Shift Interrupt Switch?

[redneck joe]

New Delco ignition system, plug wires, batteries, lots of stuff. New carb on. Runs great, unless....


Not getting spark at the plug cap or the distributor. My buddy put his meter on the interrupter switch and got nothing 'on the back side' I had a thought and shifted in and out of gear a few times, fired right up. Forgot to re-check the 'back side' of the switch but does this sound like it is going bad?

 

[Rick Stephens]

The instructions for installing the Delco EST usually mean switching the backside of the interrupt switch from a ground to a purple hot wire source. Did you do the installation that way?

 

[redneck joe]

i paid for it to be done when I was travelling. Would it cause intermittent issues?

 

[Rick Stephens]

No idea, never run an EST that wasn't wired properly. Check it though, make sure they did it right. They have to disconnect the backside of the interrupt switch from ground and attach to power. If done wrong, I don't know what happens if the EST module is grounded instead of powered to break the ignition and get out of gear.

The other possible issue is a bad lower shift cable. Have someone move your shift lever. If the engine is not running and is not in the water, the interrupt switch should never move at all. If it doe move, sitting in the driveway, your lower cable is sticking.

 

[bruceb58]

Jumper around the interrupt switch to make it have constant 12V to see if that helps. You just won't be able to shift it out of gear so do it in the middle of the water somewhere.

It wouldn't even run if ground was supplied to that line.

 

[redneck joe]

No idea, never run an EST that wasn't wired properly. Check it though, make sure they did it right. They have to disconnect the backside of the interrupt switch from ground and attach to power. If done wrong, I don't know what happens if the EST module is grounded instead of powered to break the ignition and get out of gear.

The other possible issue is a bad lower shift cable. Have someone move your shift lever. If the engine is not running and is not in the water, the interrupt switch should never move at all. If it doe move, sitting in the driveway, your lower cable is sticking.

Ok, I would think the latter as bruce mentioned I would think it wouldn't run at all if wired incorrectly. But I hope you all have figured out by now I'm not the expert on any of this I just like to try myself first then if I take to a mechanic be able to speak intelligently about what is happening and his repairs completed.


If I said that it is stiff going into neutral from both forward and reverse indicate anything? It has always been that way since I've owned it, LU been pulled several times by several people, I've shocked the sh.. out of myself on the interrupter once (only once) when jacking around a few seasons ago so believe that should be ok at least then. The no spark issue is recent nice the new electronics put on.

 

[Bt Doctur]

go to the shift interupter switch and remove the green/white wire , see if it now runs. If Yes, its wired to ground and not 12v

 

[redneck joe]

it did run, when i pumped back and forth a few times with nothing other than that done.

 

[redneck joe]

The other possible issue is a bad lower shift cable. Have someone move your shift lever. If the engine is not running and is not in the water, the interrupt switch should never move at all. If it doe move, sitting in the driveway, your lower cable is sticking.

Boom. Putting on the fall go to sleep list.

 

[achris]

Careful shifting with the engine not running. If the shift dog is in the wrong placeit will force the switch and possible alter the cable adjustment. If you must shift with the engine not running, have someone turn the propeller as you do, in the opposite direction. If you're shifting to forward have them turn the prop in reverse.

Chris. ...