96 Speedster Stbd Engine Dies at Idle Speed

[parkericharda]

I’ve read several posts on this topic but nothing is quite exactly what I’m experiencing.
My 96 Speedster will start up, both engines, I then run around, open throttle, no problem. Then when I bring the throttle back to idle speed, the stbd engine will just die. If I keep the throttle lever up a bit it stays running, otherwise dies. Then it’s almost impossible to start again... have to give it throttle while starting and sometimes I end up flooding it before I get it going again. I’ve changed the spark plugs, it’s not bad gas as it’s fine on the other engine. Carbs were rebuilt not too many hours ago and it is fine whenever there is throttle there. I’ve looked at the cable and seems to be moving just fine, not slipping or anything. Is there an idle speed adjust on these engines and if so where? Would something have just randomly slipped out of place? This engine also has a small water leak from a head bolt which I’ve tried to fix in the past. Still squirting water a bit. This engine has always struggled a bit when starting... like the battery is bad, but it’s not the battery. When the engine is warm, sometimes I am unable to reach full potential rpms. Always runs great at first startup. I can run 20-30 min at full throttle before having any issues. This engine also has problems revving to get you up on a plane (not sure what the extra rev is called but doesn’t work well on this engine like the other). I’ve had the issues for years, except for the stalling that’s new. So I’m not sure if this is a related issue or two separate issues going on. No one will work on these boats anymore and I’m not an awesome mechanic, so this is always challenging to figure out. I appreciate any advice.

 

[parkericharda]

Yesterday I took the boat out for some troubleshooting. I was unable to start up the Starboard engine at all now. It continues to turn over, but will not start. At times it seems like it's about to start, but then doesn't again. If I give it a little choke, then sometimes it backfires and a little smoke comes out of the air filter area. Someone suggested to me it may be the carbs but I'm not sure how to determine for sure if they need to be rebuilt. If that's the case, no-one wants to work on a 96 Sea Doo anymore, so...

 

[LikeabossTM]

If your engine is squirting water to the exterior of the head, is it just as likely that it's also squirting water into the cylinder(s) and having a hard time igniting the fuel/water mixture?

This seems like the first thing I'd check. Pull the head and inspect for damage/re-seal.

 

[parkericharda]

I took the carbs apart today. First time ever doing something like that. I was a little nervous, but found a great video on it someone made! One of the carbs had a little water residue, but the other one was MUCH worse. Obviously the water that's leading out of the head bolt (or maybe more than just that) is getting into the carbs and the hard water residue is just ruining the flow of gas. At least that's what I've deducted so far. Going to get a rebuild kit for both, and get them seals fixed, and the filter cleaned. I tried to clean everything as best I could, but thinking new seals will still be best. Will post the result.

 

[parkericharda]

I took off the head today on my stbd engine. The o-rings were completely disintegrated around one piston, and the other was on its way. Which is why there was also water in the pistons when I took it apart. Yikes! I suspect the o rings gone means that the engines are getting too hot. No temperature alarms, although sometimes this engine wouldn't turn over and it would do a single long beep - perhaps this means "I'm too hot" (checking the manual today on that). This engine has always had issues with water streaming well out the eyelet spout on this engine. Port engine is fine, but Stbd is less. Water does come out, but it is not a steady stream like the other engine does. I suspect that perhaps not enough water is flowing around the pistons, so it is getting hot, which caused the o rings to essentially melt. I do have a question, hoping someone can answer. There are little notches where the head bolt attaches to the piston housing which allows water to get to the head bolt. I'm not sure why they would manufacture it that way. Is it to keep the bolts from getting too hot? The thing is, hard water deposits sit there, and there is even a little rust around most if not all the head bolts. I've attached a photo so you can see the notches. Is the molycote supposed to protect that? Do I need more that usual of that when I put it back together? I don't have a shop manual so not sure how much I'm supposed to put and if it's on the threads only or the entire bolt. Thanks!

 

[parkericharda]

Completed rebuild and reinstall today. Engine runs great again! Only weird thing is that now when inserting the DESS key my short beeps are super quiet. Any idea why they suddenly are quiet?

 

[doni]

I have the same issue with my 97 speedster was it the carb, or the head that caused it to die? Its tough when no one works on these boats . I actually put a new rebuilt carb on it ,but same problem, maybe a bad rebuild i dont know.thanks doni