Ended up working on the ’90 yesterday (Thursday). I put the new battery in it and it started up. It was pretty rough to get it started and from there it ran really rough. I actually had water hooked up to it and everything.
I had it run for a good 5 minutes at what I felt was idle and then started to rev it up. That’s where the issues started to happen. When it was reved up at higher speeds, it started to backfire through the carborator. My Dad and I decided that it was the rotary valve timing that was off, and needed to be timed correctly.
Now I’ve found two different ways for setting the timing. One way was the shop manual way and the other was found on the forums at stbonthweb.com. The forums guide pointed out not to do it the way the shop manual said. Seeing that I didn’t have a timing degree wheel, which is needed to do it the forums way, I tried to set it correctly according to the shop manual. After setting it the way the shop manual said, it was near impossible to get the jet ski to run. We did manage to get it running once, but it was running super rough and would not idle without dying.
I’m calling around to different jet ski locations today to find out if they have a timing degree wheel for sale. I’m going to try setting the rotary valve timing as the forums says this time. So far, the two places I’ve talked to said they need to order the part (which I would just do at stbontheweb.com for cheaper). I have one more place to try before I just order and wait.