96 XP accelerate then dies(no bog)

[Brprxt215]

So back in October I purchased a 96 XP I’ve always wanted one! I checked compression it was 149-150 psi in both cylinders. Met the guy at the water to test it. Took a couple tries to get it to fire as it had not been ran in almost two years(not sure if it was properly winterized) it seemed to idol fine but when I would give it gas it would hesitate a couple of seconds then take off up to about 40mph then just cut out and die. Never once did I get it to stay running wide open. It did this about 5-6 times So I brought it back to shore and ended up buying it thinking it was some sort of fuel issue. I took it to a local shop told them the symptoms and they diagnosed it saying the crank was bad(said there is a lot of vibration in the bottom end.)(they only ran it on the trailer never the water)I have left it at the shop since October and they have not even touched it. So today I went and picked it up deciding rather then throwing $1-2,000 in labor cost I should just go through it myself. My question is do you guys believe the crank would be bad if it would actually start and move in the water or do you believe it is more likely a fuel issue maybe sucking air some where or carbs are gummed. Just looking for some direction. Thanks in advance for any advice!

 

[IDoSeaDoo]

Definitely sounds like a fueling issue. Crank problems come in two flavors: mechanical and oil-leak. Since there are two oil seals in the center of the crank, if they go out, they'll leak excess oil into one of the cylinders. This would cause excessive smoke and one of the plugs being oil fouled. The other issue a crank can have is bad bearings, which would be very obvious. You can feel it by turning the flywheel. It'll have excessive play or not be smooth when you turn it back/forth. If it starts and idles okay, it's likely neither of those problems. Sounds like it's starving for fuel. If you try to get it up to higher RPMs, does it backfire? This is a good indicator of a lean condition. Alternatively, it could be getting too much fuel at the higher throttle range, but unless someone turned the high speed screw waaaay out or put the wrong jet in there, it's highly unlikely. The usual culprit is grey tempo fuel lines (must be changed right away), the internal carb filter (most likely clogged if you have grey lines), clogged selector valve (personally have never witnessed this one), or an air leak somewhere, like the fuel/water separator. Also, try running it with the fuel cap off. Your vent could be clogged. When getting a new ski, it's always a good idea to rebuild the carbs. Be sure to use genuine Mikuni rebuild kits. Typically, guys reuse their pop-off springs, but the kit will come with new ones too if you want to change the pop-off pressure. Around 30psi is normal for that ski.

 

[Brprxt215]

i will check the plugs to see if they are oil fouled. I did not notice excessive smoke when I water tested it. When I get up to higher rpms is when it just dies out no backfire or anything revs up like it’s about to go full speed gets to about 40 and just dies. It does have replaced fuel lines as the grey ones are not in there. I’m not sure when the last time carbs were rebuilt but that was my plan is rebuild the carbs with the mikuni kit and replace the fuel lines again Incase there is something wrong with the ones on there. Then I will have peace of mind I know I did it. I will look into the tuning of the carbs as I bought a tdr water box and will need to adjust them to compensate for that. Sounds like I can rule out the crank issue which is a sigh of relief. Thanks for the information!

 

[mikidymac]

Don’t bother with the waterbox it won’t make any more power but will piss off everyone around you.