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1997 gtx

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captain scale

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1997 GTX Surging

Hey, haven't been on in a while. No real problems to discuss. Just hadn't used the ski in a few months due to the colder weather. I took it out 2 weeks ago and it seemed to run fine. Took it out again last weekend and it ran for maybe 3 minutes before it acted like it had a fuel clog. I checked the fuel filter, cleaned it an reinstalled along with 2 new plugs. Still ran terrible so I went home. Checked the fuel valve, it's new anyway, so are the fuel lines. Took the carbs off and opened them up and inspected them. No obvious signs of a clog but cleaned the inline filters and scraped out any noticable corrosion, cleaned the jets and put everything back together. Runs fine now! I figured now was a good time to install a primer kit, so I put the plunger under the handlebars where the choke cable was. I also installed an oil block off kit since I was running premix and had the pump disconnected. Now everything is nice and clean looking. I also installed an extra inline fuel filter just before the carbs as a back up! I'm ready to ride!!!
 
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good for you... most people come here to bitch about non-running skis. Nice to hear that you got it running.

Since you went to pre-mix... you did leave the oil hooked to the rotary valve, and gears... right?? (just checking)
 
good for you... most people come here to bitch about non-running skis. Nice to hear that you got it running.

Since you went to pre-mix... you did leave the oil hooked to the rotary valve, and gears... right?? (just checking)

Yes, this is the second seadoo that I have converted to premix. I left the hoses attached to the crankcase on both and left oil in the reservoir. I just grounded out the low oil sensor so I didn't have to keep the bottle full.
 
Uh oh! Seemed to run fine on the trailer after cleaning out the carbs, but still acts like a fuel restriction problem in the water. Gets up on plane quick but surges past 5000-5500 rpms, once on plane I can cruise at around 5000 rpm. If I try to exceed past that the engine surges like it's almost getting enough fuel. If I give it a squirt from the primer plunger it will accellerate and then hesitate again! Everything is clean in the fuel circuit but I should check the screen on the fuel baffle. I may be clogged with bits of varnish that seem to slowly break down from the tank walls! I wonder if I could run it with that sreen off for a little while and let the fuel filter trap what's floating around in my tank. Any ideas? I pulled the caps off the power valves and they are not stuck, no apparent leaks from the bellows. The gaskets in the carbs and fuel pump still look good, the pulse line is clear.
 
could be carb related, water regulator related or rectifier related..if compressions' good.
 
Well after going through the fuel system and not finding any real issues there I moved on to checking the charging voltage. I hooked up my digital voltmeter and ran the ski on the trailer. At idle it's getting over 17 volts steady, so I guess it might be the rectifier, right?
 
Still surging after replacing the rectifier

After hooking up the volt meter to the battery while running the ski on the trailer it started out at about 14 volts but kept climbing to about 17.4V, I reved the throttle and it continued to rise to 18 Volts!!! So I got a rectifier and replaced it and not it charges at about 14 Volts max. I figured my surging problem was solved. I had the airbox off with the flame arrester installed in case I needed to make adjustments. It ran pretty good for a while so I brought it to shore and installed the air box. Then I took it back out and it started to surge again like it wasn't getting a steady supply of fuel. I thought that maybe since I was at half a tank I should switch over to reserve. That only made the surging worse! Then switching back to normal on made no difference! Ahhhh! I checked the charging voltage again on the water and it was 13.5V. So the rectifier is holding up. It's either a leaky fuel valve (which is less than 2 years old) or maybe the power valves need cleaning or I should check the water valve. Hmmm. I may take the fuel valve off and turn it in the off position and see if it holds a vacuum. I should plug the 2 ends also to see if air is coming in through the knob shaft seal!
 
If you get this figured out let me know, I am having the same problem with my 1997 GTX. It just won't take full throttle, it idles like a dream, and run good up through quarter throttle, once I try to go beyond that, it surges between 7000 and 5000 rpm at full throttle, like it quickly consumes fuel, then surges down to rebuild enough fuel, then surges back up then back down real quick. Have a new motor, carb rebuild kits were installed over the winter, and a new o-ring in the filter, and filter is clean and no debris. I don't know what the deal is, but wasn't a real enjoyable first day out on it this past weekend, thank goodness have another ski I could ride.
 
If you get this figured out let me know, I am having the same problem with my 1997 GTX. It just won't take full throttle, it idles like a dream, and run good up through quarter throttle, once I try to go beyond that, it surges between 7000 and 5000 rpm at full throttle, like it quickly consumes fuel, then surges down to rebuild enough fuel, then surges back up then back down real quick. Have a new motor, carb rebuild kits were installed over the winter, and a new o-ring in the filter, and filter is clean and no debris. I don't know what the deal is, but wasn't a real enjoyable first day out on it this past weekend, thank goodness have another ski I could ride.

Did you check your regulator charge output?
 
No I did not because everything seems to be pointing to a fuel issue, or lack of fuel at the top end so was looking into that aspect. Runs perfect idling up through about quarter throttle.
 
when you trailer test the rectifier, do you test at idle or at a certain rpm???...and where exactly is the rectifier located in the 97?
 
Yes, they were set to factory spec for the low speed, which does not seem to have a problem, and all the way in for the high speed, and rechecked by a sea doo mechanic. Actually paid sea doo mechanic to to the carb rebuild, winterize, tune, and everything on my 97 GTX and my 97XP.
 
try this... got the info from a very reliable source... PTO/hsa 1/2 turn out!!! thats how i set mine up after the rebuild this weekend. hooked it up the hose yesterday gripped the trigger straight up to 7000 let off straight back down to 1230 or so and repeated for about 3 minutes... im hoping if it does it on the hose same will be true in the water!!!
 
Is that because on the GTX there is no accelerator pump on the PTO carb like there is on the XP? I noticed that is the only difference between the carbs on the two skis, the 97 XP has an accelerator pump on the PTO carb, and the 97 GTX does not, they both have the 787 engine.
 
dude wish i could tell you... the gtx's are me first rides and i was doin a rebuild this weekend on my fuel system and thats what i was told to do!!!! it seemed to run, idle anr rev great hooked to the hose on the trailer.... hows urs runnin on the trailer?
lemme know when you test it out?
 
hey cap'n, why you put the primer kit on.... what do you gain from that.... not being an ass really, just curious!
 
What are the chances I will have to get an MPEM programmer incase the timing needs to be adjusted? I know the engine is new, and since it is a 787 with a DC-CDI, if I go to check the timing, is it possible it will be off? I know I bolted my mag and everything back on as they were, and they are supposed to be permanent mount. Just thought I would ask since the shop manual does make reference to that.
 
??? hav'nt had to put a new motor in yet homie???? you should make a new thread outta this... you'll get some answers!!! also how are you guy's blowin all these motor's?
 
OK checked electrical out, running it has 13.3 to 13.5 at the battery. That would tell me the electrical should be fine. I don't have the sea doo test plug kit that plugs into the different connections and gives test leads to check, but that reads the same at the battery as my 1997 XP, which is the same motor, and it runs fine so I am assuming electrical is fine. This thing has really got me baffled with the surging at full throttle but runs great at idle up through 1/4 throttle. Also, seems to take the throttle great on the trailer, didn't want to free rev it too long on the trailer though. My RAVE valves are adjusted being level with the top of the caps, and the water valve is also adjusted level with the top. Are these set correctly? I don't know, guess I am reaching at straws here. Also, could the timing be off and require a dealership to use their MPEM programmer to set it correctly? Any help would be appreciated.
 
I was rebuilding a friend's carburetors and noticed that the rivet on one of the regulator diaphragms just about dissintegrated on the outside! What happens if a leak forms at the diapragm? I imagine it could leak air in at low speeds maybe starving the low speed circuit for fuel and possibly leak out fuel after pop off pressure is reached at higher RPMs and could fill the hull with excess fumes and foul out the plugs from running too rich? Wondering if my diaphragms are leaking as well.
 
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