1997 GTX wont go past 6000 rpm

[hard2hitch]

my current problem is a seadoo GTX with a 787 motor from you guys....it was originally installed by a dealer in south Florida (if you wish to see the invoice...i can do that) total time on this motor is 6 hours
in any case, the cooling lines were reversed, oil tank lines left loose, rave valves mis adjusted, gobba goo on the exhaust gaskets, carbs out of sync and misadjusted chokes and oil pump etc. i guess you get the point.......
anyway we rebuilt the carbs...pilot needles 1 turn out
pop off 41psi on mag and 42psi on PTO (close as i could get it)
high speed needles closed.....159 degree valve set at 142
SBT gaskets all around without the gooooo
stock exhaust and stock the whole way around
pump and shaft IS aligned (wonder if the "dealer" even owned an alignment tool ???
engines fires off properly and idles at 1450 fine.....
When accelerating it comes up to 6000 rpm but slowly........ my SBT powered 2000 700 single carb Virage smokes it !!!!
i tried to pinch off the water line from the water regulator to the pipe at the pipe and it bogs down to 4000-4500 rpm
the top line goes to the pipe, the bottom line Ts to the inlet line from the left most port at the back of the boat the feeds the intake side of the motor and the return line from the head exits out the right side port on the left side of the hull....the little squirter is working when engine is on......pipe does not seem to get very warm nor is the head getting very warm......any ideas???????
note there is some water in the hull when riding but i cannot isolate the source.....the gasket surfaces of the motor are not leaking yet ????? what???
its coming from somewhere...i am extremely frustrated and willing to pay have someone look at it and fix it......but i seem to know more about it than any dealer i have been to....(thats so sad)....maybe that's why i work on these things.....!
any assistance or suggestions would be greatly appreciated this ski has 6 hours on this motor and if i have to bring it to SBT or to ????? to pay someone to fix it i will (if you have anyone that does that) even on the side???? the installing dealer really did a number on it and we have not been able to use it because of how it runs (wife is stressed which means my life is hell as you can probably relate)

[Technical Support]

Re: 1997 GTX wont go past 6000 rpm

Did you already try the things I suggested in my email?

[Bill O'Neal2]

Re: 1997 GTX wont go past 6000 rpm

FYI,
When the water regulator is doing it's job correctly, there is still some amount of water that goes to the pipe. When you pinch off the line, no water goes to the pipe.

A better water regulator test is to put the boat in the lake and remove the small waterline from the regulator at the pipe, hold it overboard, rev the motor and see if the water stream diminishes. It should not completely shut off, but only be a trickle of what it is at low rpm. You can also visually see if water is leaking from the water regulator onto the muffler, another sign that the regulator needs replacing.

Next test to try: Place a multimeter set at 20Vdc on the positive terminal of the battery. Start the motor and rev it to 3000 + rpm. It should read over 13 Vdc. If not, replace the rectifier in the grey box.

[hard2hitch]

Re: 1997 GTX wont go past 6000 rpm

Thank you once again for the information, i will check the water flow and i am also in the process of getting a new water regulator. Funny that you mention the voltage regulator since we use a float charger after every use to keep the battery at 100% but the low 12 v indicator on the intrument cluster always flashes low 12v.
so i will check that also.....
john

[hard2hitch]

Re: 1997 GTX wont go past 6000 rpm

OK, i did the voltage test at the battery with the boat in the water.....voltage at 3500 rpm was 13.9 vdc..... replaced the water regulator still sluggish to 6100 rpm but i did find a water leak between the large pipe and the second smaller pipe at the squeeze clamp...re did the exhaust install and will try to get the boat in the water for another lake test....any other suggestions on getting this thing to spin up to 6800 rpm?????
the low 12 v light flashes until the boat is started...yet the batter tests out to 12.25 volts.....we also checked the battery connections
thanks
john

[Bill O'Neal2]

Re: 1997 GTX wont go past 6000 rpm

Well, an exhaust leak will certainly cause a motor to not perform properly. Let us know what it does now, but make sure it is sealed up good when you test it. Those pipe joints can be hard to seal properly.

Did you know a battery with 12.25 volts is about 30% below what it should be to be fully charged? Doesn't mean it is shot, but it does mean it only has about a 70% charge.........

[hard2hitch]

Re: 1997 GTX wont go past 6000 rpm

ok bill..... now we are getting somewhere...the exhaust leak is solved as is the water coming out of the pipe into the boat, that change along with the water regulator change allows the boat to spin up much quicker and all the way to 6700 rpm however the water line test over the boat does not do what you said.....pull it off the pipe from the regulator and overboard.... at idle the water flow is constant and steady...but accelerate the motor and the water flow INCREASES....N O T deacreases, WHY????
thanks
john

[Bill O'Neal2]

Re: 1997 GTX wont go past 6000 rpm

How high did you rev the motor when testing the water flow ?

At high rpm, the water should decrease in volume. If it did not, you would not be seeing 6700 rpm across the water when riding it.

[hard2hitch]

Re: 1997 GTX wont go past 6000 rpm

bill... I bow down, you are the man!!!!! i only ran it 4000rpm and you must be right i will try to run it today again at WOT to see
thanks
john

[Bill O'Neal2]

Re: 1997 GTX wont go past 6000 rpm

If you are seeing 6700 rpm, the water regulator works fine. You had an exhaust leak.

[RICHRICH36]

Re: 1997 GTX wont go past 6000 rpm

Bill I had a similiar experience with my 98 GTXL today. It ran fine for about 3 hours around 6700 and after that I could not get it past 6000. When I got it home I noticed the rubber coupling after the exhaust pipe ruptured and it looks like it shot water and exhaust against the side. I did a compression check and it was 140-140. Would this cause the low rpm and if so could you explain the theory behind it. I will be calling you on Mon to get the replacement part.


Thanks

[cerv96xp]

Re: 1997 GTX wont go past 6000 rpm

if you have an exhast leak your loseing back pressuer causing low r.p.m,s

[Bill O'Neal2]

Re: 1997 GTX wont go past 6000 rpm

When an exhaust hose leaks, it fills the engine compartment with carbon monoxide fumes. When the carbs are opened using the throttle, it sucks carbon monoxide into the motor instead of clean air, that is why the motor goes dead rich and loses rpm. The worse the leak, the worse it runs.