1996 seadoo sdeedster with twin 717 engines

[gravia]

Any pros out there might know some possibilites that would make our speedster lose power in an engine left or right side only in the water after a few minutes? Carbs are clean, filters clean, plugs a little fouled. But one engine seemed to go to the rev limit in park while cruisin, then one day the other did the same thing...Engine revs only to 3-4k rpm full throttle, the other fine!
I havnt taken it back into the water since replacing one cylinder head because someone put a heli coil in crooked and it was leaking around gasket. Maybe that was an issue? I also had frozen fuel shut off valves that I bi-passed and ran hoses directly to carbs from baffle. Maybe they were not open fully..?
I pulled out the neutral switch and checked it, looks fine. The fuel may be a little old, and it has about 1/4-1/8 of a tank.
Any suggestions appreciated, thanks!

 

[timmyboy76]

after doing the carbs, you make sure the "lines" were installed on the right fittings?

Next time out, when its act'n up, pull the choke, see if the motors "spool" up. If so, then you have a fuel delivery issue.

 

[gravia]

Well, the lines were already cut and tailored so its hard not to of put them back in place. And its funny, well not really funny, but when it first went into the water it seemed fine the first time we took it out. Then after a few minutes we noticed the tach on the l/s engine wouldnt go over 3k or so, then we kinda limped back to shore on the r/s engine. Then on the trailer when I went to check it out they both ran strong as hell in gear while flushing. I made some checks and took it out the next day and the right side engine wouldnt tach over 3k now!! Thats when I bi-passed the frozen fuel shut off valves, found the leak around the pto spark plug on the r/s where the helicoil was done, replaced the head with a good used head and new gaskets. I aslo synched the carbs as per the manual. Im now keeping my fingers crossed that when its in the water it will be fine. If its not, and only acts up in the water, what could that be?
Thanks for your response!!

PS
What would you recommend as the best spark plug for this engine for a fair price?

 

[custompartsguy]

restriction somewhere? No matter what it is always doing it now but only one engine at a time either or, or only a problem with one engine?

while in the water you are creating a load, out of the water the impeller is high and dry no load on the motor!

Also when you hit the max rpm's at that time lets say 3-4000 rpm does it just sit there or rev up and down, if it does rev slightly or major how slow/fast...or like I said does it just peg at say 4000 rpm and just sit there without loosing or gaining rpms?

 

[gravia]

Hi, When the engine is at full throttle it will just sit there at aprox 3k-3.5k rpm. Just like the shifter is in park, and the rev limiter is in effect.
I jst put 4 new ngk plugs, and am going to fill it with fresh fuel, then tomorrow will try it out.
I understand that just like a car, under load will cause different systems. But why wont it clear out?? When it did that, it just stayed there!
I think both engines are running a little rich, but I made the factory 1 1/4 air/fuel adjustments when I set the carbs up so maybe thats normal.
Thanks for your fb!