40hp BIGTWIN shifting problem (mid 60s)

[Logansdaddy]

This thing is attached to a 1964 Starcraft and runs great even though it sat in a hangar for years. Only problem is when I shift into forward gear, the motor jumps up out of the water and drops into neutral. The vibration on the handle is too much for me to hold in fwd gear and the boat takes on too much water trying to get back to the dock in reverse.

I've had people tell me several different things but nothing seems to work. Water pump has been replaced. Got boat, motor, and trailer for $300 several years ago and haven't been able to enjoy it since!

Hate to admit I'm not exactly mechanically inclined so any help y'all can give would be much appreciated before fishing opener May1st!!!

 

[stevenj]

Re: 40hp BIGTWIN shifting problem (mid 60s)

something does not sound right. An outboard in forward gear puts all its energy into trying to push the motor thru the transom and thru your boat.

By your description this is not an electric shift correct?

 

[steelespike]

Re: 40hp BIGTWIN shifting problem (mid 60s)

Model number off the plate on top of the mounting bracket would help.
Have you tried to disconnect the remote shift cable and shift by hand?
Kicking out of the water when shifting to forward doesn't make sense.
It appears it is going into reverse and slipping back to neutral.
The idle should be as low as possible about 700 rpm.
My guess is something is wrong in the gearcase.(where the prop shaft comes out of)For the mechanically inclined a simple assembly.I don't think its for you.
Perhaps a friend can help but find a service manual first.Sometimes you can find them at the library.

 

[tashasdaddy]

Re: 40hp BIGTWIN shifting problem (mid 60s)

well it could be several things, 1 shift linkage not properly connected, not going all the way in gear. 2 clutch dog, and forward gear worn out. 3 misadjusted cable.