Opinions on Mercury 150? Low compression.

deputydawg · #1 January 28th, 2009, 09:16 PM

I am looking at buying a 1990 Sea Ray 180 Bowrider. It has a Mercury 150, the picture looks like it says Black Max on the side. I have not seen the boat in person yet, only pictures. The dealer says one cylinder was "scorched" resulting in excessive cylinder leakage and low compression. Not sure what scorched means.
My question is what is everyones opinion on this outboard? Are there any common problems associated with this engine? Any ideas on what might cause one cylinder to have low compression? And finaly are there any online manuals I can check out before I decide to go look at the boat?
I am looking for a project boat. I am a mechanic, and have a friend who knows marine mechanics so the repairs are not a problem. Also curious if anyone else has run into this kind of problem and if an overhaul would fix the problem with the low compression.

Thanks.

Faztbullet · #2 January 28th, 2009, 09:52 PM

If it not locked up or thrown rod or piston thru block it can be fixed. The 1990 came two ways the 2.0 liter 150 and the 2.4 Xr4. Both are good engines and overhaul should fix engine. You will spend around $1200-1600 to get it right.

deputydawg · #3 January 28th, 2009, 10:45 PM

Thanks for the reply. I am waiting now for an E-mail from the dealership mechanic as to specifics on what is wrong with it.
Is that 1200 to 1600 include labor for a marine mechanic to do the work, or is it only parts and machine work?

Eshaw150 · #4 January 28th, 2009, 10:50 PM

that should be about the whole shabang

Faztbullet · #5 January 29th, 2009, 12:42 AM

This is for parts only,if in my shop labor would be around 650.00 12hr @ 55 per hour
6 pistons @ $100.00ea = 600.00
1 gasket set@ $100.00
1 misc bearings @ 250.00
1 impeller @ 25.00
3 carb kits @ $ 20.00=$60.00
1 misc sealers/cleaners= $35.00
Boring 6 @40.00ea =$240.00
misc shipping $30.00
grand total= $ 1330.00

deputydawg · #6 January 29th, 2009, 02:36 AM

Thanks for the information.
Will have to see what the boat and engine look like, and see if they come down a little more on the price.
The dealer that has it has a very good reputation, is one of the biggest dealers in the area, and has been around a long time. I am comfortable taking their word on the condition of the outboard but knowing a general price range will help me negotiate the price.

Chris1956 · #7 January 29th, 2009, 09:36 AM

Deputy, You can just bore the scored cylinder, and save a few $.

Whatever route you take, you need to fix the problem that caused the scoring. It is usually caused by overheating or lean fuel mix. A new impeller( I would install new thermostats as well, for good measure) will fix the overheat problem, and cleaning the carbs should fix the lean condition. Check the condition of the oil pump drive gear, while the motor is apart, to make sure it is within tolerance.

deputydawg · #8 January 29th, 2009, 11:18 AM

If I would just bore the one cylinder would this cause the engine to run rough? Or would there be a possibility of sleeving the scored cylinder?

I am still waiting on the service manager from the dealer to contact me with more details of what is wrong with this.

I am definately interested in the cause of the scored cylinder.

Faztbullet · #9 January 29th, 2009, 11:38 AM

If it has overheated the other cylinders are going to be scuffed or out of round. It is a 20 year old engine that has likely pulled skiers and it is due for the other cylinders to be serviced. That engine can be bored up to .030 on the 2.4 and .060 on the 2.0.A oversized pistion weighs the same as a stock piston so you can run std and oversize together with no problem.

QSS · #10 January 29th, 2009, 05:35 PM

Hey faztbullet i was just reading this thread and didn,t no you could do that. run different size pistons together.. thanks for the info.. will help us with our problem...