problem with 97 spx wont rev above 1500??? rpms

[markkellyjr]

ill start with the history of the jet ski.... got it on trade, newly rebuilt bored 400 cc over stock. I donno if thats true or not but thats what he told me. Got it home dropped in water, idles fine, but as soon as you go to give it gas.. it starts to come out of the hole, then dies. Before the motor stops spinning you can hit the start button and it will start back up no problem. it wont rev over 1500-2000 rpms in or out of water. i know it will tear it up,but if u tap the start button when it starts to die, it will stay running but the rpms get higher and higher the more you do it. So i know its not a fuel problem.... if it helps it smokes like hell. Feels super strong for the time it stays running. i was told it could be the rev limiter.. if so where is it located and how do you adjust? Any ideas?Thanks in advance for the advice. o and its a 717

 

[kustomkarl]

Welcome to the seadoo forum markkelljr. It sounds like you need to remove the carburetors and clean them. If you're careful and don't tear or damage the diaphragms you won't need to buy a rebuild kit. Pay attention to the internal filters too. If you have gray fuel lines you need to replace them with black fuel lines available from auto parts stores like Auto Zone. Measure the length you need and bring a sample with you so you get the correct size. Replace one at a time so you don’t get them mixed up. If you need clamps replace them too. Use small stainless steel clamps also from the auto parts store.
I hope this helps.

Karl

 

[markkellyjr]

if its the carbs then why would it continue reving up if you tap the start button everytime it goes to die. it acts if you were to hit the kill switch.but it starts right back up??? i have no clue with jet skis, im a motorcycle guy. i thought i could fix it with my knowledge of bikes but they are nothing alike.

 

[kustomkarl]

What is happening is that the engine is off. The starter is firing it up again and the unburned gas in that small instant is still being pumped by the engine pulse line to the diaphragm of the carb, which in turn is still pumping it into the engine. The fuel is being fired and is allowing the engine to rev up freely with the extra fuel. I would start by doing a compression test and check the carb adjustments. The Low speed should be 1 1/2 and the High speed should be "0". The high speed screw has a cap on it the low speed screw has a pin through it. The carbs still might have a problem if it has the gray fuel lines on it. They deteriorate from the inside out, and clog the internal filters.
Let me know how you make out.
Do you have a seadoo shop manual? If not here’s an idea for you. You could join as a "premium member". As a premium member you can down load a authentic seadoo manual from the seadoo manual library. In the library is a variety of manuals for almost all years and models. You can view as many as you like on line as a PDF file, or download it and print it for your personal and private use. There are operator manuals and repair manuals for you to do your own repairs on your seadoo. The repair manuals have everything from troubleshooting, repair procedures to winterizing. It contains wire diagrams torque specs and pictures for disassemble and assemble instructions. In the spec sheets it tells everything needed to maintain oil changes, spark plug gaps, carburetor rebuilds and impeller wear ring tolerances. Click on the "Seadoo Manuals" link at the top of the page for more details. If you need any help or get in a jam, we are always here to answer your questions too. Premium members get priority when it comes to getting quick detailed answers.


Karl

 

[JPX]

The fuel system is creating flow with the pulse tube. But if there is any restriction the system will starve itself out. But when you turn it off and restart, you get a surge of fuel that lets you start, maybe even rev high briefly, but then it sputters itself out.

Not getting enough fuel makes it run bad. Keep doing it and the fuel mixture leans out to the point you start inviting engine damage. Mid 90s Seadoos are quite prone to carb clogging because of those cursed grey fuel hoses - we hear about it all the time on here, and I have personally experienced it on my own Seadoo.

 

[derek]

400 cc's over stock? nope. you hafta buy aftermarket jugs to get it to 750 cc's. 1100 cc's is beyond possible.

 

[markkellyjr]

that makes alot more since to me now,thanks a bunch!!!!!! as far as the 400cc over i kinda figured he was pullin my leg.i was born at night but not last night. but i really wasnt for sure about it considering jet skis and bikes are alot different. i kinda figured if it was 400cc over it would be pushin a big block piston. it looks completly stock from the outside.it does have the grey fuel line, and i do have a shop manual.but i was really considering joining as a prem. member. thanks guys for all your help and i will let you know the outcome. thanks again.

 

[kustomkarl]

Keep us posted and if you need any more help, give us a shout.

Karl