View Full Version : 4272 I think it is a spark issue?

08-08-2011, 10:41 PM
I need some advice. I have the p/n:4272 on a yamaha super jet. It appears that I have spark with no load and that is by grounding the plugs and turning over the motor. It idles fine when running, but bogs when you rev it up. One spark plug looks like it's new and wet looking as if there is no spark. (started with fresh plugs). It seems to me that there is a lack of spark when it's under load. Can this occur? What can i do to test it if possible?

Thanks in advance,


08-25-2011, 09:38 AM
Have you tried false triggering the ignition to see if both spark plugs are firing at the same time? The 4272 unit is a wasted spark system which means it will fire the spark plugs at the same time. If you still have a weak spark on one of the spark plugs it could be a bad coil please let me know which coil you have so I can get you the coil specs. Have you checked your battery to make sure itís supplying the proper amount of voltage to the unit?

Here is my email address to make it a little easier rcorral@msdpowersports.com

Thank you