84 Merc 115 I6 thunderbolt reverse problems

[iraqarmyvet]

when I put the unit into reverse it grinds a bit like its not locking in. It does back up very slow. is that just cable adjustment. also when putting it in forward it shifts very hard, loud clunk.

I have to replace the fuel line and possibly the fuel cap, the tank expands and does not release the pressure.


I just got this boat and trying to go thru it before it hits the water.

Thanks

 

[daveswaves]

Re: 84 Merc 115 I6 thunderbolt reverse problems

when I put the unit into reverse it grinds a bit like its not locking in. It does back up very slow. is that just cable adjustment. also when putting it in forward it shifts very hard, loud clunk.

I have to replace the fuel line and possibly the fuel cap, the tank expands and does not release the pressure.


I just got this boat and trying to go thru it before it hits the water.

Thanks

Reverse is always slow due to the shape of the boat, flat at the back, more drag. Plus the prop is designed to push water, not pull it.
The grinding could be cable adjustment or your idle could be too high. 800 rpm or lower in neutral is best. The reverse clutch dog has a tendency to wear and cause the same problem as well. The only way to tell if it is that is to dissassemble the lower unit. Check the other stuff first. Since it clunks going into forward I suspect the idle is too high.