96 XP Hesitating at Full Throttle

[eatpez]

First off let me think everybody who contributes to this forum because I picked up a pair of 96 XPs last year. Since that time I've been working on them, devouring all the content on this forum, and completed rebuilding the rave valves, the water pressure regulator, the carburetors, replacing the fuel lines, and running all the factory shop manual tests on both.

I'm on vacation this week out at Silver Lake Sand dunes and finally splash them. One of the them isn't running so well I'm going to check on that one in the next day or two but the other fire's right up and it's running beautifully with the exception of one issue that I'd like to discuss with you guys.

When I run it at wide open throttle, it alternates between pulling my arms off and then hesitating for a second as if it's fuel starved then it picks up again, pulls hard and the process repeats itself. So she pulls hard for two or three seconds then it'll hesitate for two or three seconds then it'll pull hard. At first I thought it was just cavitation but my nephew confirmed my assessment.

I'm suspecting that it's fuel starved and that the high speed carbs screws need to be adjusted but before I get into doing that's kind of stuff on the water I wanted to check with you guys for your thoughts opinions and wisdom.

Thanks in advance,
Jerry

 

[eatpez]

I wanted to add after reading some other threads hit the car rebuild kits were factory kits, the fuel and oil filters were both changed, the bilge is good and dry, and the fuel system passes the pressure test.

When I picked up the skis they had been sitting outside for 7 years so I did siphons out both of the tanks until they were completely empty although I did not remove the tanks and flush them out completely.

 

[eatpez]

I also replaced the ful check valve and rebuilt the fuel selector switch. But that reminds me that I didn't try switching from on to reserve and seeing if the issue persists when it's pulling fuel from the reserve feed.

I'll do that this morning.

 

[eatpez]

Tried turning high speed screws out 1/4 and running from reserve instead of on. No difference in either case. Definitely getting fuel starved at WOT.

 

[Saludadoo]

check your voltage
My 96 voltage is climbing to 17 volts and it wont rev past 4k

 

[tpiner]

First off let me think everybody who contributes to this forum because I picked up a pair of 96 XPs last year. Since that time I've been working on them, devouring all the content on this forum, and completed rebuilding the rave valves, the water pressure regulator, the carburetors, replacing the fuel lines, and running all the factory shop manual tests on both.

I'm on vacation this week out at Silver Lake Sand dunes and finally splash them. One of the them isn't running so well I'm going to check on that one in the next day or two but the other fire's right up and it's running beautifully with the exception of one issue that I'd like to discuss with you guys.

When I run it at wide open throttle, it alternates between pulling my arms off and then hesitating for a second as if it's fuel starved then it picks up again, pulls hard and the process repeats itself. So she pulls hard for two or three seconds then it'll hesitate for two or three seconds then it'll pull hard. At first I thought it was just cavitation but my nephew confirmed my assessment.

I'm suspecting that it's fuel starved and that the high speed carbs screws need to be adjusted but before I get into doing that's kind of stuff on the water I wanted to check with you guys for your thoughts opinions and wisdom.

Thanks in advance,
Jerry

Jerry, I had the same issue. Went through everything I could think with no luck. Did the carbs, fuel filter, gas lines, changed corroded fuel selector switch....still ran like crap....then I saw a YouTube video on Rave valve cleaning. Took mine apart and there was 1/4" of black sludge everywhere. Cleaned everything and reinstalled. Runs absolutely perfectly now. It's an easy fix. 1 hour max.

 

[eatpez]

Jerry, I had the same issue. Went through everything I could think with no luck. Did the carbs, fuel filter, gas lines, changed corroded fuel selector switch....still ran like crap....then I saw a YouTube video on Rave valve cleaning. Took mine apart and there was 1/4" of black sludge everywhere. Cleaned everything and reinstalled. Runs absolutely perfectly now. It's an easy fix. 1 hour max.

I rebuilt the RAVE valves with kits and cleaned the blades in my ultrasonic cleaner. I'll double check them tomorrow.

My current thought is that the pop off pressure is too high and the carbs are starved for gas, then recoup, then starve, etc. Because it only happens at WOT.

 

[Grnbeano]

Jerry, I had the same issue. Went through everything I could think with no luck. Did the carbs, fuel filter, gas lines, changed corroded fuel selector switch....still ran like crap....then I saw a YouTube video on Rave valve cleaning. Took mine apart and there was 1/4" of black sludge everywhere. Cleaned everything and reinstalled. Runs absolutely perfectly now. It's an easy fix. 1 hour max.

I clean RAVE valves about every 5 outings.

 

[POPPS]

I had a 720 once,,,at full throttle,,,it would cut out and hesitate,,,seemed like the key being removed,,,I went thru every electrical system on the boat,,,so finally,,,For the hell of it,,,I pulled the carbs off,,,cleaned all the orifices,,,including the jets,,,visually found nothing,,,put them back on...and voila,,,problem solved,,,

 

[etemplet]

I have the same problem with my 96' XP. Just at the very top it pulls and lets up about 1 second intervals but it is not a significant drop or acceleration. Feels like I could get another MPH or 2 out of it if it would stay hooked up. I'm not sure what it is but it runs about 56mph. LOL I think about pulling, cleaning, and giving the carbs a good once over but there is only about 5 hours run time on the skis since I did all the work. Never know though... like Popp's said, "pull and clean and the problem goes away." It happens.

I think I opened the high speeds as you did and with no change as you had. Good idea on checking the raves.

Good Luck. I'll be following

 

[POPPS]

The pilot jet orifice is very small, and can become partially blocked with a small fragment,,,as can the main jet,,,pull out the pilot screws and high speed screws,,,make sure they are clear...seems like a fuel interruption issue.

 

[eatpez]

Raves fine. Going to check voltage at battery at idle and at speed next. Another thread mentioned if you have a bad voltage regulator it'll overworld the battery and trigger the rev limiter.

I can run it steady just past 2/3 throttle around 45, but any faster than that it alternates between pulling my arms off like it should and hesitating just like the ignition is dead.

I'll keep you posted. Three days left to mess with it out here on the water.

Starting another thread about the other ski in the pair.

 

[mikidymac]

I would bypass the selector and strainer to be sure. run a line directly from the RES fitting on the fuel baffle to the carb.
You can't "clean" the fuel selectors, they need to be replaced.

 

[eatpez]

That's a great suggestion. I'll give it a shot and report back.