it looks like the engine had been running on an incorrect oil lean mixture.

Other than that the engine looks to be in good state.

I'll try seafoaming it once my muffs arrive. Hopefully that'll increase the compression. I may get a boroscope to have a look at the internals. I'm worried about the chrome plated cyclinder walls, because if they arn't in good condition it'll be a lot more expensive.

What're your suggestions? Will it need a full rebuild?



Many thanks!

James

[Radeleur]

I have an 86 Blackmax 200 as well as an 88 Mariner 200...both had compressions between 115-120 each. From what I have been told is that it should be within 10% from highest to lowest. Your high to low is 15 psi difference. Now, I am not a mechanic, but I think you make be looking at a rebuild. Not gonna be cheap. Mercury pistons rings are like 300 bucks alone. Cylinder sleeves are like 120 plus the machine work. Gasket kit is in the neighborhood of 200. Local shop rate is 120/hr. Since you are into it that far should probably replace the rod bearings and cages at about 55/eachx6 so about 330. Needle bearings about 70. If your pistons are good that can save you but if not they are about 330 for the starboard side and 636 for the port side but the piston comes with the wrist pin and rings. These are all US prices. Yours may be completely different.


Only reason I know this as one of my motors has some cylinder scoring and I am having to look at it myself.

[JOE54]

+1 compression is low if checked correctly ,yes possibly needs rebuild , theres many topic here about conp testing

[leonreno]

You say mixer lever was disconnected, are you sure the oil injection is still functional or has it been converted to premix? Hopefully the seller told you this if he had changed to premix and you aren’t running it with no oil in the gas.

[wrightjd95]

You say mixer lever was disconnected, are you sure the oil injection is still functional or has it been converted to premix? Hopefully the seller told you this if he had changed to premix and you aren’t running it with no oil in the gas.

Good point! That would make sense, and there is no remote oil tank. I was running it with the gas already in the tank. The father (owner) was not present when viewing the boat, it was the kids who were there for the viewing and they weren't too knowledgeable. I'll have to double check this one.

What are the pros and cons of oil injection vs premix? I hear it's quite debated?

+1 compression is low if checked correctly ,yes possibly needs rebuild , theres many topic here about conp testing

Okay, one thing I need to try is a new battery, the one that came with the boat is a bit decrepit. Could be that it's not cranking fast enough to build that compression. So I'll get that, and I'll also try getting rid of those carbon deposits.

I have an 86 Blackmax 200 as well as an 88 Mariner 200...both had compressions between 115-120 each. From what I have been told is that it should be within 10% from highest to lowest. Your high to low is 15 psi difference. Now, I am not a mechanic, but I think you make be looking at a rebuild. Not gonna be cheap. Mercury pistons rings are like 300 bucks alone. Cylinder sleeves are like 120 plus the machine work. Gasket kit is in the neighborhood of 200. Local shop rate is 120/hr. Since you are into it that far should probably replace the rod bearings and cages at about 55/eachx6 so about 330. Needle bearings about 70. If your pistons are good that can save you but if not they are about 330 for the starboard side and 636 for the port side but the piston comes with the wrist pin and rings. These are all US prices. Yours may be completely different.








Only reason I know this as one of my motors has some cylinder scoring and I am having to look at it myself.

Aighty, then it seems like if I can't get the compression up we're then it'll need a rebuild. I still have it in the budget. I spent 5,000 usd on the boat, not sure if that was a good deal or not? You'll have to tell me? Boat is at my place down in Mexico (in a resort town). I'm British though.


I found rebuild kits for 900 usd which include:


6 Pistons
6 Piston ring sets
6 Wrist-pins with circlips
6 Wrist-pin bearings
6 Connecting rod bearings
1 Powerhead gasket set with seals




I'll do the rebuild myself, just not the machining. Will post progress here. The only thing I'm worried about is the condition of the block. What can I do to restore it? Resleeve or rechrome?




Thank you!

[leonreno]

If oil injection is already removed probably best to leave it that way. I prefer to keep mine but I don’t think I would add it back to a motor that it was already removed.

Here is a link on how to preform a compression test correctly:
http://www.bbcboards.net/showthread.php?t=267446

A good fully charged battery is essential. Redo the test according to that link and see if the results change.

[maineidyl]

Make sure you are checking compression correctly and with a decent tester.
Tom

[JOE54]

chrome cyls possibly dont need anything , scored ones will need sleeved, if link on oil pump is off mixture will go full 50;1 when arm rotates

[wrightjd95]

chrome cyls possibly dont need anything , scored ones will need sleeved, if link on oil pump is off mixture will go full 50;1 when arm rotates

Great info! So you think I could get away with just new cylinders? I suppose I won't know until I take the engine completely apart. Nice failsafe about the oil mixer arm!

I spoke to the previous owner - he just ran premix. However, the injection systems seems intact. I will run it premix until I get a remote tank. Although, I reckon the oil pump will have been damaged from running dry?


Question, if the compression is that low I imagine it's quite bad to continue running it like that?

Currently waiting on my paycheck to before I get a new battery and rebuild kit.

[JOE54]

better wait on kit until its torn down and inspected

[wrightjd95]

Anybody got the manuals for this model or know where I can get them? I don't think the one I have is fully intact.

Thanks.

[JOE54]

merc dealer

[timscryan]

If it starts without a hassle and has decent low end power, the compression tester is probably shit or the method for testing was probably not correct. If it starts like crap or has no low end power, pull the heads and examine the cylinder walls above the ports. Scoring is not good, porosity is normal. The chrome will be smooth as a babies ass if its in good condition.

[EuropeanAM]

If oil injection is already removed probably best to leave it that way. I prefer to keep mine but I don’t think I would add it back to a motor that it was already removed.

Here is a link on how to preform a compression test correctly:
http://www.bbcboards.net/showthread.php?t=267446

A good fully charged battery is essential. Redo the test according to that link and see if the results change.

Before going any further on this, I would strongly recommend you read through the link in the above quote, and REPEAT THE COMPRESSION TEST following precisely those instructions.

[wrightjd95]

Been a while since I had the chance to work on the boat.

Redid compression test, with warm engine with better battery 950 cold crank amps. I couldn't find anything better. I may run two of them in parallel as I hear these engines will need 1150 amps.

Here are the results:

Left port side:

Top 95

Middle 105

Bottom 105

Right starboard side:

Top 90

Mid 110

Bottom 95

The right top and middle seem a bit concerning since there is a 20 psi difference, 90 psi seeming low. I will try engine cleaners and etc to bring this up as well as the new bat.

Is 105 psi okay? How much will this affect HP?

Additionally it seems the engine hasn't had a ethanol upgrade. So I imagine that is causing the power issues.

I took the boat down from 6700ft elevation to sea level, which is its new home. So it was pretty hard to start, it will be running very lean. There doesn't seem to be any idle adjustment screws on the V6 carbs. I imagine tuning is achieved by rejetting which I'll have to do when the carbs come off for rebuild.


There was an issue with the coolant system as there was no water coming out the tell tale. I imagine the engine suffered overheating a few times. I replaced the pump and it fixed the issue. Replacing it was a joy. No corrosion at all. It has been a lake boat stored indoors its whole life so it came apart as if it was new.
reassembled with marine grade anti corrosion thread compound.

[JOE54]

rejet for low alt. , start up, warm up and recheck compression on all six use FAQ on checking comp , 850 -900 should be plenty batt for it

[wrightjd95]

rejet for low alt. , start up, warm up and recheck compression on all six use FAQ on checking comp , 850 -900 should be plenty batt for it

Thanks I will do!



Here is a video of it running. Smokey because the fuel is about two years old. I'm sure that it not doing it any good.

Oh and I used a tarp with a crate to run it in water as this engine uses a tremendous amount of water and quicky overwhelmed my hose.

[JOE54]

why even start it on that fuel ????????be careful youll burn water pump up

[wrightjd95]

why even start it on that fuel ????????be careful youll burn water pump up

I was pretty sure it had fuel stabilizers added. Yeah I just replaced the pump, that was the test on of it really. Engine wasn't peeing before.


I have a question. Which jets do I need? Is there a specific type? I know I can look up the manual what size I need, but I've never actually ordered jets before.

Edit: Looks like I have to order specific jets to this outboard from a parts supplier?

[JOE54]

need WH - number on top of carb / mounting flange , yes there is and you an look in Manuel should have part number in manuel