'71 Starcraft 21'. I/0 Merc. Spark interrupter switch???

[Doboy]

Hi. The old girl has been sitting for a while. Time to pull her out, fire her up & see if the G-kids want to learn to tube & ski.
Dumped some gas down her throat 2-3 times, & she fired up & purred like brand new!
I had the lower unit in a drum of water, along the head phones on. After she warmed up I shifted into forward,, no problems. Back into neutral, then into reverse slowly,
SHE DIED!
Back into neutral & Crank crank crank. Dumped more gas in her just to see, & nothing.
NO SPARK. I think the plunger on the spark interrupter switch stuck????
Is that possible? Everything on the transom seems to be functioning properly.
Or, maybe the contacts on the inside of that switch are corroded?
Shouldn't those switches be totally water proof?

And lastly,,, would I be able to run a hot jumper wire from the battery to the positive side of the coil, & fire her up?
Where would I find that part number, & or replacement switch?

THANKS tons for any guidance!

 

[kenny nunez]

Your problem is in the upper gear housing where the shift slider travels for reverse. The switch is not the problem. There is a build up of crud in that area preventing the slider with just enough resistance to activate the switch. Jumping a wire from the battery will not help and end up burning the points up.
You might luck out by disconnecting the short cable that goes to the transom and with the engine running with a flush out try pulling and pushing the cable from forward to reverse which might clear the resistance.
If this does not work you will have to pull the drive to clean out the crud.
There are tutorials on this site to guide you through the repair.