No Spark

[SPORTZMASTER]

I've got an 85 Searay with a Mercruiser 140HP 3.0l. Boat ran great for 4 days in a row. Launched on the fifth day after a 10 hour tow and it would crank but not start. I've got fuel but no spark. Thought it was just a minor tune up so I replaced the plugs, cap, rotor, condensor and points. Still no spark. I have no spark from the coil but do have voltage at the + terminal so I thought the coil was bad. Replaced the coil, still no spark. Found this website and followed the diagnostics for points ignition system with no luck. I think I possibly have a ground issue. Can a bad shift interrupt switch cause a no spark issue. I'm sure I could take this in to the shop and have it fixed quickly but now it's a pride thing! Any advise would be great.

 

[Ryanhdd]

Re: No Spark

could be the solenoid.

 

[Thad]

Re: No Spark

This may sound crazy, but, is the gear shifter in neutral?

Do you have a kill switch lanyard?
Either of these two things will have you chasing a ghost.
It will not start in gear or if the lanyard is unhooked.
It will crank until you are out of battery, but never start.

 

[SPORTZMASTER]

Re: No Spark

Tested the starting system...seloniod, neutral safety switch, ignition switch, all are ok. It is in neutral and the shift interupt switch is in the W of the shift plate.

 

[searay3]

Re: No Spark

for testing only, remove the wires from the interupter. (without it you will have a very difficult time shifting out of gear in the water).

 

[littlebookworm]

Re: No Spark

Disconnect the tachometer lead at the coil. A bad tach could ground your ignition system. If that fixes the problem, you then have to check whether it's the tach itself or the wire leading to it from the coil. Do that by reconnecting the wire at the coil and disconnecting it from the back of the tach. If the engine starts, the tach is bad. If it doesn't, there is a ground short somewhere in the tach wire. Let us know what you find. Hy