blown 1988 merc 150 black max

[blanchman77]

I have recently blown my 88 mercury blackmax. I only lost one cylinder and if i bore it .030 over it will take care of the gouges. What i am wondering is if the motor is worth rebuilding. Before the oil injection went it was a very strong running motor. also the cylinders were already .020 over before it blew on me. Can you have one cylinder .010 bigger than the rest or will that throw the balance of the motor off?? any input would be appreciated.
thank you

[thompy]

ive seen it done many times, but if it was me i would do all of them

[blanchman77]

i guess where i am at is i dont want to drop a grand on pistons and have it happen 2 months down the road. So i guess i have some thinking and research to do before i purchase the parts

[fyremanbil]

Boring just one is done all the time, even on high RPM engines. It won't hurt a thing.

[ChrisCarsonMarine]

I would bore all to 030 and replace all the pistons for 2 reasons,1.that's our policy on a Powerhead re-man(we don't repair and return),unless the motor is quite new or very low hours and the other pistons are like new and the customer insists.2,if the other pistons are 020 I would want the forged pistons out,and cast ones in,I'm not a fan of forged pistons for service motor mercs.

[rock]

Boring just one is done all the time, even on high RPM engines. It won't hurt a thing.

I agree 100%. I have seen motors, strong motors, with 3 different size pistons and 2 different sleeves (chrome and iron) run for many years. Unless you are building a world class racer, don't worry about it.
Rock

[blanchman77]

thanks for the input.Like alot of people i dont have tons of money to throw around on a boat. thats why i bought a 88.` so if i can get away with only spending a couple houndred it would really help. thanks again
kyle

[terry taylor]

I have recently blown my 88 mercury blackmax. I only lost one cylinder and if i bore it .030 over it will take care of the gouges. What i am wondering is if the motor is worth rebuilding. Before the oil injection went it was a very strong running motor. also the cylinders were already .020 over before it blew on me. Can you have one cylinder .010 bigger than the rest or will that throw the balance of the motor off?? any input would be appreciated.
thank you the piston mfg. I was told keeps over sizes regardless a consitant weight to each other thanks.

[rockbottom]

PAGE 8-52 " Oversize piston weight is approximately the same as a standard size piston. Therefore it is NOT necessary to rebore all cylinders in a block just because one cylinder requires reboring "
that manual is for up to 1991 inlines and v6's:thumbsup:
The evinrude manual says the same thing if I remember correct , steve


I have recently blown my 88 mercury blackmax. I only lost one cylinder and if i bore it .030 over it will take care of the gouges. What i am wondering is if the motor is worth rebuilding. Before the oil injection went it was a very strong running motor. also the cylinders were already .020 over before it blew on me. Can you have one cylinder .010 bigger than the rest or will that throw the balance of the motor off?? any input would be appreciated.
thank you