Hi, recently my family bought a nice set of JetSkis and we’re preparing to start breaking in our newest addition, but a problem arose with one of the others. Our RXT 255 iS is quite new to us but already has a lot of time clocked, 220 hours, and upon first putting it in the water I found that it is staying just around 35mph, it will sometimes try to push past it and reach 40mph but then quickly returns to lower speeds. I’ve been doing some research on what could be going on and the only idea that came up was a speed limiter problem, our first thought was that at this many hours the supercharger was in need of a repair. We are currently repairing it but definitely want to know now if it’s something else. If anyone else can give some insight as to what’s going on it would be greatly appreciated. Any more information about the ski is available but as to it’s history we don’t know a whole lot,
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RXT iS 255 topping out at 35mph, NEED HELP
- Thread starter CaseyE
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Update:
Spark plugs are believed to be fine.
The ski is finding a steady speed of 29mph at 5100-5200rpm (5180 to be exact) with peaks of 35 and 45mph. Slow launches peaking at 9000rpm.
The key is read as a regular key
After a few laps on the lake she started to preform better, wasn’t staying at 29 as much but still not doing what it should. Started to peak to high 40s and low 50s.
We tried to load three people on it, well under weight capacity, she idled ok but upon attempting to accelerate she screamed to 8000-9500rpm while maintaining the breakneck speed of 7mph. We did not continue this but she proceeded to run as usual with just me on it.
Spark plugs are believed to be fine.
The ski is finding a steady speed of 29mph at 5100-5200rpm (5180 to be exact) with peaks of 35 and 45mph. Slow launches peaking at 9000rpm.
The key is read as a regular key
After a few laps on the lake she started to preform better, wasn’t staying at 29 as much but still not doing what it should. Started to peak to high 40s and low 50s.
We tried to load three people on it, well under weight capacity, she idled ok but upon attempting to accelerate she screamed to 8000-9500rpm while maintaining the breakneck speed of 7mph. We did not continue this but she proceeded to run as usual with just me on it.
AircraftDoc
Active Member
Spark plugs. Replace them. They fail under load and high pressure rpms.
Digdog
Active Member
There is no way that thing can go over 8500 rpm as the rev limiter stops that, check the impeller to see if something is caught inside it like a stick inside the vanes. Look carefully as it can be hard to see in there, otherwise it's confusing how it can run a high rpm with no thrust and a low steady rpm and steady speed? Just not possible.
I might not have seen the rpms correctly but I’m pretty sure that’s what it was doing with three people on it.
Ok
Ok we’ll get on that soon, our thought is to take it in but we’ll try a good bit first.
Update:
After a second day of testing and riding she’s now capable of doing 50mph with little to no argument. Clocked in about 4 more hours on it and it’s performance has increased greatly but is still not perfect.
Before when I said the rpms reached 9000 I was most likely wrong as I could not replicate it and it always stayed below 8500.
Launches are getting better with one rider, rpms still reach the limit if you just hold it full throttle, I have not been doing that. Two riders strains it more, again reaching rpm limit but this time just quicker and with less throttle, sounds quite displeasing and screams at 6000rpm when trying to ease into accelerating.
Now easily topping out at 50 is way better than 30 or 35, but not the preformance we want, our GXT 265 limited does 70 easily and this one should come somewhat close I assume from all the data I’ve seen.
Plan is to take the ski in on Tuesday and have the spark plugs replaced and probably also have the impeller looked at just incase something is in there, I did hear a weird noise from behind me that sounded like something very quickly banging around loose or something of the sort. This was heard for a very brief time (less than a second) right after I came back to the water after hitting a wave, could have just been the rear side grate that we lost today (purely aesthetic, was half broken already)
After a second day of testing and riding she’s now capable of doing 50mph with little to no argument. Clocked in about 4 more hours on it and it’s performance has increased greatly but is still not perfect.
Before when I said the rpms reached 9000 I was most likely wrong as I could not replicate it and it always stayed below 8500.
Launches are getting better with one rider, rpms still reach the limit if you just hold it full throttle, I have not been doing that. Two riders strains it more, again reaching rpm limit but this time just quicker and with less throttle, sounds quite displeasing and screams at 6000rpm when trying to ease into accelerating.
Now easily topping out at 50 is way better than 30 or 35, but not the preformance we want, our GXT 265 limited does 70 easily and this one should come somewhat close I assume from all the data I’ve seen.
Plan is to take the ski in on Tuesday and have the spark plugs replaced and probably also have the impeller looked at just incase something is in there, I did hear a weird noise from behind me that sounded like something very quickly banging around loose or something of the sort. This was heard for a very brief time (less than a second) right after I came back to the water after hitting a wave, could have just been the rear side grate that we lost today (purely aesthetic, was half broken already)
So ended up not taking it into the shop after all and took our other one in, we are doing on at a time, but we replaced the spark plugs and they looked ok. With the new spark plugs it doesn’t run much better but they’ve been ran just a little bit, we havent checked the impeller yet. Now is topping at 50 but bogs down when doing things such as J-turns, donuts, etc.
Ok now we’ve got a bigger problem, steering is now messed up big time. Randomly it jerked the handles left and locked up, was movable when returning to idle speeds. Limped it home then to the trailer, impeller looks clean but we are gonna look into it more. Red IBR light came on. Rpms shoot up past 7k when going 6mph, also the steering jerks left when reaching a speed over 5ish
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