Just got some bad news from my mechanic. My 225 Johnson has a bad cylinder and he is reccomending going with re-man powerhead. My boat is a 82 223 Tournament in decent condition. What should my maximum dollar amount be before it becomes not worth doing with a boat this age?Is a re-man power head the way to go or should I look for a completely re-built motor? Lots of long faces at my house, we were going to put it in this weekend for the first time.
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looking for some advice
- Thread starter gradywhiteman
- Start date
Define "Bad Cylinder"
As for the age of the boat and what you'll spend for a re-man engine -- Your probably already passed that economic break point. You just need to decide what it's worth to you.
As for the age of the boat and what you'll spend for a re-man engine -- Your probably already passed that economic break point. You just need to decide what it's worth to you.
As for the bad cylinder he took it out and it ran well until it hit 4000 rpms then it lost power and stalled. He let it cool, restarted and it did the same thing when it hit 4000rpms. He said the piston is heating up and expanding in the cylinder. He said it runs good under 4000 but for how long who knows.
wanderer200
Well-Known Member
sfc2113
GreatGrady Captain
richie rich
Well-Known Member
If the piston is heating up and expanding in the cylinder to that extent it would seize the motor. To stall the motor, the rings would score the cylinder wall and it would be over......you'd see the smoke. The piston itself is smaller than the cylinder...the piston rings make up the difference......if the compression check is good and you are not blowing smoke, the rings are fine as well......you're probably losing power on top end or higher RPMs due to a fuel supply issue...carbs, injectors, fuel pump or fuel system...if it were getting that hot, you would also have the high temp alarm as well. A piece of aluminum doesn't just decide to "expand" more than it did 5 years ago. The cooling jacket around that specific cylinder wall would have to be cracked or plugged to do such a thing and not even give you a high temp alarm.
richie rich
Well-Known Member
If the piston were growing so much to the point of almost seizing the engine, the cylinder would be ruined and it would smoke like a chimney. If the rings or cylinder wall itself are that worn out to cause this low power and shut down issue, it will be noticeable....20-30psi minimum if not more.....but like I mentioned, it would really be smoking at this point.....did the guy do a compression test? If so, what did he find? The rings are what seal the cylinder from the cranckcase side....head gasket and valves seal from the topside.
If the head can come off, you can hand crank the engine until each cylinder hits bottom dead center and you can visually inspect the cylinder for wear marks, as well as measure the bore for wear. This is what I'd do before an all out expensive rebuild is done.
The fact that you can run under 4000 rpm without a power loss, smoke, overheating etc says volumes.......worn is worn...the engine will have blowby regardless if its that bad.
If the head can come off, you can hand crank the engine until each cylinder hits bottom dead center and you can visually inspect the cylinder for wear marks, as well as measure the bore for wear. This is what I'd do before an all out expensive rebuild is done.
The fact that you can run under 4000 rpm without a power loss, smoke, overheating etc says volumes.......worn is worn...the engine will have blowby regardless if its that bad.
ahill
Well-Known Member
Sounds like you have a "coking" problem. Carbon buildup freezes the bottom, intake, ring on the piston causing it to bind to the piston, lose compression and not draw in sufficient fuel/oil mixture causing the piston to overheat and score the cylinder walls and burn the the top of the piston. Common with older 2 strokes. I had 2 150's and rebuilt 1 twice and the other once even after using Chevron Techron and running engine tuner every 100 hrs.
You bring up very good points. I'm going to call my mechanic tomorrow and discuss this further. As far as the coking problem, if I were to de-carbon the engine what are the chances it would free up that ring?