'98 Seadoo SPX can't go past 1/2 throttle

[claydwg]

My '98 SeaDoo SPX revs fully doing a water test on the trailer. When riding it on the water it will not rev past 1/2 throttle. It seems like there is a restrictor plate on it.

I have replaced all fuel lines, rebuilt the carbs, new spark plugs, new gas filter, new battery, fresh gas and oil.

If anyone has any suggestions I would appreciate it.

Thanks

 

[hwoolfolk]

I had that problem this year. First time out and it would stall just after getting up on plane. I replaced my fuel lines (had the old grey lines) and siphoned all the old fuel... fresh fuel. Ran fine after that.

 

[claydwg]

Yup, did all that before I took it out this year. I took the rave valves out and cleaned them. They were pretty gunked up. Also I have one compression spring missing on the front rave valve. Where it went, I don't know. I'll put one on and try it out tomorrow.

 

[seadooya]

the missing spring, wont constitute a 1/2 throttle rev. Whats your rpms at, at 1/2 throttle?

 

[claydwg]

I don't have a tachometer to measure rpms. I'll pick one up this week.

 

[rgiana25]

You did not mention the fuel selector valve.... Did you check for flow? Clean it? You should remove it and inspect the 3 ports. If there is any blue residual junk from the fuel lines on it, you can assume that the selector is not flowing very well. You should replace this part.... for $20 or so, it is a nice insurance item in assuring your fuel system is operating properly.

 

[claydwg]

I forgot to mention that. I did not replace the valve but inspected it and it's clean as a whistle. I also cleaned the filter at the bottom of the baffle. That was fine as well.

Would the water regulator valve have anything to do with this problem?

 

[seadooya]

I forgot to mention that. I did not replace the valve but inspected it and it's clean as a whistle. I also cleaned the filter at the bottom of the baffle. That was fine as well.

Would the water regulator valve have anything to do with this problem?

determines where your rpms are at. If stuck at 5k, then the W.R., could be play'n a role. got one, if need be.

 

[claydwg]

Put a new spring on and took it out, still have the same problem.

I took the water regulator out and it looks fine.

I know I'm not getting up to 5k rpm. It probably only goes 15mph. Starts accelerating fine then once I'm at half throttle it stays there and stops accelerating. My throttle cables and carbs are opening where they should be.

Again, this only happens in the water, in the trailer on the ramp it goes full bore.

 

[claydwg]

Update - I got it on the water after a little more tweaking. It responded right away to WOT and was fine for about 15 min. Then I let off the gas and it died. I couldn't restart it and had to paddle back to the ramp. When I got home I notice that the MAG spark plug was fouled and a small amount of gas in the bilge. The PTO side was clean.

After searching the forum some more I saw that DRHONDA has been telling people that third party carb rebuild kits can cause a lean/rich fuel mixture condition which is what I used. I know my mixture is rich. Can I adjust my low speed screws to compensate or do I have to rebuild the carbs with Mikuni kits?

If I can make adjustments can someone give me a tutorial on how to adjust the fuel mixture.

Thanks

 

[seadooya]

clay, if yuo got your original parts, from the carbs, re-install them, as lonag asthe diaphram looks good, no holes in the black part of it, then you can re-use them. Did you install the kits' n/s springs, when doing rebuild? If so, find the oem ones, and re-install. With mag carb wet, and in bilge, then i'd suspect the "hole" thats on the diapgram plate, is bleeding, so your needles are being stuck open, from the POS aftermarket kit you used.

Tear carbs back down, set lsa/hsa to fact. settings, then we'll go from there.

 

[claydwg]

The original diaphragms are damaged. They hadn't been replaced in 12 years. I did replace the springs and think I still have them so I'll put those back in and try to find some better diaphragms this week.

 

[claydwg]

Problem Fixed. I put the Mikuni diaphragms in and it runs great! Thanks for the help!