Ultra 250x cuts out

[Mems]

Hi
at idle the ski hunts between 600-1200rpm for about 5 seconds and returns to normal....
Ski hits 7650 rpm and was 96kmh (not on gps)
the battery light comes on when immobiliser key is installed, had battery checked and all good...
mainly happens after itÔÇÖs warmed up and do a wot run and let off throttle and it will cut off, ski starts instantly again when hitting start button...
any more I can think of I will add
thanks

[Region8Ultra250X]

the intake horn could be sucking itself to the hull and choking the motor

[Chris288]

idle air control valve ( IAC )

[Mems]

Thanks for the replies...

update on what ive done since and I will add that the ski is fine until about half an hour of riding and when mostly running wot and letting off throttle and quickly getting back on it will stall, not very fun when your mid turn.

1. battery has been replaced...
2. IAC valve has been replaced and this fixed the hunting idle and is night and day better but stalling problem still persists when letting off throttle at WOT
3. Intercooler has been flushed and cleaned with fuel...
4. Compression was 100psi +/- 2-3psi in each cylinder, this was done cold and with a repco comp tester, throttle body was uninstalled at the time (unsure if that matters) and also unsure of comp tester reliability. Will try with a different brand tester when available....
5. Spark plugs look good but will probably be my next small step

i haven’t tried the air box horn and it may be coincidence or not but every time it has stalled the ski has 4 or less bars on the fuel gage, roughly a third of a tank....

ski has been out recently with rxpx 260 2015 model and the ultra is neck and neck in speed, rxp has a slight mid range advantage

[Mems]

Bump

[Chris288]

The plugs on 250's only last 20-30 hrs before fouling out guaranteed... replace with cheaper cr9eix iridium

[Offshore Aussie]

The plugs on 250's only last 20-30 hrs before fouling out guaranteed... replace with cheaper cr9eix iridium

+1

[Shaun_dodds]

Hi
at idle the ski hunts between 600-1200rpm for about 5 seconds and returns to normal....
Ski hits 7650 rpm and was 96kmh (not on gps)
the battery light comes on when immobiliser key is installed, had battery checked and all good...
mainly happens after it’s warmed up and do a wot run and let off throttle and it will cut off, ski starts instantly again when hitting start button...
any more I can think of I will add
thanks

Did you ever fix the cutting out problem? Mines starting doing the same thing. The revs will drop too low and cut out if you let off throttle to fast.

[Scott]

Did you ever fix the cutting out problem? Mines starting doing the same thing. The revs will drop too low and cut out if you let off throttle to fast.

did you pull the plugs to give them a good look over? I remember 250x's had a problem with exhaust gaskets leaking and allowing water back into the cylinders thus fouling the plug.

[Shaun_dodds]

did you pull the plugs to give them a good look over? I remember 250x's had a problem with exhaust gaskets leaking and allowing water back into the cylinders thus fouling the plug.

I pulled the plugs and they are fine. Is it normal for the throttle cable to be a little slack st the throttle body end when the throttle lever is not pulled?