Rave Valves

[lauren bailey]

i pulled out my rave valves to clean them and found that on each engine one was broken now my seadoo challenger 1800 run fine other than the fact of lately it wont do past 36mph. are my broken rave valves the cause of my sudden lack of power? can someone answer this question PLEASE!!!!!!!!!

 

[kustomkarl]

Yes that is more than likely the culprit. Here is some information on the RAVE valves concerning annual cleaning.


RAVE VALVE annual cleaning

________________________________________The RAVE, (Rotax Adjustable Variable Exhaust) valves are located above the exhaust valve. There are 2 of them per engine. They are round with a red adjustment screw in the middle. It has a clip that holds it together. How they work is that they open the exhaust port larger as the engine rpm's increase. When the rpm's drop down so do the RAVE valves. They work on the principle of the pressure of the exhaust system. Rpm's increase, pressure increases and the valve opens, rpm's drop pressure drops, Valve closes. They should be de-carbonized annual. To disassemble the rave valves, remove the spring clip on top, remove the black cover. There is a spring under the cover. Remove the piston by turning it with a metric socket. On the bottom of the piston is the rubber "Bellows". Be careful with the small retaining spring that holds the bellows on the piston. Remove the 2 allen screws that hold the base on the cylinder. Remove the base and gasket. The long valve won't fall in the cylinder just pull it out. There is an o ring under the base, on the shaft of the guillotine valve. Be careful to see how it came apart as it has to go back together that same way again. On the base, notice the notch that it is facing down. Clean all the carbon off the guillotine valve. I use carb cleaner and 400 grit paper. Check the bellows for any small pin holes. If so, replace it. If not, reassemble it on the clean guillotine valve, and install it back on the engine the same way it came apart. The guillotine valve only fits one way. The one closest to the exhaust pipe will come off differently then the other one. You will have to remove the allen screws and turn the base so it clears the exhaust pipe. I would do one at a time in case you forget how it goes back together again. This way you can look at the other one and copy it. Do both engines 2 per engine, if so equiped. Take your time and if you have questions give us a shout. We'll be here to help you out.
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.

The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.

I hope this helps.

Karl

 

[seadooya]

i pulled out my rave valves to clean them and found that on each engine one was broken now my seadoo challenger 1800 run fine other than the fact of lately it wont do past 36mph. are my broken rave valves the cause of my sudden lack of power? can someone answer this question PLEASE!!!!!!!!!

No...but could have contributed to loss of compression.

Remove the sparkplugs and do compression test. If numbers are within 10% and neither cyl is under/say 110psi, then your good to go.

Install new sparkplugs, remove the boots' ends (sparkplug boots), clip the wires 1/4in and re-install boots. If carbs are good/clean, you'll get back your 48-52 mph, with the 7k rpm.

All raves do, is control the exhaust "release", to keep the motor/pipe in the "sweet" spot, for max rpm delivery. Depending on how bad, they're chipped up, it'll contribute to "slow" wot reaction.

 

[lauren bailey]

ok but im getting 7000 rpm the speed just isnt there!!!!

 

[Rampage]

then I would look elswear then the RAVES..I would more think slight cavitation.

 

[kustomkarl]

If your seadoo is quick to hit top rpm and going nowhere, it is cavitating. Check the clearance of the wear ring to the jet pump for the proper clearance.

Wear Ring clearance for your seadoo 1.0 mm or (.040in) Measure the clearance at the center of the impeller blades, with a 12” long gauge. Measure the clearance from the venturi side of the jet pump.

Karl

 

[lauren bailey]

Thanks guys i will have my husband check on that this weekend!!!!

 

[lauren bailey]

i have one more question will we have to take off that jet pump in order to remove the wear ring?

 

[kustomkarl]

Replacing the wear ring


For starters....

1.) Remove the three hoses on the inside of the boat. (Attached to the pump) if you do not do this first, you will forget and cause all kinds of problems for yourself!!!

2.) Remove the steering rod, 10mm bolt and nut.

3.) Remove 4 13mm bolts holding nozzle on. with this off you will have a much better view of the wear ring.

4.) Remove 4, 17mm bolts from the pump to hull. Make sure you pull off all the lock washers and washers to ease pulling the pump.

5.) This is the tricky part.... Most shops gob all kinds of silicon on when replacing the pump and so it makes it a pain to pull it away from the hull.
You need to pull the pump away from the hull as straight as possible.

They sell a pump removal tool but I just made my own. Cut a length of 2x4 that I set across the rear of the ski and drilled 2 holes in it. I thread long 13 mm bolts with washers through the top two holes of the pump where the nozzle mounts. This pulls it away nicely with a butterfly impact.

6.) Now you have your pump and impeller in your hands, the next step is to remove the 3 8mm bolts on the cone. Make sure you have something to catch the oil and nose plugs.... This stuff reeks to high heaven...

7.) After cleaning out the oil I place the pump impeller side up in a vice. (grabbing the flat end of the pump shaft in a vice)

8.) Place impeller removal tool in the impeller and grab a 1/2" drive 3/4 socket with a huge breaker bar. Twist it counterclockwise till it pops loose. (May take some pressure. I seriously use a 4 foot pipe on the end of my breaker bar and use a popping motion rather than smooth pressure.)

9.) Now that you have the impeller out take your new wear ring and put it in the freezer.

10.) You have to get the old wear ring out of the pump. (I have found the easiest way is to take a saws all and cut a slit in the wear ring the full length of the pump) Be careful only to cut the wear ring and not the pump.

11.) Take a large standard screwdriver and a hammer and tap the screwdriver gently between the wear ring and the pump all the way around to separate them.

12.) Clean all the white corrosion off the pump where you will be putting the new wear ring

13.) After tackling this task go to the freezer and grab that wear ring. (don’t dilly dally with it) get it to the garage and slide it in the pump. you may have to tap lightly with a rubber mallet. If it doesn’t slide in then you didn’t clean the pump good enough. Repeat steps 9 and 12.....

14.) Reinstall the impeller in the reverse order.

Note: it is very important not to pinch the thrust washer when re-installing the impellor shaft. That’s why it’s a good idea to do it in a vice rather than on the ground sideways.

Once the impellor is tight you should have 1/8 - 1/4 inch play in the shaft back and fourth. if you don’t start over and inspect your thrust washer you probably pinched it..

15) Inspect the rubber o ring and if it is good apply silicon and reinstall the cone. Make sure the allen fill plug is on top.

16) Lower the front of the ski and add oil to the cone. When it is full, take a brake and have a drink. There is air in the cone and when you go back you will see that it is low. Top it off and take another brake... do this until the fluid does not lower again. I often start the ski for a few seconds to make sure oil is all the way worked into the bearings and all the air is out.

17) wipe silicon on the set screw and screw it in (be sure not to run it all the way into the cone. just deeper than flush is fine. let it sit 24 hours to cure the silicon and put the nozzle back on.

18) Use Sea Doo 75w90 GL5 Synthetic Polyester Oil or similar.

I hope this helps.

Karl

 

[lauren bailey]

is there some site where i can download pictures of this job?

 

[RFoster130]

Good write up with pics:


http://seadooforum.com/showthread.php?t=30720

 

[lauren bailey]

Thank you very much the pictures were helpful!!!! i have another questio how do we find the right impellers for a 1999 seadoo challenger 1800? we found some solas sd-cd-16/24 are these the right impellers for our boat?

 

[RFoster130]

call impros.com they will hook you up with what you need.

 

[lauren bailey]

does anyone know if sbt rave valves are worth buying?

 

[100guard]

...Wear Ring clearance for your seadoo 1.0 mm or (.040in) ...

wow...that sure is close.