95 SLT 750 Engine RPM changes

[neal233]

My ski starts OK. When I give it full throttle it accellerates to max RPM, then in about 30 seconds the RPM cuts in half when still holding full throttle. Then after 30 seconds it will pick uo again. This repeats it self and sometimes it stays at half RPM's with throttle full on.

This is what I have checked thus far

Resistance from spark plug boot to ground is 8.3K ohms
Resistance from wire end to ground is 3.4K ohms
Exposed plug wire end and found very weak spark from wire to ground. Spark will not jump even a 1/8 in gap

Will a weak spark cause the above eratic RPM condition??

What's most likely cause for the weak spark??

[rob2337]

I have the same problem. Machine will be cruising at wot, then drops to 5000rpm. Then sometimes it goes back up to full throttle, sometimes stays.

I am convinced that I am losing a spark on one of the cylinders when it happens.

I haven't finished trouble shooting the problem. It was suggested that I cut back 1/8" from each spark plug wire, then reattach the boots.

Let me know if you find anything else.

[xlint89]

Neal, if you have weak spark, try ohm testing the coils and elec stator. The test and measurements are in the tech section manuals.

[neal233]

I put a full charge on the battery
Cut back 1/4 in on each plug wire
Removed the "critical" ground screw in the elect box, cleaned all 3 wires and the metal clip that holds stuff in place with MEK and sand paper, screwed it all tight.
Problem seems to be solved

[Yota_Junkie]

which three wires??? And what screw?? I am new to these skis.

[xlint89]

I put a full charge on the battery
Cut back 1/4 in on each plug wire
Removed the "critical" ground screw in the elect box, cleaned all 3 wires and the metal clip that holds stuff in place with MEK and sand paper, screwed it all tight.
Problem seems to be solved

Thanks for the follow up Neal.

Yota, the grounds are inside the black elec box. And the ground at the engine plate for the battery cable.

[neal233]

Thanks

By the way I also re-gaped the spark plugs to .026