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1999 25hp Mercury 2 stroke help needed

R

rpweatherford

New member
I am new to this forum, as I just found you today. I have a problem with a 1999 2 stroke Mercury 25hp. I got in a hurry going to an afternoon fishing trip with the kids and forgot to put oil in the gas. Needless to say, it locked up. Once I got it home I sprayed oil in the cylinders , through the exhaust manifold openongs, and freed it up. There is visible scoring on the top cylinder and the top piston rings are locked up. It runs now but appears to run on 1 cylinder. This is a Mercosil block, which from everything that I read is the only type of block that can be bored or honed.

I took it to a local shop and was told that I would need a rebuilt shortblock with rings and pistons. The shortblock will cost $800 and another $3-$400 labor. He did not want to even talk about boring my block.

My question is why noy bore my mercosil block, since it was made to be bored?
My other question is where can I order a manual and rebuilt kit for this motor ?
I have plenty of experience rebuilding 4 stroke engines and my father is retired diesel heavy equipment and auto dealership mechanic.

Give me your input
 
It was NOT made to be bored out for o/s pistons and rings.--------------The bore was specially treated with a chemical process ( and heat ) to obtain a very hard ceramic coating. This coating should never wear out under normal operating conditions.--------The motor should be taken apart for a look see at the parts.-----Maybe new pistons and rings ( standard size ) is all that is needed.
 
Hello rpweatherford,
Not sure if you have done anything with your motor yet but I also have a 1999 25 hp mercury 2 stroke with the Mercosil cylinders. Both my cylinder were scoured when I bought the boat so I feel your pain. Mercosil cylinders can be bored up to .40 over. There is a shop in Michigan that does bore the Mercosil blocks (the only one I found). It’s a blind bore and it takes a special tool to bore these blocks. By the way this shop was recommended to me by Mercury themselves. I called the shop and they bore these blocks a lot. I stripped my block down and shipped it off to their shop in Michigan. That only cost $25.00 from Kansas. The shop bored both cylinders .30 over, and I had them ship new piston, rings and gaskets back with the block so I can reassemble the engine. That bill was around $380.00. I have the all the paperwork so if you’re interested in doing this, let me know and I will get you the info needed.
 
LTH said:
Hello rpweatherford,
Not sure if you have done anything with your motor yet but I also have a 1999 25 hp mercury 2 stroke with the Mercosil cylinders. Both my cylinder were scoured when I bought the boat so I feel your pain. Mercosil cylinders can be bored up to .40 over. There is a shop in Michigan that does bore the Mercosil blocks (the only one I found). It’s a blind bore and it takes a special tool to bore these blocks. By the way this shop was recommended to me by Mercury themselves. I called the shop and they bore these blocks a lot. I stripped my block down and shipped it off to their shop in Michigan. That only cost $25.00 from Kansas. The shop bored both cylinders .30 over, and I had them ship new piston, rings and gaskets back with the block so I can reassemble the engine. That bill was around $380.00. I have the all the paperwork so if you’re interested in doing this, let me know and I will get you the info needed.
Click to expand...

I have the same motor and need the info. on the shop you used. Thanks
 
LTH said:
Hello rpweatherford,
Not sure if you have done anything with your motor yet but I also have a 1999 25 hp mercury 2 stroke with the Mercosil cylinders. Both my cylinder were scoured when I bought the boat so I feel your pain. Mercosil cylinders can be bored up to .40 over. There is a shop in Michigan that does bore the Mercosil blocks (the only one I found).
Click to expand...
I sent you a PM, I'm in the same boat too and could use the info on the shop
 
I too have a Mercosil block that needs some work. Not sure if needs boring, but would like to send it off after reading this thread. Anybody have any info on the shop in Michigan? If you do, either post it or pm me. Thanks in advance.

Sparky
 
If you haven't already gotten your engine fixed, Nichols outboard in Soddy Daisy, TN is the guy to go to for machine work on Mercury engines. They bored my '96 25 hp. I bought pistons and gaskets at Promarine in Palmetto, FL. The total was close to $400 doing all the labor myself.
 
The truth is, it's more cost effective to order a new powerhead and have it installed, rather than rebuild the existing one. Your also rolling the dice by assuming that only the cylinder walls and pistons were damaged when this all occurred.
 
This post went inactive in 7/12 but good info. on the powerhead. When my 2002 115 HP 2 stroke quits I may just replace the powerhead because the 4 cycles are still crap on the power to weight ratio even after a dozen years to perfect them.
 
guyjg said:
This post went inactive in 7/12 but good info. on the powerhead. When my 2002 115 HP 2 stroke quits I may just replace the powerhead because the 4 cycles are still crap on the power to weight ratio even after a dozen years to perfect them.
Click to expand...

You should save for a 115 Optimax ;) They run nicely and do better on fuel than the 115 4 strokes.
 
I'm currently going through the same issue, will you please give me the info. I need for the shop in Michigan please?
 
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