Power to coil packs

[Chris Sadler]

I had an motor that lost power and found compression in #4 was way low. After trying several things to improve the performance with help from SBT tech support the problem just got worse and eventually the motor just died. It was sent back and a new one delivered under the awesome warranty program. I installed it with no issues. Upon trying to fire it up I could not get it to fire. I found the issue to be that I am not getting power to the #1 and #4 coil pack. I first noticed this when checking the fuel injectors. Found the #1 and #4 injectors not squirting as well as no spark from #1 and #4 plugs when grounding to valve cover bolt. #2 and #3 plugs and injectors seem to work fine. When I switch the wiring connections to the coil packs #'s 2 and 3 don't work but #'s 1 and 4 do. So, I checked the two wires from the connector at the coil pack back to the computer and they sound out using the multimeter, so they should be fine. So, I guess my question is...before I replace the computer, is there anything else such as a sensor, timing, etc. that could cause this issue? I am wondering if this problem is what caused the #4 cylinder to run too lean and burn up (piston burnt and shattered with the old motor. Any help would be appreciated.

[Technical Support]

Re: Power to coil packs

Chris there are a ton of issues with the computers failing and dumping raw fuel into the cylinders on Yamaha 4 strokes so yep issues with the computers are known. We have seen many issues with wire harness problems on any thing from 02-2011 skis too so double check anything you can wire harness wise 1st then resort to the computer.