Leak testing your exhaust pipes
When rebuilding your Pro 785 or trying to diagnose an issue of low or lost RPM's, it is very important to leak test your stock exhaust system. Although the pipes are strong and reliable, there are times where they will crack causing a small leak that can rob you of power. Using the test procedure below you can find any leaks in your pipes and if need be, send them out to be repaired.
Equipment needed:
- Air pump with pressure gauge and 3/8 ID hose (click here for picture)
- Rubber hose caps (click here for picture)
Procedure
Depending on the pipe setup you have there are a few different ways to leak test your pipes. If you have pipes from a 1997 ski, you should already have 1/8 NPT brass plugs installed in the pipes. If you are running a newer setup, you should go buy some 1/8 NPT plugs from the hardware store and insert them into the threaded hole closest to the stinger with teflon tape.
Once your plug is installed, you will need to connect your air pump to the nozzle closest to the engine side end of the pipe, as shown in the picture below. Next you will want to block off the remaining nozzle with a rubber cap. You can purchase these at an auto parts store. The tube coming out of the stinger end of the pipe is not part of the test and can be left alone.
Next you will want to pressurize the pipe to about ten psi. It should be able to hold this pressure for three to six minutes. Watch the pressure gauge carefully to see if it decreases at all. If it does you have a leak and you need to find it!
The best way to find a leak is by preparing a soapy solution. Get a spray bottle and simply fill it with water and dish soap, then you spray it on areas of the pipes where you think might be a leak. Always check the threads where your plugs and hose fittings screw into the pipes. If they are not tight, or aren't sealed properly, they will leak. These are easy fixes and can be cured by simply tightening the fitting or re-sealing them with new teflon tape or a good marine sealant.
