G
Grapevine
Guest
"I have a 1988 25HP Mercury lo
"I have a 1988 25HP Mercury long shaft, tiller control outboard that has been very good to me over the six or so years that I have owned it. It has seen only freshwater use. When I purchased the motor, the compression figures were identical in the top and bottom cylinders. Recently, I checked compression and discovered that I currently have about 118 psi in the top cylinder and about 122 psi in the bottom cylinder. The motor still runs great. My questions are as follows:
Is a 4 pound variance a sign of big trouble in the near future?
If not a sign of big trouble, can I expect to get another 10 years out of this motor with regular maintenance? In other words, am I crazy to drop a few bucks on parts and labor for a waterpump impeller (an every few years item for me) and lower unit seals (since she is almost 20 years old) for this motor or will this motor likely live to see that pay off.
Should I be afraid to run this motor at wide open throttle. In the past, I heard that running an outboard at WOT for more than a few seconds to get the boat on plane is like asking for a powerhead failure. As a result, I am very careful not to run this motor at more than about 3/4 throttle. I've recently heard differing opinions on this. What's the truth?
What is the reliability record of this engine compared to other outboards (ie bigger 3-6 cylinder motors and small OMC outboards)? Are the smaller motors generally more reliable?
Thanks for taking the time to address my curiosities!"
"I have a 1988 25HP Mercury long shaft, tiller control outboard that has been very good to me over the six or so years that I have owned it. It has seen only freshwater use. When I purchased the motor, the compression figures were identical in the top and bottom cylinders. Recently, I checked compression and discovered that I currently have about 118 psi in the top cylinder and about 122 psi in the bottom cylinder. The motor still runs great. My questions are as follows:
Is a 4 pound variance a sign of big trouble in the near future?
If not a sign of big trouble, can I expect to get another 10 years out of this motor with regular maintenance? In other words, am I crazy to drop a few bucks on parts and labor for a waterpump impeller (an every few years item for me) and lower unit seals (since she is almost 20 years old) for this motor or will this motor likely live to see that pay off.
Should I be afraid to run this motor at wide open throttle. In the past, I heard that running an outboard at WOT for more than a few seconds to get the boat on plane is like asking for a powerhead failure. As a result, I am very careful not to run this motor at more than about 3/4 throttle. I've recently heard differing opinions on this. What's the truth?
What is the reliability record of this engine compared to other outboards (ie bigger 3-6 cylinder motors and small OMC outboards)? Are the smaller motors generally more reliable?
Thanks for taking the time to address my curiosities!"
