1981 Merc 25 HP Problems

[Viper2872]

I just bought a boat that came with a 25 HP Mercury Outboard. It's in a little bit of rough shape. The previous owner used it without care what it looked like as long as it ran. I can't figure out how the tilt lock works. There was a broken plastic lever in the boat that I thought went to it but I don't know if/where it belongs. I have looked through diagrams to figure out how it works and have not had any success. I can manually push the latch that locks the motor down to get it to tilt but I thought there would be a lever to do this because it's very uncomfortable to reach around while doing this.

Also, the cowl is very loose and vibrates quite a bit. I think this is a gasket problem to the drive shaft housing. That is the only thing I can find that would be worn out to allow the cowl to vibrate.

 

[walleyehed]

Re: 1981 Merc 25 HP Problems

There are "T-LOCKS" on the front of the cowl with hooks. The Hook end needs to be screwed in on the threaded rod about 2 full turns to start with. You want just enough tension to add resistance to the over-center latch when you snap it over. You'll know if it's too much.

 

[Viper2872]

Re: 1981 Merc 25 HP Problems

I guess I should have been more clear. Its not just the top cowl that has the clip. Its the part of the cowl that clips to as well. The whole thing just rattles no matter how tight I have it clamped down.

When I took it out yesterday, I tried to throttle up, there was a clunking sound. As long as I kept it slow or out of gear, there was no clunking. As soon as I tried to put the boat on plane, that clunking was back. It almost seemed like it was only running on one cylinder, but it would idle just fine.

 

[Viper2872]

Re: 1981 Merc 25 HP Problems

I'm still curious as to why the motor was clunking or missing. I'm not sure which. If I run it out of the water, it revs up fine. If it is in the water, when I rev it up it clunks and shakes the whole boat like the prop is hitting rocks. I know its not because I was in 20ft of water.