1978 55HP Will Not Stop After Shift Forward.... Please help

[Khory Melynda Do]

Newly bought an older boat. Engine start up ok. misfire a couple times. after shift to forward, the engine went to high speed. I mean SCREAMING. Shifted back to neutral. propeler stop, but the engine is still screaming. I tried to turn off with the key it would not turn off, I have to put the chock on to stop the engine. it got real HOT. It happen a couple of time now. Please help. I am brand new at this. Thanks

 

[racerone]

OK were you running the motor in the water ? On a hose in the driveway ?---------Bought it from a dealer with warranty ?-----------------Pictures of the unit ? ------------Do linkages appear to move properly when you operate control box ( motor off and not running ) ?

 

[coueytwo]

Take the cowling (cover) off the motor and check the linkages like racerone said, you should see the gear shift come forward and the throttle come forward as you advance the lever.

 

[fishinwrench]

Broken throttle cable or sticky carb linkage.

And a fault in the kill circuit (blk/ wht wire in the harness) or a bad key switch.

 

[Khory Melynda Do]

Thanks all for replies.
Bought from Craigslist as is. I was running it in the drive way with hose. Took it out 2 times all seem fine. till 3 days ago. It will start and turn off fine till put in forward. Shifting, linkage to carb might be a little sticky, however it seem moving alright when moved back and fort with throttle cables everything seem to be in working order, as far as looking at the mechanics of the throttle cable to carb linkage.
I will look at the control box and check all cables next time as of now back to work and reality.
Though I do enjoy learning about the engine, and will enjoy it more when iam on the water. thanks again for all your help.
will post pic of the engine tomorrow

Broken throttle cable or sticky carb linkage.

And a fault in the kill circuit (blk/ wht wire in the harness) or a bad key switch.