Hello everyone, I am new to the forum, as well as new to jetskis as well. I bought a 97 gsi a couple of weeks ago. The ski is a little rough, but the owner said it ran a couple of years ago. I tore into it and changed the fuel lines, new oil filter, new battery, etc. I also ordered the mikuni carb rebuild kit and rebuilt the carb. As of yesterday it turns over and idles. I messed with tuning up the carb and it idles pretty well. When you rev on the throttle there is some major backfire right away. After a few minutes of trying to rev a little more it eventually dies. I googled some about the air/fuel mixture and worked with that some and still nothing. I feel like I am missing something simple, or possibly there is something I skipped over. I am very new to this, and any help or guidance or anything would be very appreciated as I am getting real eager to try and put this thing in the water. Thank you in advance! Any help is appreciated!
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97 GSI Backfiring please help!
- Thread starter Dschall3
- Start date
2 things I would check are 1. The voltage regulator, test the volts of your battery at rest, should be around 12.5 to 12.8 volts, start the ski and at idle note the DC volts at the battery , they should be roughly 13.5 ish at idle, rev it up to 4500 rpm and the volts should go to roughly 14 volts. If they don’t go up at 4500 rpm or they go really high or really low then you need a voltage regulator/rectifier. 2. The rotary valve being out of time could be causing your backfiring poor running issue’s, I’ve never timed the rotary valve but there are lots of videos on you tube and you should be able to find the specs in your shop manual,
Also, is it backfiring out of the carb or out of the exhaust? Where did you get the rebuild kit from? Set the high and lows to da Tory settings? Did you check the pop off and che k to see if the needle and or seat is leaking? Check after the carb is back together to see if the needle is being held open? That can cause backfiring out the exhaust. Mikidymac has a great carb rebuild thread, if you follow it, you can rule out any carb issues.
