93 90hp Force motor wont kill!

[balmfort]

Hello all - have an interesting problem. replaced the powerhead in a 1993 90hp Force. Powerhead came from 1990 motor. Finally have it all together and started it the other day, ran good on muffs. Problem is that it wont shut off when I turn the key off. Kill tether switch also doesn't make a difference. I've been researching on this forum for a few days to look for answers. I just replaced the ignition switch today with brand new one. didn't fix anything. again my motor starts and run fine, just wont shut off. The only way I can can kill the motor by jumping the post from the kill circuit on the switch box to ground.

It has Mercury Force ignition system with switch box type with posts, pn - 114-7778, How do I check to see if its the switch box? everything ran find when the boat stopped working.

 

[pnwboat]

You have a wiring or open ground connection problem. When you turn the ignition switch to the "OFF" position, it grounds out the Black/Yellow wire on the Switch Box. The ground connection is usually on the terminal strip on the side of the motor.

 

[balmfort]

thanks for the tip. I double checked all the wires and couldnt find a problem so I added some extra ground wires from the CDI mounting plate to the common ground on the block and it now works. I can kill the motor with the switch. Must have been some difference in the two blocks and the way the electrical system was grounded. Anyways thanks again. Now I can try to get it all tuned up and adjusted, just in time to put it away for the winter. :lol:
Fall is coming quickly here in Michigan.

 

[pnwboat]

There you go! Yes the ignition system mounting plate needs to be grounded to the engine block.