1976 115 crossflow

[saltwatertaz]

Hi, my problem is a rattle that seems to be getting louder. A little history, I've had this motor for a few years, always ran great but seemed to have a little rattle. Coming back from fishing late one evening i was running about 5 grand trying to beat dark. Well the motor started to lose power and died. Tried to crank back up and it seemed to be seized. So a friend pulled me in. Went home and the next day tried turning over and it did fine. So I ran a compression check 120,121, 120,124. Same as id did when i got it,( first thing I did when i bought it). I have run the motor in the lake since, but not at full throttle. It seems the rattle maybe getting louder, could be my emagination. Is there a good check before tearing the block down for the rod bearing or wrist pins. Tell me what you think. Thanks

 

[Solittle]

Re: 1976 115 crossflow

Slow down just a tad before you start ripping it apart. Your description fits a classic overheating problem. When was the last time you replaced the water pump & t-stats??

Oh - - - - - and welcome!

 

[saltwatertaz]

Re: 1976 115 crossflow

thanks for the reply, I just this winter replaced the water pump and all the seals in the lower unit. I also added a telltale to this motor about two years ago to indicate I had water flowing. My intention is to add a pressure guage next. Thanks

 

[saltwatertaz]

Re: 1976 115 crossflow

Question, If it did shut down from overheating what damage did it do? I would have thought it would show up by a change in compression. Is there a electronic tempature sensor that I can add? Also where on the engine to place it. I think I will decarbon and at least add a pressure guage.

 

[F_R]

Re: 1976 115 crossflow

It already has an overheat warning horn in the remote control. To test it, look on the starboaard cylinder head for the sensor with a tan wire. Slide the insulator sleeve back, turn on the key and ground the sensor terminal to the head. Horn should blow. That tests the horn and wireing, but not the sensor itself. You just have to trust that part. Same as you do your car.

 

[Solittle]

Re: 1976 115 crossflow

And you replaced the t-stats when?

 

[saltwatertaz]

Re: 1976 115 crossflow

They were replaced three years ago. They seem to working properly, I have no problem with overheating at lower speeds. I idled to the back of a real stumpy slew saturday( took about 20 min. to get in) and it seemed fine.