Alrighty! First post on the forum! I am pretty new to the boat-owning world, but my family typically had one when I was growing up. I have a 1988 90 HP Mercury outboard (3 cylinders) on a 16' Checkmate Predictor. One of the previous owners removed the oil injection, so now it just runs on premix. I have two main problems with my outboard setup currently:
ISSUE NO. 1 - No Compression On One Cylinder
I'll start with some description of symptoms. It starts decently well, though I have a manual jumper switch currently connected to the starter solenoid, and it is sometimes stubborn to start on the water. When on the water, the boat takes a very very long time to get up to speed and get on plane, due to the fact that if I push the throttle down too fast, the engine just dies. I have to very incrementally give it more gas. I also sometimes cannot get on plane depending on how many people are in the boat or if I'm towing.
I checked compression on the cylinders a while back and I believe these were the results:
TOP: 90-100 psi
MIDDLE: 0 psi
BOTTOM: 90-100 psi
I might have the order mixed up on what cylinder had 0 psi, but this is my best recollection for now. When running the test on the 0 psi cylinder, it sounded noticeably different from the other cylinders.
I spoke with a repair shop in town and they said the slow acceleration issue I'm experiencing makes sense given the 0 psi on one of the cylinders. I am now in the process of trying to determine if it is worth my time and expense to repair the engine. In talking with some other people, they said it might be the reed valve on that cylinder that has gone bad or stuck open. However, the boat shop said if that's the case, I might get very low compression on all the cylinders because the air passage ways might be connected. Anyways, I thought I would seek some more advice from people more experienced with this specific engine before tearing things apart and examining. Could this be a reed valve issue? If reed valves are out of the question, is the issue likely more serious, such as a hole in a piston?
ISSUE NO. 2 - Throttle Lever
First off - if I should post this question in the Steering and Controls part of the forum, please tell me. I thought I would keep my questions together since the problems may in some way be related.
The last time I took the boat out, the throttle control lever became extremely loose and acted like it was not connected to anything. At one point, the boat was in gear and I could freely move the throttle lever forward and backward without affecting engine rpm at all. I had to kind of jam it to the side in a very particular spot for it to feel like it grabbed on something and then I could carefully get the boat to accelerate/decelerate or pull it out of gear. Any thoughts on what might be the problem and potential solution?
Thank you very much for any advice!
LJ
ISSUE NO. 1 - No Compression On One Cylinder
I'll start with some description of symptoms. It starts decently well, though I have a manual jumper switch currently connected to the starter solenoid, and it is sometimes stubborn to start on the water. When on the water, the boat takes a very very long time to get up to speed and get on plane, due to the fact that if I push the throttle down too fast, the engine just dies. I have to very incrementally give it more gas. I also sometimes cannot get on plane depending on how many people are in the boat or if I'm towing.
I checked compression on the cylinders a while back and I believe these were the results:
TOP: 90-100 psi
MIDDLE: 0 psi
BOTTOM: 90-100 psi
I might have the order mixed up on what cylinder had 0 psi, but this is my best recollection for now. When running the test on the 0 psi cylinder, it sounded noticeably different from the other cylinders.
I spoke with a repair shop in town and they said the slow acceleration issue I'm experiencing makes sense given the 0 psi on one of the cylinders. I am now in the process of trying to determine if it is worth my time and expense to repair the engine. In talking with some other people, they said it might be the reed valve on that cylinder that has gone bad or stuck open. However, the boat shop said if that's the case, I might get very low compression on all the cylinders because the air passage ways might be connected. Anyways, I thought I would seek some more advice from people more experienced with this specific engine before tearing things apart and examining. Could this be a reed valve issue? If reed valves are out of the question, is the issue likely more serious, such as a hole in a piston?
ISSUE NO. 2 - Throttle Lever
First off - if I should post this question in the Steering and Controls part of the forum, please tell me. I thought I would keep my questions together since the problems may in some way be related.
The last time I took the boat out, the throttle control lever became extremely loose and acted like it was not connected to anything. At one point, the boat was in gear and I could freely move the throttle lever forward and backward without affecting engine rpm at all. I had to kind of jam it to the side in a very particular spot for it to feel like it grabbed on something and then I could carefully get the boat to accelerate/decelerate or pull it out of gear. Any thoughts on what might be the problem and potential solution?
Thank you very much for any advice!
LJ
