won't run above 3,000 rpm!!

[kustomkarl]

Well 2nd launch of my 97 Challanger 787 and it started right up but as on the first trip if I leave the throttle in the center position it wants to take off. so learned to point it out from the dock, start it up leave throttle on lowest position it purrs like a kitten. run it at fast idle it has a sound like it is starving for gas....kinda like "brom brom brom brom brom" (nice sound effects) with it in gear no difference. Even with it running on dry dock, on hose for only couple minuts it makes the same type of sound in high idle in netural...sounds normal at low idle, it's smooth. I notice if I go from high idle to low idle it takes a couple seconds to smooth out, not real quick respons to throttle down. I think I will start with basics, Compression test, than pull carbs apart and check float levels and main jets for blockage. I already pulled the RAVE valves and clean all the carbon off the slide valves and checked for any cracks or dry rot on the bellows,looked fine.
Replaced the plugs with fresh ones,Br8es. Now about the rotory valve anyone ever had any experience with it causing a starving problem? On the first launch , new plugs ran like 45mph with 2 of us for about 4-5 minuts...than this problem.... the fuel isn't fresh( 2 months old)but it dosent have a foul odor and the oil injector is working, with seadoo oil, as far as I know. well if any one has any other Ideas I am open for a suggestion. It runs like crap but it looks peerty..lol make a great planter for the yard.
Thanks Karl

 

[seadoosnipe]

Runs good!

Karl, you said when you first took it out, that it ran around 45 with two people in the boat. That's about top speed for the Challenger with two. I hit just over 50 with a bit less than half tank, smooth water and a windless day. My question. When you were running at 45, did you notice anything that may have happened? A back fire, any noise, or any clue that can help to lead in the direction of, why it won't get any faster now? The reason is, for it to be the rotary valve, you should have heard something. If the rotary valve cover is off to the high side, it can cause hard starting problems, off to the low side will cause it to backfire. If the rotary has "by itself" lost time, then the backlash to the end gear where it meets the crakshaft can be off. But none of these problems should exist if you were running good on that day you took it out and hit 45mph, unless you heard something happen? My gut feeling is Carbs..........

 

[kustomkarl]

Karl, you said when you first took it out, that it ran around 45 with two people in the boat. That's about top speed for the Challenger with two. I hit just over 50 with a bit less than half tank, smooth water and a windless day. My question. When you were running at 45, did you notice anything that may have happened? A back fire, any noise, or any clue that can help to lead in the direction of, why it won't get any faster now? The reason is, for it to be the rotary valve, you should have heard something. If the rotary valve cover is off to the high side, it can cause hard starting problems, off to the low side will cause it to backfire. If the rotary has "by itself" lost time, then the backlash to the end gear where it meets the crakshaft can be off. But none of these problems should exist if you were running good on that day you took it out and hit 45mph, unless you heard something happen? My gut feeling is Carbs..........

Well today I did compression check 150# each...checked carb linkage, enough spray grease to choke a seamonkey! At further glance with sparkarester off it apears one carb isn't returning closed... all gunked up! Well I removed the carbs, and am going to rebuild them. I hate when someone selling you something lies about how it was just in shop and carbs were re-built and serviced. I called the name of shop she droped in conversation, talked to service dept. They knew her and told me she was told of couple problems but didn't want to spend the money...(only paid for evaluation of $25.00)Rave valves might need bellows, and carbs need rebuild and of course fuel guage need replacement...geez I found that out the hard way. oh well it looks pretty, lol checking on carb kits now ..local stocks them normal but only 1 on shelf till thursday..$50.00 each...I'm gonna look around for better price.!!

 

[seadoosnipe]

Carbs?

Karl, My PTO carb was nearly frozen, would hardly move. I was able to take them off and go through them, loosening up the parts, cleaning them and being very careful with the gasket material so as not to tear them, and put them back together. I didn't put a rebuild kit in and they both run great!...not saying you don't need one, but if the problem is from being gunked up and just tight from lack of maintenance, then you might save a buck and just try to clean them up. I used carb cleaner and cosmoline.
Good luck!........you got my number if you need anything!
Careful when you go to remove them from the motor. Seems that with age, the bolts solidify onto the casing of the carb....like some kinda electrolysis...

 

[kustomkarl]

I got the carbs. off ok. The mag carb has a badly frozen butterfly on the throttle end. I took it apart and the everything inside is ok,diaphragms and needle and seat. This explains slow throttle response from high idle to low idle. The butterflies have lots of corrosion on them and rusty looking. from lack of mantaince. Cost for a rebuild kit is $50.00 ea. ouch! I'm still looking for better price now. I'm also looking for maybe used mag carb instead of fooling around trying to get the shaft from the butterfly replaced or at least unfrozen. I already spent the last 2 hrs cleaning the grease off and removing all the remaining flaked paint, on 1 carb! Rotory valve looks good oil pump and cable looks ok, so not all bad...I think if I get carb unfrozen I will spend money to rebuild and repaint so it won't corrode and cause problems later. I guess it dosen't get any better than this...lol...uh it still looks perrrty..lol

 

[seadoosnipe]

Wow!

That is exactly what was wrong with mine!........it took a little work, but I was able to free and clean it all up with lubricant and cleaner. I didn't have to put a kit in!............good luck with it.
Let me know how it goes!