You'd have to find someone that has experience doing it that way first, and then ask them.Originally Posted by jarhead175
You'll only need I take and head gaskets and some shop supplies and a set of rings, but I wouldn't let someone that's never done it before that way do it.
Make sure the engine was run on the water, UNDER LOAD, at planing RPM's for at least 5 minutes before compression was retested. This is important- Power Tune can LOOSEN the carbon, but relies on the operation of the engine to REMOVE the carbon.
After it's been run under load, ON THE WATER, I would repeat the compression test starting at the BOTTOM and working UP.
Make sure test is done exactly as described here:
Compression Testing
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
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Picked the boat back up from the shop. They ran a gallon of their secret stuff threw the motor. So now the motor has been decarbed every cylinder came up 5psi but the bottom left is still down (5@115 -1@95). Guess my next step is to try to find someone that will hone and replace the piston/rings in one cylinder which I am finding out is not easy to do. I have talked to four techs in the Tulsa area and they won't touch it unless it's a complete rebuild at $4,000+.
Wow, I misread you first post; I thought you said one cylinder only had 20psi compression, lol.
The cylinder at 95psi isnt horrible imo. Did compression of the low cylinder improve at all after the "special sauce".
If it were me...I wouldn't be freaking out at this point, and be ready to spend big bucks because of the low psi cylinder. I would decarb again....bottle of seafoam mixed with a gallon of pre-mix gas. Then launch the boat and run the snot out of it(hooked back up to the boat's fuel tank, of course) for 30mins to clear the loosened carbon out of the motor.
Then re-test compression. If compression has improved ...run motor again on the water to possibly further free the ring(and/or remove more carbon).
If no appreciable improvement is made...then replace the head gasket. If still no improvement after new gasket...then find a shop to re-ring.
JMO
1999 Stratos 273 / '98 Johnson 150hp
Do a leakdown and find out where your compression is going.
2001 Mercury Optimax 225
0T344965
2000 Mercury ELPTO 125
0T072885
Guessing it needs to go back to the shop for a leakdown?
All the cylinders came up 5psi even the weak one it was at 90psi before and 95psi after.
You have a PM
+1 This will provide you with the info you need to know
A leakdown test is smart, after a good decarb. But I think you (or a mechanic) will need to pull the head to check the cylinder and the gasket to see the real problem. That should be the next step.
Mercury 2002 200hp Carbed Saltwater
OT566776
2002 Cape Horn 22' Bay
Had a mechanic put a bore scope in it and he said their is light scaring on the cylinder wall that can be honed out. He said it is eating the ring and when the piston hits the wall it's over. But I can not find a shop that will rework one cylinder. I asked them all if they can hone all six, put new rings in all six, and a new piston in the low one. All I get told is they will not do anything less then a complete rebuild.
Last edited by jarhead175; 05-25-2017 at 02:26 PM.
Probably all about liability and reputation. If they do the quick method you want and it grenades soon after they worked on it, guess who gets the blame? Not worth the risk for them.
I kind of understand why they won't but at the same time a new piston and new rings in a honed out motor should last as long or longer then the original as long as the reason that it failed in the first place is addressed.
I have found very few shop actually rebuild motors. They quote you a price to rebuild then order a reman from mercury and replace the powerhead. That way all the liability is on mercury if their is a issue with the rebuild. I understand why they do it from a liability stand point but still feel it is kinda shady.
Anyway I have decided what I am going to do. It's going to set for a few weeks then be rebuilt by a reputable motor man in Texas. Talked to the money lady lastnight and got approved.
i would call jay smith racing engines,i think he is in texas and have him rebuild it before it goes boom, i am guessing around 3500-4000 if the boat is worth a rebuilt motor but i would stop running it good luck
Yes he is in Texas, $4,500, and I talked to him yesterday
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