There is a member with cylinder blocks for sale now. It might be a good idea to look into as the symptoms you describe indicate rings and or cylinder bore damage. My first place to look would be water pump impeller. If the impeller is not known to be good , assume it needs to be checked and usually replaced. While it is possible in theory to bore cylinder to a standard oversize and fit oversize rings and pistons….The problem is oversized rings and pistons are hard to come by, You may be able to source a complete powerhead…that would get you back on water sooner. Lower crankshaft seal should be renewed even if all else looks good on a donor powerhead. I believe KE7,KF7, KG7 and KG4 powerhead will bolt right up. KE7 are common and I have seen then sell for $10.00 at swap meets. Not as much power, but, an option that can be swapped out when you have worked out issues with your present KF7 powerhead.
Those who KNOW are invited to chime in and correct me if I am in error or expand upon subject…Not often do Mercury fans suggest less power.
Louis
Remover INTAKE port covers to check pistons for scoring AND to push on rings with a probe to see if they are stuck in grooves or mover slightly when pressed. A very experienced friend fried a Mark 30 when water pump impeller failed at speed. He was too eager to try it out. It ran real well until it didn’t. He found block and parts to do a rebuild plus a new impeller. If you check impeller and find it has failed, take a look at piston and rings thru ports to confirm. Most likely the impeller failed and the powerhead seized up due to overheating. Not a big deal to rebuild the second one, but. all things done for the first time have a learning curve, thus my suggestion to look into a powerhead for now, Things go better when not under pressure.
The large plate on side of block is the EXHAUST manifold cover…NEVER attempt to remove without a good reason for doing so. One or more of the fasteners are stuck and will snap off, Assume all of the cover fasteners are stuck …use torch and gentle technique NOT force.
t
-
This reply was modified 4 years, 4 months ago by
.
-
This reply was modified 4 years, 4 months ago by
-
This reply was modified 4 years, 4 months ago by
