GTI LE RFI idle and low speed issues

[crazytiti]

Hello all, i'm new here with a 2003 seadoo GTI LE RFI i bought 2 month ago and i've ride it 3 times.
I'm facing bad idle and low speed.
Over 4k rpm it's seems fine (my first jet so no real comparison) and it top out at 6800 - 70km/h
I've made a video to help you help me ^^
What i've already done :
- check and clean RAVE valve
- check plug gap -> ok but the plug are BR9ES, i've ordred BR8ES they should come soon
- check and replace air t° intake sensor
- check water t° sensor
- check and clean injectors
- try to adjust idle screw (there's a screw on my 2003 model) it was worse so back to where it ran the better.
- set the oil pump to the mark at idle

You may tell me to reset the TPS sensor, but there's no shop around me to do that (i'm in inner france and jetski are rare)
So i may buy GreenHulk PWC Performance Store - CANDooPro Limited Sea Doo and Can Am ATV Home System (2 stroke 4 stroke) but only in last resort.

About my issues :
- at the start the idle is fine and smooth ~1800rpm then after few seconds it fall to 6-800 rpm very rough with misfires.
I can give a little gaz and it will be back for some seconds then fall again.
I can do WOT then it will be good for few second (up to 10s) and fall...
- the other issue is at low rpm and steady throttle (2 to 3.5k rpm) the motor is not steady sometimes it want to get another 500 rpm and goes back.
Above 4k rpm no problem.
I think top speed is fine because compression is a little low with 120psi on both cylinders.
Motor is said to have been rebuild and got 200hr then on fresh water.
The overall jet is in pretty good shape, nothing has been tampered with, all pieces look like OEM
The plug look like a little too black to my taste, maybe because 9 instead of 8 ?

 

[shamrock246]

I think the RFI’s drop a cylinder at idle not sure what year that started. What oil are you running these take a certain spec. If your planning on keeping the ski the Candoo pro might be a worthwhile investment and the equipment to test the fuel pressure. I think the BR9ES is a colder plug probably not helping things. The 1999 I worked on had voltage regulator issues and they make upgraded units not sure if the 2003 suffered from that issue. I would see if the fresh plugs make it smoother.

Good place for parts
https://osdparts.com/

 

[Seadoo Tuner]

Is that 70kph gps or on the Seadoo's gauge?

These are nice ski's when working well.

 

[crazytiti]

I read about the one cylinder idle, i have the service manual of the 2004 and it said that.
But the 2004 doesn't have the screw to adjust idle and tps is reset at idle position instead of close position.
I think mine should be idling on both ... ?
Yes BR8ES are the one that should be on it (i even have a sticker said that) i hope it will be better with it.
I checked the voltage when running ~3000 rpm and it's good (13.5)
70kph is GPS and the ski, i was surprised at what point it is accurate

Edit : I notice that max power is available at 50-60% throttle, going to 100% doesn't change much if anything.
I checked the throttle linkage and it's good, the throttle open 100% when i have the controller to the handle.
Is it usual ?

Edit : i just download the 2003 service manual and there is a screw to adjust the idle, the reset should be done with the plate totally close.
And the mention about idling on one cylinder is missing thus idle on both cylinder for 2003 rfi

 

[crazytiti]

Last WE i went skiing with my daughter
We spent roughly 1.5h on water

At some point she drives, and since she's ten and it's her first time on a jetski we were going slow (10-20 kmh)
After some times i get back to the handlebars put WOT, the jet was going as usual until soon it loose speed and was going at max 3200-3400rpm whatever how much i push the throttle (like a limp mode)
So we managed to get back to the pontoon at 10kmh and i put the ski on the trailer.

I get the plug out and they were as black as "usual" but one was dry (mag i think) and one was wet.
I think the wet one has fouled and we were going on one cylinder only.
Hopefully i will get the good plugs BR8ES tomorrow.
Waiting this time i have unbolt the head and have seen interesting things.
At first the pistons and cylinders seems very fine to me : small carbon deposit on piston dome, seems ok for 200hours.
The wall of the cylinders still have the honing marks
The mag one have some small vertical trace that you cannot feel with the finger nail.
But when i have cleaned (and a little sanded) the head i found trace of something that broke on MAG cylinder.
So i think the motor was rebuilt with new cylinder and pistons
They's also trace that i don't know what is it. It's like the continents on the earth..

I will put back the motor like this with the new plugs and hope it will be back on 2 cylinders.
What do you think about the head ?