What would cause this exhaust hose to burst? PICS included.

[97SPX]

The guy who sold me this 97 SPX said his friend ran it through some tall grass and clogged everything up. When they got it running again it burst this hose. He was told it was designed to burst the hose first before building enough pressure to damage anything more expensive. He thought he had cleaned everything out, I'm thinking not. What specifically could cause this to happen now? Clogged RAVE water valve? something in the exhaust. I'm new to all this but not afraid to learn.

Thanks,

 

[97SPX]

Bump. Turns out it's melted. Found a broken spring in the rave water valve and the weep hole was clogged with debris. Cleaned it all up, diaphram seems intact, reassembled with new spring. Hope to test drive it this weekend. This has been addressed to some degree in another thread but feel free to chime in.

Thanks,

 

[kustomkarl]

First off the RAVE,( Rotax Adjustable Variable Exhaust) valves are in the picture on the exhaust side of the engine, with the red caps. I believe you mean the Water Flow Regulator Valve, which is located on the exhaust resonator. Here is some information on the Water Flow Regulator Valve;

The water flow regulator has been calibrated at the factory and should not be tampered with or modified in any way.
CAUTION: Strictly adhere to the calibration procedure or otherwise serious engine damage will occur.
If engine does not maintain RPM or the engine is experiencing poor performance, the water flow regulator valve might be out of adjustment. The normal adjustment as done at the factory is as follows: On the top of the water flow regulator valve locate the red plastic adjustment screw. Mark the location of the screw with a dab of paint for reference. Turn the screw clockwise (tighten) until the top edge of the screw is flush with the top of the black cap. Turn the screw 2 clicks counterclockwise (loosen). This is the factory spring setting. The bottom tapered screw should be screwed in just snug.

This Regulator valve plays an important part in cooling the engine. Each fitting is a special size and controls the flow of water to the different part of the engine depending on the rpm. Never mix up the fittings or you'll have problems with over heating and maybe seizure.

I hope this helps.

Karl

 

[97SPX]

Karl,

Thanks so much for your reply. I mistakenly referred to it as a RAVE water valve because it looks very similar to the two RAVE valves and I saw one on Ebay referred to as a RAVE water valve. Thanks for clearing that up. Your information is a breakthrough though because not only did I find the broken spring and clogged weep hole but the water valve appears to be screwed all the way in which is way out of calibration according to the info above. I have the new spring and will calibrate it per these instructions.

This may be my whole problem with the performance as I checked my fuel strainer and fuel selector switch last night and both appeared very clean. Also the grey fuel lines have been replaced with actual marine grade fuel line at some point before I got it so someone has obviously put some effort and money into the fuel system.

I did clean the rave valves last night, they were fairly oily and had some carbon build up on the guillotines but the diaphrams were intact. (Would not have been brave enough to attempt that without the help of this forum!!)

Thanks very much for the info and I'll report back after the weeekend.