Quick Intro: I am an amateur outboard mechanic with the hobby of buying older stuff and cleaning up for the enjoyment and then selling to fun my next purchase. By no means am I a seasoned mechanic but I am have some experience and am an engineer by trade.
Background for this project: I recently purchased a rig with a 1985 xd25 Mercury outboard. I have verified the year with serial number lookup. When testing the motor I found that it will pop out of forward gear in the following cases. 1. When I open the throttle quickly from a stop 2. When I reach a certain RPM. These are both very consistent to reproduce. Reverse is not problem.
What I have done about it: I dropped the lower unit and pulled the gearbox apart. I can see that there is wear on the corners of the dog and the inside of the forward gear where the dog and the gear meet. I purchased a 1987 25XD as a parts motor. I dropped the gearbox and pulled everything out. The dog and the forward gears were slightly worn but in much better shape than the originals that I pulled. I put the used parts into my original gearbox and headed out to test.
Test results: To my dismay the used parts have not addressed the problem. The thing will still pop out of gear same as with original configuration. Hmmm
Question: Could it be something besides worn gear surfaces?
I am hesitant to buy a new gear due the concern that I would be in the same situation. I’ll take pics of the dog and forward gear for the original lower unit and the newer ones that I replaced with. I’m stumped because while the gears show wear, it is quite minimal, especially with the newer replacements and yet I’m still seeing the same issue.
I’m hoping for some advice about other possible root causes for the thing popping out of gear and suggestions for moving forward with diagnosis. Also the larger overall question which is should I throw any more $$$ into the project or just move on. A new gear and dog run about $500 and the motor itself is worth about that much.
BTW I spent $200 on the used parts motor so I'm already in for that much.
Thought and opinions appreciated.
Best,
Bob
Background for this project: I recently purchased a rig with a 1985 xd25 Mercury outboard. I have verified the year with serial number lookup. When testing the motor I found that it will pop out of forward gear in the following cases. 1. When I open the throttle quickly from a stop 2. When I reach a certain RPM. These are both very consistent to reproduce. Reverse is not problem.
What I have done about it: I dropped the lower unit and pulled the gearbox apart. I can see that there is wear on the corners of the dog and the inside of the forward gear where the dog and the gear meet. I purchased a 1987 25XD as a parts motor. I dropped the gearbox and pulled everything out. The dog and the forward gears were slightly worn but in much better shape than the originals that I pulled. I put the used parts into my original gearbox and headed out to test.
Test results: To my dismay the used parts have not addressed the problem. The thing will still pop out of gear same as with original configuration. Hmmm
Question: Could it be something besides worn gear surfaces?
I am hesitant to buy a new gear due the concern that I would be in the same situation. I’ll take pics of the dog and forward gear for the original lower unit and the newer ones that I replaced with. I’m stumped because while the gears show wear, it is quite minimal, especially with the newer replacements and yet I’m still seeing the same issue.
I’m hoping for some advice about other possible root causes for the thing popping out of gear and suggestions for moving forward with diagnosis. Also the larger overall question which is should I throw any more $$$ into the project or just move on. A new gear and dog run about $500 and the motor itself is worth about that much.
BTW I spent $200 on the used parts motor so I'm already in for that much.
Thought and opinions appreciated.
Best,
Bob
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