97 xp starts fine cold hard to start hot

[Banana Yellow]

Newby here. Just bought 97 xp about 4 months ago that needed some work. Got new flywheel, starter, and carbs rebuilt to get it running again. Been out twice with same results of running great at first until i kill it out in open water then hard to start up again. Can finally get it started when full throttle applied for about 10 seconds and blue/wht smoke prevails with engine running rough. I can nurse it back to running smooth until i kill it again. Basically runs fine until I stop it! Still have gray fuel lines....need to replace but could there be another problem????
Thanks!

 

[dewmeister]

Had pretty much the same problem.... 97 XP. I changed the gray fuel lines out with hose from Advance Auto and cleaned the filter bowl out. The bowl had some type of residue in the bottom of the bowl that more than likely came from the lines breaking down internally. pull your carb filters they'll probably be black in color and are supposed to be white or natural color. I took mine out to Perdido Bay a few days ago and that seemed to fix the restarting problem. The XP was even nice enough to start when I got it back home so I could flush it out. Anyway start with the fuel lines and carb filters.

 

[Banana Yellow]

Thanks! will replace the lines and clean the carb filters this wkend. Hopefully this will be the fix. Appreciate the info.....

 

[custompartsguy]

two things catch my attention here, you say blue/white smoke and have to hold the throttle wide open, sounds like it may be flooding out and that might be why it also dies on you, next time it will not start pull the plug and see if it is soak and wet with fuel.

 

[Banana Yellow]

Thanks custompartsguy i will look at that next time. I did forget to mention that if i run WOT after about 3 seconds it will start to bog and i can back off to 3/4 and its runs fine then. I also notice another symptom is it will not stay at idle after coming down from a 30-40mph run. Any other ideas?
thanks!

 

[SheaMolt]

That's basically what just happened to my 97 xp, except i was going about 10-20 mph and i heard engine missing so i replaced sparkplugs and it works great now.

 

[Banana Yellow]

Yea replaced the plugs a couple weeks ago....I only notice it running rough after it starts to bog down at WOT. After I back it off it will work itself out to running smooth again almost seeming like its flooding out at top end but that doesn't explain the motor dying after letting go of throttle completely...

 

[spikedbat]

Typically when you can start the engine easily when cold, and then struggle to get it running again once hot, the first thought that comes to mind is low compression, due to worn piston rings. Had the same problem many times on my ski doo's. DOO a compression test and post the results. If your below 115psi I can guarantee thats what is going on. You need new rings.

When the engine is cold, the compression is higher as it has not expanded yet, as it heats up everything expands and you lose compression.