1996 waveraider 760 quit firing need your opinion to troubleshoot

[RandyJ]

This waveraider had been sitting up several years. I did a thorough cleaning of the fuel system, new primer, rebuilt carbs, completely cleaned tank, new fuel filter, new lines after filter. Relatively easy to get it started and it ran fine out of water. Someone had disconnected the kill switch wires. I couldn't shut it off so I turned off the fuel. Immediately after that I noticed that I had failed to connect the pulse line on the rear carburetor. As I reached to connect it the engine suddenly stopped running as if the kill switch was depressed. Several times I tried to start it. I removed the spark plugs connected the spark plug wires and grounded them to the engine. When I did this with my hand I got a bit of a shock. When I used a piece of pvc pipe to hold them tight to the head bolts for a good ground there was no spark at the spark plugs.
Does anyone have a procedure to diagnose if it is a bad igniter (ECU or whatever you want to call it)? Any other suggestions of what could be the problem. Faulty connections? Short or grounding issues? I want to diagnose, not just throw parts at it.

[john zigler]

Re: 1996 waveraider 760 quit firing need your opinion to troubleshoot

Yamaha Start/stop switches are a common problem, and can cause a no spark condition.

Did you plug the stop wires back in? If so that may be your problem.

I unplug BOTH plugs. Start, and stop. Start wires are red/brown. Stop are white/black. With both plugs unplugged from the switch, I then jump start the red/brown wires. You can use a paper clip to do this. The engine will crank, and then check for spark. Be aware, it MAY start. if it does, just plug the black/white wires in quick, and hit the stop button. (It may just kill as soon as you plug the white/black wire plug in).

If you do all this and you still don't have spark, you have a different issue, and need to start testing other components. (Ignition coil, Stator coil and CDI). I strongly recommend getting a shop manual for your ski which will have test procedures, and values.

[RandyJ]

Re: 1996 waveraider 760 quit firing need your opinion to troubleshoot

Thanks. This thing is baffling me. It was not firing but had voltage to the coil. I put in a new coil and now it is getting fire but not hitting at all... as if it is flooded or no fire. Everything seems to check out... getting fuel (I even use starting fluid). Good compression. and now it is getting fire.... just absolutely will not start. I cleaned the complete fuel system. It had sat for about a year. I cleaned the carburetors and installed them. It ran great for a few minutes and a few starts... then it quit firing and wouldn't hit. I let it set several months before getting back to it. I didn't do anything other than clean the tank and fuel lines then made sure the primer pump and lines are good. I put a battery in it then it started right up like new! It rained for a couple of days then I went out and attempted to start again... NOTHING! This is when I went into "the box" to check for voltage to the coil... it was good but no fire.... Now, with a new coil I get fire but NOTHING when I try to start it. Cranking speed is fine. It doesn't sound like it is firing but when I pulled the plugs to check it was getting plenty of nice blue fire. Sparkplugs were wet so I know it is getting fuel.