60 m.p.h. max on my 2005 RXT? What the heck!?

[KefirSeaDoo]

So check it out.....I just dropped $1400 to rebuild my supercharger on my 2005 RXT, plus I changed all the damaged parts in the Oil Separator and PTO Assembly.

I took the PWC out yesterday to the ocean....it was really choppy, tho and I had a full tank of fuel, but I could not get my Max. speed to register past 60m.p.h. The ski was very responsive and you could hear the SC working beautifully.

Aren't I supposed to be able to hit 70mph with this thing?

 

[kustomkarl]

If it was really choppy then the pump isn't hooking up like it should. What has the been the record of the past use in the same conditions? Did you also hit max rpm's? It might also be the wear ring is in need of replacment if it maxes out rpm's and not the top speed.

Karl

 

[KefirSeaDoo]

Karl,

Thanks for taking a moment to reply. The record of the past use in the same conditions was 50m.p.h., but was only b/c I was running the PWC with a blown supercharger. Since the repair, I took it out to the same location with even choppier conditions and was hitting 60m.p.h.

What are the max rpm's for my 2005 RXT IC Supercharged that I should be looking for? My mechanic disassembled the entire ski when he pulled out the engine. Wear ring (plastic housing around impeller?) is in tip-top shape together with the condition of the impeller.

By the way, he used Prestone 50/50 coolant for the PWC. Is that ideal?

 

[feld1128]

Max RPM should be 8000 mine sometimes hit 8150-8200

 

[KefirSeaDoo]

What speed are you reaching at 8k rpm? Do you notice any slow down in speed with the extra weight of a full tank of fuel?

 

[Dr Honda]

I think officially, that ski only does 64 mph. So, a slightly warn, wear ring, or a little extra weight on it... then yes... 60 MPH would be about right.

The RXP was the 70 mph ski.

 

[feld1128]

Both of mine hit 68 to 69 mph full of fuel and before and after supercharger rebuild.

 

[rford09]

My 05 RXT with the rebuit charger will do 70 on the speedometer( i know there inaccurate)with a full tank of gas and my big 350 pound butt on it.

 

[TyGuy]

There are a numerous things that could be causing you to lose power. A few things you might want to check are
- Weak spark
- Too much engine oil
- Clogged fuel injectors
- Throttle does not open fully
- Low fuel pressure

Those are only a few of the things that might be wrong. Or your engine could be running too fast and that would also prevent you from being able to reach your top speed. Start at one spot and begin checking things off the list that are not wrong and that should help you narrow down your issue.

 

[Michael211_2000]

So check it out.....I just dropped $1400 to rebuild my supercharger on my 2005 RXT, plus I changed all the damaged parts in the Oil Separator and PTO Assembly.

I took the PWC out yesterday to the ocean....it was really choppy, tho and I had a full tank of fuel, but I could not get my Max. speed to register past 60m.p.h. The ski was very responsive and you could hear the SC working beautifully.

Aren't I supposed to be able to hit 70mph with this thing?

Near 70 mph in good water conditions, in choppy conditions with full tank of fuel I'd expect a few mph less. You might want to check your oil level though, it's possible your mechanic has overfilled the engine crankcase with oil. The oil level with the engine warm should be right in the middle of the bend on the dip stick, not at the top of the bend that would be overfilled!

- Michael

 

[KefirSeaDoo]

I'm frustrated with this whole RPM and MPH on my 2005 RXT

1st off, thank you everyone for the input on my issue.......So I took my RXT out again this weekend with 1/2 a tank of fuel and my 210lbs self on it and once again, can't get it to sustain anywhere between 65-70mph. Water conditions were relatively calm and the ski was hookin' with the ocean water.

One thing I noticed is that my RPM's are not exceeding on ANY of my runs, past 7500-7600 RPMs.....GPS speed logged in at 58.8 mph.....Speedo skips around, but shows no speed greater than 62mph....I want to see this freakin' thing do 65-70mph.

I am after a supercharger rebuild, after the ceramic washers got pulverized into the Oil Separator and PTO Assembly.....I hope no damage was sustained to the internal parts of the engine...What's up with the PWC not being able to achieve the 8K RPM?

I'm takin' this bitch back to the mechanic and running through the list of probables that were provided via this thread (thank you for that). I will keep you posted and please share any additional ideas anyone may have.

 

[Michael211_2000]

Hmmmm.... how many hours are on your engine? Are you the original owner? Did it ever turn 8K rpm's?

New plugs right? You are apparently missing some rpms, those last few hundred that would put you up over 65 mph in good conditions. Have your mechanic check the compression on each of the cylinders too, just in case 1 has low compression! Also wouldn't hurt to check the throttle cable and be certain it's opening the carb to full throttle... you never know, but it really could be just that simple.

Let us know what your mechanic finds out! It helps everybody out.

- Michael

 

[KefirSeaDoo]

Partial results!

Okay,

So I took the PWC to my independent mechanic today who hooked up the 2005 Seadoo RXT S/C to his B.U.D.S. unit and did a thorough check. I found it rather interesting that the B.U.D.S. diagnostic shows you a complete graph for an RPM profile and allows you to disengage any one of the three cylinders of the engine as a means of checking adequate performance.

So I printed-out this thread and took it with me, with all of the wonderful and logical suggestions that you guys pitched (thank you again for that).

The short of the long is that there was too much oil in the engine. He had to have pumped-out at least 3/4 to 1 quart of motor oil.

Not only did I have a recent service performed on the watercraft, I also had the supercharger rebuilt together with the replacement of the oil separator and the PTO assembly.... all of this required a significant amount of engine oil in comparison to your typical service.

I ran through the entire list of troubleshooting that was provided via this thread.... we used the B.U.D.S. diagnostic to make sure that the throttle body was fully opening ( Degree reading for the sensors of the throttle body were at the desired 0.00)

We quickly revved the engine dry, to see how high the RPMs were registering and were able to achieve 8200 RPMs.

Oil level on the dipstick reaches the upper portion of the bend on the stick. The oil used for the service was a semi synthetic SeaDoo XPS oil recommended for the 4- TEC supercharged engines.

All that is left now is to get this bad boy in the water (hopefully tomorrow morning) and see if I can squeeze-out close to 8200 RPMs@65-70 m.p.h.

By the way, the LCD was displaying a "Maint" message that we were able to clear out. This message appears after a certain amount of hours on the watercraft.... in my case it was 66.8 hours.

Thanks all!

Kefir

 

[Michael211_2000]

Interesting.... thanks for sharing your results. Hope you have a great ride with it in the morning!

- Michael

 

[Coastiejoe]

It will be interesting to see if you gain both RPM's and speed...
Let us know....

 

[xdaily]

Good info on this thread as Im only able to hit 60mph myself (non gps reading) and I noticed my oil level at the top of the bend.

 

[Coastiejoe]

I got mine out for the first time about a week ago. I noticed my RXP was a bit slower than I had expected. I will be hitting the lake again today and will look at my oil once it is warmed up...