Top Speed on a 4tec 2002 GTX

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braindead89

braindead89

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I just picked one of these up and my tops speed is 47 mph. I had another sea doo with me and thats what the speedo said on it too so I don't think it was off. The rpm wide open was in the 7500 range. From dead take off it didn't seem to Have any cavitation , no notable hesitation at all but only 47. Is it possible for the wear ring and impellor be bad but still not have hesitation or is 47 mph normal for this?
 
Yea, it sounds like you have jet pump issues. I would also make sure the reverse gate in the rear is coming all the way up when the shift lever is in forward.
 
I'll definitely check that reverse bucket. Have you ever heard of a jet pump being worn without giving you that "slipping clutch" feeling?
 
You should see about 60 on the speedo and sounds like a pump issue because 7500 rpm is good. Yes, a bent impeller can cause no cavitation at all(slipping clutch feeling) but not reach normal top speed. A worn wear ring will normally cause some cavition. A few things to check: impellor/wear ring, carbon ring seal, OPAS going up all the way, ride plate/shoe seal.
 
You"re describing the effects of moderate jet pump wear. Seems like your RPM"s are a little high also. Not sure but I think 7300-7400 is normal. The rev limiter comes on at 7650. I say this assuming you have a factory impeller in the ski.
 
Ok someone please help me here. I'm totally confused. I was reading a post at another site. Forgive me if I'm not allowed to post it here) http://www.**************/forums/showthread.php?t=63086 The guy starts out with some what the same problem of no top speed. I didn't notice any smoke but the so called dealer that sold it to me said they just changed the oil. I'm not too sure they know what they are doing at all. Do you think this thing could simply be overfilled with oil causing me to have a situation with now power?
 
Heres why I feel the dealer has no clue what they are doing. On craigslist they have 4 machines for sale, 1996 750 Kaw ZXI 1599.00 (Reasonable for the area) 1997 SD GTX, Ready to go, 1699.00 I lift the seat the engine is disassembled, then they had the 02 GTX 4tec for 2900.00 which I bought. THey also had a 2003 Sea Doo XP in perfect shape with 25 hours on it for $1,900.00

I guess I dont know why they had two so cheap and one overpriced then one at a reasonable price unless to say they don't know what they are doing.
 
braindead89 said:
Do you think this thing could simply be overfilled with oil causing me to have a situation with now power?
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Well go pull the dipstick and check the engine oil level. The engine oil level should be right in the middle of the bend in the dip stick. However an over-full engine crankcase will reduce top rpm's and rob engine horsepower, and that doesn't sound like what you're experiencing.

At slower speeds a worn pump will still perform ok, but at high speeds water will get around the impeller blade tips causing loss of top speed. You are almost certainly going to at least need to pull the pump out to take a look at the impeller and wear ring condition, there should NOT be enough space between the impeller blades and the wear ring to slip a piece of notebook paper between them, the tolerances are supposed to be VERY close! Also it could be that the impeller blades are badly dinged up on the leading edges, this would also give good low speed power and accelleration but kill the top end speed.

Until you get it out and take a look at it all anybody can do is speculate though... the concensus seems to be that you have a pump issue going on, not an engine problem. Your RPM's sound about right but your top speed is all wrong which screams PUMP PROBLEM to all of us.

- Michael
 
braindead89 said:
I guess I dont know why they had two so cheap and one overpriced then one at a reasonable price unless to say they don't know what they are doing.
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Always a possibility, the one you bought from them definitely has a problem after all. If they sold it to you as "lake ready" then they were greatly mistaken. If you don't want to figure it out and fix it you might want to take it back and demand your money back because there is DEFINITELY a problem with it!

- Michael
 
Once I find out my work schedule for the day I'll go check the oil level. Its in storage about 20 minutes away. I can put it on the hose to warm it up so that'll eliminate that as a problem. Can I visually see a pump issue with the wear ring still in the machine or do I need to pull the pump to check it?
 
The OPAS paddles are raised by water pressure from the jetpump, as you go faster the pump pressure increases and little water lines running to the OPAS cylinders will raise them. If that hose is leaking water they won't raise and you'll have water inside the hull. If the line is stopped up then they just won't raise up and will cause drag. Other than having somebody else ride alongside you and observe if your OPAS paddles are going up as you accellerate, I don't know how to check for proper operation without taking it to a dealership (they can disconnect the pressure lines and pump them up to the proper pressure to cause the paddles to raise up on the trailer).

To check the imperller/wear ring you really need to pull the pump out. It's not that hard once you get the right end-wrenches/sockets and extension, takes my about 15 minutes to pull mine and same to put it back. The hardest part is the 4 large brass nuts that hold the pump to the hull, you need a REALLY long extension to reach them with a 1/2 drive and deep-well socket, once you have the right tools it's not difficult at all just disconnect everything and remember which bolts/washers went where so you can put them back in the correct locations. Note there is a little waterhose on top of the pump you have to undo the clamp and pry the hose off with a long screwdriver or something so you can pull the pump out, and don't forget to put that little hose back on when you go back together!!!

Consider this good practise, there will be other times you'll need to pull the pump mark my words you might as well figure it all out now, no time like the present! :)

- Michael
 
Thanks Michael211, Been doing some reading on it. I have taken the pump out of my old XP but wasn't sure if there were lots of differences between that and the pump from a 4 stroke.
 
braindead89 said:
I can put it on the hose to warm it up so that'll eliminate that as a problem.
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No, check it cold! If you start the engine oil goes everywhere inside and takes time to drain back into the bottom of the crankcase it can cause you to believe it's low on oil when in fact all the oil hasn't gotten back to the bottom again. If you want to check it warm then you'll need to wait 20 minutes or so after killing it before checking the oil level to get a correct reading, and warm vs. cold oil isn't going to make that much difference oil doesn't expand that much. ps. The hull should be roughly level (ie. eyeball the trailer and adjust the tongue height if necessary to get it about level).

- Michael
 
braindead89 said:
Thanks Michael211, Been doing some reading on it. I have taken the pump out of my old XP but wasn't sure if there were lots of differences between that and the pump from a 4 stroke.
Click to expand...

Ahhh! You should have no problems pulling it then. Let us know what you find! I'm betting the impeller is badly dinged up and the wear ring probably has all sorts of grooves and wear in it (people tend to be rough on these machines and don't realize you shouldn't run them in shallow water they suck up rocks very easily!).

- Michael
 
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