1993 Yamaha 85HP issues

nathansr06

Cadet
Joined
Mar 30, 2014
Messages
15
So, I purchased a new boat. A 1993 Skeeter SS90 with a 1993 Yamaha 85 HP (C85TLRR engine model). Family owned boat, I am the 2nd owner. I went through it some before taking it out on the water as it has not been on the water in some years. Water pump was changed last year and functions properly(water coming from the telltail). Started right up after some fresh fuel.
Took it out on the water today, starts and sound great(runs smooth). When you shift to reverse, you can feel it make it into reverse but it grind pretty bad and it reverses slow as if you give it any more gas than just putting it in gear it revs but doesnt speed up in reverse. It just grinds... I was hoping the cable just needed to be adjusted but I'm thinking not.
2nd problem. After cruising at WOT and then slowing down to a trolling speed for a few minutes the alarm went off on the control box. I killed it and took the cowl off. It wasnt got and I could touch the engine with my bare hand without getting burned. Bad thermostat or some kind of sensor?
3rd problem. After cruising across the lake and after the alarm went off that one time we were cruising at WOT and then it just kinda slowed down. Went from 32MPH to about 5 and the engine stayed about 2k RPM(while still at full throttle). Killed it for a minute or so and then it was fine again after that. Ran WOT back to the boat ramp and loaded up as I didnt want to have to paddle in.

sorry for the long post, you guys have helped me out a ton before and I'm hoping yall can again!! Any help would be appreciated!
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
For problem #1, I would change the gear oil in the lower unit and check for metal shavings in the drained oil.

For #2 and #3, I would focus on the thermo switch. You can replace it or buy the service manual, which will tell you how to test it.
 

nathansr06

Cadet
Joined
Mar 30, 2014
Messages
15
Well, yesterday we pulled the lower unit and pulled the gear assembly and driveshaft. The problem was the shift shaft was a notch or two off and the shift cam was not engaging reverse fully. Took a little time and figuring out but took it out today and it worked like a charm. We went out on the lake and did some cruising and fishing and everything worked great. The only issue now is once its warmed up but not everytime when you out it in gear it stalls out. Have to give it a little gas and put it into gear or it will just keep stalling out. Any ideas? Other than that I think we got her lined out. First time on the water in ten years!
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
Nice find in the lower unit.

For the stalling, I would check for air leaks around the intake. Too much air going in might explain why it stalls and you have to give it gas to get it to start. Maybe one of the carburetor caps is missing, or there's a leak in the air cleaner gasket.
 

nathansr06

Cadet
Joined
Mar 30, 2014
Messages
15
I took off the carbs and got them cleaned up. Went back out on the water and it did the same thing. Idled fine, took off good and then bogged down. After a few minutes of head scratching I started from the beginning of the fuel system. Got to the fuel quick connect where it goes into the engine. The O-ring was messed up. I got it straightened back out in the fitting and it ran great again. Spent the rest of the afternoon on the lake with no more issues. Can I just switch that fitting out with a hose barb and do away with the quick connect. I have no use for the quick connect as i dont have a removable tank.
 
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