97 GTX surging and wont accelerate

[Trooper182]

Ok so yesterday I took the ski out and ran for a few hrs. While riding I noticed if I let the ski idle for a while and try to get on it it would act as if it was starving for fuel. After a min it would slowly build up to speed. All day couldn't get it to go above 6k rpms. Also noticed that occasionally it had a hard time accelerating but if I hit a wake and the impeller revved it would clear up. Got home and was doing a flush and found a hole about dime size in the rubber exhaust coupler. Replaced it and took it out today. Made it a few hundred feet from the dock and lost power. Wouldn't go above 3.5k rpms at full throttle and occasionally would surge to 6k and fall back down. Got it back home and hooked up to the hose to flush and it would rev all the way to 7k with no issue. Things I have already done since purchasing the ski.
1. Replaced all fuel lines and filter, cleaned fuel tank.
2. Replaced oil lines and filter, purged air.
3. Cleaned RAVE valves.
4. Cleaned carbs and filters but didn't rebuild.
5. Cleaned fuel selector valve.
6. Bought brand new battery.

Checked the rectifier and above 5k rpms was getting about 13.5v. The water valve looks like it was recently replaced and is set flush with the black ring. Wear ring has been replaced. Before I drop 100 on a carb rebuild kit is there anything else I should check? Also if I buy the kit are there any additional things I need to get?

 

[JJinSC]

You cannot clean the fuel selector. Trying to only makes their issues worse. Temporarily bypass the fuel selector by connecting the reserve line to the separator/filter inlet and try it.

The fuel selector sucks Air and can cause those symptoms.

 

[Trooper182]

You cannot clean the fuel selector. Trying to only makes their issues worse. Temporarily bypass the fuel selector by connecting the reserve line to the separator/filter inlet and try it.

The fuel selector sucks Air and can cause those symptoms.

Thanks, im going to go ahead and order a new selector valve. But why would it run crappy on the lake but rev fine on the trailer? And should I consider rebuilding the carbs or wait?

 

[JJinSC]

There is no load on the engine when it’s on the trailer. It takes very little throttle and fuel to get high RPMs

 

[GGuillot]

What's the compression on the engine? When you do the carb rebuild be very detailed, use everything that comes in the OEM kit, including the HS and LS needle orings. Set the carbs at 1 turn out on the LS needles. You can tweak the HS needles later, but I never run them shut at zero, I crack them to about 1/8 out on my 787 skis.

Pick up new OEM needles/seats and check the pop off psi after you get them together. Sync carbs dead on, and recheck all the cables, throttle, choke, and oil pump.

 

[etemplet]

I had carb trouble like that with my wife's ski. I pulled the carbs 4 more times finding the sweet spot and I have two GTXs 1996 mine 1997 wifes. I adjusted both carbs the same and both performed the same except hers had an issue and wouldn't get over 37mph. Then she'd hit a wave and the ski would accelerate great. I believe it was the transition provided by the 3 holes in the carb barrel. Those have to be clear. There are actually 4 holes. I found that for us in our area 36psi pop off worked best. As I post many times, her ski is still faster than mine.

On a side note, I just replaced the engine in my ski and I found an issue with the exhaust hose and a couple other small items. After I break it in I'm gonna give her a run for the money. LOL good luck with your ski.

 

[Trooper182]

Ok so went ahead and ordered rebuild kits for the carbs, expensive stuff. While I'm waiting for parts I tested the pop off on both carbs. Both popped off at 35psi over multiple tests. Looked at the springs but cant tell if they were black and one point or are silver. Noticed PTO carb is leaking air around the seat. Thinking the oring is not sealing properly. Also pulled the fuel filter and found lots of gunk in the bottom of the bowl and on the filter, inside and out of it. Also the filter looked like it was being squeezed. This was a new filter I installed 2 weeks ago. Installed before I replaced the fuel lines. So while I'm at it I am going to flush all the fuel lines and clean the filter up then pressure check everything. I do have another new filter but will wait to use that if needed.

 

[GGuillot]

Both popped off at 35psi over multiple tests.

On both of my 787 skis, that's what I was getting on each carb, 34-35 psi. Sounds like you have the correct 80 gram springs, I had ordered new springs, along with new seats/needles with the kits.