Johnson 1970 115 hp will not shut down

[Livetofluke]

I recently bought an early 70s 17' boat with a 115hp Johnson 1970 with electric shift. First it wouldn't start at all, then after reading the other posts I narrowed it down to the pack. I replaced the coil and the pack now it seems to run well and start consistently but won't shut down unles I disconect the cable at the battery. I thought it might be the switch so I replaced the switch but still doesn't shut off without disconnecting the battery. The odd part is that there is a black wire in the cable from the engine to the controll box that appears to be a ground. This wire was attached to the old switch to what appears to be a dead spot(old switch appears to have been replaced). the strange part is that the black wire does not appear on the wiring diagram in the seloc manual. thanks or your time Greg.

 

[phatmanmike]

Re: Johnson 1970 115 hp will not shut down

black wires in the switch are usually ground wires, that when the key is turned off, it grounds out the ignition , there by killing the motor

 

[ledgefinder]

Re: Johnson 1970 115 hp will not shut down

The 1969-72 V4s' ignitions run off 12V from the battery. To switch them off, the 12V is no longer applied to the CD box (pack). This is different from the 1973 and newer V4s, whose ignitions are self-energized and are killed by grounding the black/yellow wire.<br /><br />So, you need to see where the 12V to your CD box is coming from, then it should be obvious why it doesn't stop. Does that black wire show 12V+? Someone might have 'hot-wired' the boat with whatever color wire was handy. <br /><br />My understanding is that it's unwise to disconnect the battery from those motors while they're running. The original CD boxes are pretty delicate, and don't like 'dirty' voltage (voltage with big spikes/transients). Your new one may be more robust, but still risky...

 

[captain spike]

Re: Johnson 1970 115 hp will not shut down

be carefull,those power packs are big$$$$take your time and read your manuel its worth it!<br /><br /> *** 1971 18'winner 1969 115 jony ob ***

 

[ddaigle]

Re: Johnson 1970 115 hp will not shut down

Had the same problem with my 71 60 horse. The electric shift motors have a shift diode( looks like a plastic covered peanut on motor)that keeps the motor from going into gear when you shut it off and lurching the boat forward. When these go bad the motor will not turn off with the key as the bad diode still supplies power to amp. You can run it without the diode or its an easy replace.

 

[ddaigle]

Re: Johnson 1970 115 hp will not shut down

Had the same problem with my 71 60 horse. The electric shift motors have a shift diode( looks like a plastic covered peanut on motor)that keeps the motor from going into gear when you shut it off and lurching the boat forward. When these go bad the motor will not turn off with the key as the bad diode still supplies power to amp. You can run it without the diode or its an easy replace.

 

[Livetofluke]

Re: Johnson 1970 115 hp will not shut down

Thanks for the fast response. I haven't got to the boat to continue work but I have a few ideas about where to start. I'm going to check the diodes and ignition safety switch next.