Freestyle MSD total loss playing up

J

JTI

Location
Australia
Hi,

I have an MSD total loss setup fitted to a Yamaha 701.

I was having a problem with it where it breaks down to one cylinder after about 20 minutes. Before then it ran great. I narrowed it down to the rear cylinder. I tested all the system, and i came up with one of the pick ups had an open circuit. It was on the cylinder (rear) that was having the problem, so i replaced the pick up thinking i would be good to go again.

I was wrong.

Ski ran good for about 45 mins this time, then was cutting out, just like hitting the stop button, and would start straight back up again, then after about 15 mins more it dropped to one cylinder and would not come back. So it got towed home.
It would still only run on 1 cylinder in the shed, so I tested every piece of wiring on the MSD that i could think of doing ohms readings to see if i had a break. Came up with nothing. Both coils test that they are getting grounded. Both pickups are testing fine. Battery amps and voltage are fine.

I then switched the MSD to test mode and spun the crank slowly to see if i was getting contact with the pickups, which i am.
I also bridged the pick up wires to the coil and got both of the coil packs to spark fine.

I put it all back together as i could not find anything wrong, started it and its running on 2 cylinders now. I know that if i take it back out on the water, it is going to play up again as i have not changed anything.

My only thought is that it is running on 2 cylinders now seen i disconnected 12V from the brain, which would have reset the MSD. Am i correct?

Any one with MSD total loss knowledge, that might be able to shed some light on this would be much appreciated. I have emailed the MSD tech line, but no response.
 
fast superjet chase

fast superjet chase

Location
Colorado
Well still could be a coil dropping out on you. Even a bad coil can still test good. And we have also had the brain go bad acting the same way as yours. Not saying that's the problem. And always add extra grounds to the brain the like there grounds.
 
J

JTI

Location
Australia
I have swapped the coils over. I done this last time which is how I narrowed down the pick up issue. I swapped the coils and the problem stayed on the rear cylinder, so I tested the pick up and this is were I found a problem. So I swapped it out with a new one. But it hasn't fixed the problem.
 
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Pablo

Pablo

sqeez bth levrs & lean bk
Site Supporter
Location
georgia
Not to be Debbie Downer here, but ill bet 2:1 its ur brain. I've had brains that were going bad act like that...fine on the trailer but after a few mins in the water getting it hot it starts cutting out on one channel. I swapped pickups and coils individually until i narrowed it to the brain. Is it a 2 or 3 channel brain. If u can switch from the problem channel to the spare channel that's the quickest diagnosis. U could send the brain to JSS but that'll take some time. Summit sells brains reasonably. If u buy a new one make sure u get a 3 channel for just this scenario. Good luck hombre.
 
J

JTI

Location
Australia
That is what I'm thinking as I have checked everything else I can think of.
It is a 3 channel brain. Is it as simple as connecting the green pick up on the bad cylinder (No2 Brown wires) to the 3rd channel (orange wires) or is there more to it than that?
 
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