02 GTX DI Top speed suddenly only 47mph?

[Dizzyduzit]

Hoping i can get some feedback from the forum here...when i bought my (not the one pictured on my profile) 2002 GTX DI 2 years ago top speed was around 55-58mph which appears to be about right, it also had good torque in turns...my son even said he could easily toss a passenger by just taking a quick turn and goosing it out of the hole! This summer when i took it out it seems to max out at 47-48mph, and has almost no torque into the turns and takes forever to get back to speed .... put new plugs in but didn't seem to make much difference?? checked the underside grates for sticks, sea weed etc, nothing there. Any suggestions on what could be sapping the power on this thing? Would a new impeller make a difference? plug wires? any additives to clean fuel injectors etc? HELP! No one wants to drive it now as its just so sluggish. Don't think fuel delivery is the issue as we also put a new fuel pump in (was stalling and showed clear signs of bad fuel pump and it was sluggish bf we did that anyway). I didn't swap the exterior fuel filter but did put a new internal fuel filter in when we did the fuel pump. Anyway, any suggestions are appreciated!!

 

[mikidymac]

You need to see if the engine isn’t reaching full rpm or is the engine at full rpm and the ski just doesn’t go like a clutch slipping. Depending on which one will go down a different diagnostic path.

 

[Dizzyduzit]

ok, that makes sense.. before i take her out and check... can u advise what full RPMs should look like on this 02' gtxDI?

 

[mikidymac]

6,900 rpm

 

[Dizzyduzit]

Hey - so I checked the Rpms and they seem to be about 7500 when going max speed. But again, still really sluggish when coming out of a turn. It used to take right off - now it takes a bit to get back up to speed. Def not like it was. Any info on how exactly to check the fuel Presure now that I have a new fuel pump? So I need to have it in the water to check w gauge? And where do I even hook the gauge to?? Sorry- I really am pretty handy just new to jetskis

 

[Ckrawiec]

Sounds like this is going down the "physical/mechanical path"...if the engine is running like hell but the ski a'-int keeping up....I'm thinking you need to start thinking wear ring (i.e excessive gappage between the impellor blades and the ring itself - 18 years old...has the ring ever been replaced before???)...clearances are supposed to be miniscule so as the ring wears, so does the performance.....might be as "simple" as pulling the pump and replacing the ring to get you back to where you were speed wise.

 

[jhjesse]

It’s probably not your fuel pump. They usually either work or they don’t. Certainly won’t get 47mph if it were the fuel pump.
I guessing:
Wear ring/prop
Rave valves
Compression
Water control valve leaking

 

[Dizzyduzit]

OK. thanks guys. Ive got a guy thats gonna look at it. I'll advise these items as a good starting point. Ill circle back with an update!

 

[etemplet]

Check the wear ring first. That's very typical. Loss in speed, torque, and high RPM on the tach. Mechanical slippage. Good Luck !! From what I see in my area the shops charge around $300 for a wear ring job. 2hours X $110, cost of wear ring ($50), neoprene gasket ($12) supplies and tax.

 

[XPLORx4]

It’s pretty easy to change the wear ring. You’ll need 10mm wrenches to take off the steering, reverse bucket, etc. 13mm socket and extension for the Venturi assembly, and 17mm to pull the pump. Once the pump is out, you can inspect the wear ring and impeller. Replace parts as needed.

When reinstalling the pump, apply new grease in the impeller splines. .Apply a light coating of grease around the pump seal to help it seat easier. You may need to reach over the top of the pump to get the driveshaft into the impeller as you reseat the pump, and sometimes a slight rotation of the impeller is needed to line up the splines.

While the pump is out, it’s also a good idea to change the anti rattle/tail cone oil.