OMC / 200hp Johnson questions

This is about the V 21 that Reel looked at for me. It has a 1996 200hp Johnson Ocean Runner and the power head is suppose to have been replaced with a new one in 2006. When they did the compression check on it the numbers were:
#1 - 95
#2 - 80
#3 - 92
#4 - 80
#5 - 85
#6 - 76

The compression on #6 seems a little too low and when they pulled the plug on it Reel said there was a lot of carbon build up. Bare in mind this is suppose to be a new (well, ok a 1 year old) powerhead. Is there some kind of break-in time or service that is needed? What are the possibilities for the low compression? What might cause the carbon buildup? What should be looked at / checked out based on these numbers?

Reel did say when they took it out for a ride the engine ran good, but they think it might not be propped correctly since they couldn't get it above 4600 rpms.

Any help would be greatly appreciated. I'm seriously considering buying this boat, and want to make sure all things are addressed before I make an offer.

[Skools Out]

that hole 6 needs rings bad hole. i just re-ringed a 225 that had 89 to 90 on all cylinders but #3 and it had 77 well when i opened up the motor bad cylinder. burnt cylinder and rings. i'll get a pic of that piston. factory is 90 psi but*the reason for no RPM's it's the bad cylinder.

Thanks Skools! That brings up another question, though. If it needs new rings, should it be done on that whole side, considering the whole side is kinda low, or just that cylinder? And any idea of how much whatever the proper fix would cost?

Also, any thoughts as to why a "new" powerhead would burn the rings out so soon?

[Skools Out]

well may not have been broke in correctly with double oil first 25 hours and it should have all re-ringed while you have it open and that bad hole may need alot of honing to get the scoring out of the cylinder, plus will need new piston

it should have all re-ringed while you have it open

Just that side, or all 6 cylinders?

[macojoe]

All 6 cause if they have to hone to much they will have to put over size pistons.

NADA give that motor a $2400 vaule, tell him to take it off the price. Then you have the cash to fix or replace with something else, granted it won't be new but there are some nice motors for $2500, and in a couple of seasons you can upgrade.

When ever I look for a boat, I find the perfect boat and junk motor, or Great motor with junk boat.

Good Luck!

[phester]

I agree w/ what MJ just said.....those compression numbers do not sound to good for a "new powerhead"

[THEFERMANATOR]

I did a compression test on a 225 EVINRUDE before with only 3 hours on it from some side shop, the numbers were scary.
#1-95 #2-105
#3-45 #4-85
#5-85 #6-95

[macojoe]

This the reason I am not doing a test on mine!! I have the tool and all But I keep telling CB I don';t want to know as long as it runs I am happy!!
I don't need to know I have another problem this late in the game!!

[THEFERMANATOR]

MJ, so long as she starts good I wouldn't worry with it. CROSSFLOWS normally get hard to start when they get tired.