2001 RX Losing Compression?

[15michael15]

On Memorial day weekend had some guys get on my ski and try to wakeboard from it while I wasn't around to tell them not to. Since then it has been slower out of the hole and the top end has been decreasing, all the way down from ~70 to 35mph.

What's this sound like to everyone? Quick glance at the engine and I noticed one of the large allen bolts holding the exhaust on has sheared off, I'm not sure if this alone would limit back pressure to the engine, I doubt I'm that lucky. The boat will start and run idle fine, no beeps or "MAINT" flashed from the gauges. Any ideas?

Thanks!

-Mike

 

[seadoo GTS 1993]

Whats your compression? Could be possible you runnin' on one cylinder, your plugs good?

 

[15michael15]

Well I haven't measured the compression, really haven't done anything seeing as I just pulled it home from the lake yesterday. It's sitting in my driveway awaiting service. I live in Lexington, KY and travel 2.5 hours to Lake Cumberland to my place. So I'm looking for someone trustworthy to take a look at it in Central KY. Unless someone else has had the problem and thinks I can fix it myself.

I installed new plugs at the beginning of the summer, which doesn't necessarily mean they are good, could be faulty. I was planning on pulling them out and looking them over. I just feel like it's something more serious.

 

[seadoo GTS 1993]

Do the comp. test if you can, if that checks out OK, then we can go from there, keep us posted....

 

[15michael15]

How would I go about doing that? No experience with it.

 

[seadoo GTS 1993]

Remove both plugs, screw in compression guage, crank engine and give FULL throttle.. do it about 3 times for each cylinder and use the average... should be 120 or higher and within 10% of eachother

 

[15michael15]

Oh ok, so that's something I can do myself, i'll need to get a compression gauge...I'll pick one up tonight. Thanks!

 

[seadoo GTS 1993]

yup, compression test is realy pretty simple, and the guage is pretty cheap, Keep us posted on the numbers!

:cheers:

 

[15michael15]

Compression test completed! Each cylinder is dead on 115 PSI. So I'm thinking the pistons and rings are ok. I did notice that the tube coming from the RAVE valves was loose on the solenoid, like barely on at all. Also one of the plug wires felt a little loose when I pulled them off to test compression.

I've read that the RAVE valves need to be cleaned every 30-40 hours, is this true? Anyone have a guide to do this?

Thanks!

 

[seadoo GTS 1993]

115 is fine..... your symptoms sound pretty similar to a RAVE valve issue.. I dont kno how to go about cleaning them tho, b.c I have never owned a ski with RAVE's.... i'll search around on the forum to see if I can figure it out......

 

[seadoo GTS 1993]

Found this from snipe

Here, this should help, found it in Snipes sig. Great info Snipe! :hurray:



Once a year, you should be removing the RAVEs to clean the carbon deposits from the slide valves. This is easily done with brake or carb cleaner. I use a small piece of copper that I've flattened to a "scrapper' type tool. The copper is softer material than that made of the RAVE, so, it shouldn't gouge and is great for scraping of the tough spots.

The most important part of the cleaning is the sides of the slide. And don't forget to clean the grooves of the cylinder head with that copper "scrapper". The carbon that will fall off into the engine while cleaning won't harm the engine. If you use a carb cleaner on those parts of the slide groove on the engine, I recommend that you let that cleaner completely evaporate, then pour about a coke bottle cap full of your two cylce oil into the cylinder (the carb cleaner will remove the cylinders oiling film).

 

[15michael15]

Great info indeed, what would I do to go about removing the RAVE valves? I did run across one post that was very in depth and seemed like it would take some serious time, along with buying new gaskets and whatnot.

 

[seadoo GTS 1993]

new gaskets not needed.. just spray everything down with carb cleaner.... i think theres just a few bolts that u have to remove and then it comes apart.. once u kno how to do it I THINK its a easy/short process..

 

[seadoo GTS 1993]

Now im goin' to steal Karls post :rofl:

see if this helps.....

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 hold 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


BTW.. Thx Karl and Snipe! Ur makin me look good lmao

 

[15michael15]

GREAT! I'll see what I can do with that...I really appreciate everyone that has contributed to GTS' posts, haha! I'll post my status when I get a chance to dive into it.

Oh and I appreciate you, GTS, for compiling the info - new to the forum and not real sure where all to look just yet.

 

[seadoo GTS 1993]

No problem! Glad to help! I hope it is something as simple as just the RAVE's need cleaning... Let us kno how it goes:cheers:

 

[15michael15]

Ok...here's what I did...removed the RAVE valves, cleaned them (with oven cleaner) had them looking good...re-installed them and took the ski out. Seemed to be running somewhat better until about 10 minutes into the ride. The ski became very bogged down and would hardly move at full throttle. After inspection of the engine I found the rubber piece that connects the exhaust together to be busted. A hole blown in the side. I think I might've put the RAVE valves back without adjusting them correctly.

When I put the valves back together, are the valves supposed to be screwed all the way together? Or slightly unscrewed? I can get some pictures of the piece that has the hole if that'll help.

Anyone know what's going on? Any ideas? Pics to come.