Hi to all, I have joined the forum in search of knowledge about PWCs. I am a competent handyman & electronics tech with long experience with motorized equipment (starting with minibike/motorbikes in teens - and now retired). Always loved boats, water sports (water skiing, etc.) but avoided PWCs up to now.
I bought a friend's fried '02 GTX 947DI which had no compression on PTO-side cylinder. The piston was not holed, and I found after removing the head that the piston has >1/4" play vertically on the conn. rod, and minor scoring of the cylinder. I expect the wristpin bearing is literally gone (not likely to be larger, cooler running crank bearing). Also evidence of shrapnel in the combustion chamber and obviously there will have been little metal missiles of bearing destruction flying everywhere in the bottom end. I am expecting to swap out the engine for a BRP factory rebuilt unit for long term reliability.
I am wondering what caused this in the first place (engine has 470+ hours on it), and I am thinking it is caused by the engine cooling water inlet screen fitting inside the jet pump venturi being plugged by debris or buildup (looks similar to mineral buildup on a boiler heat exchanger) over the 9-year history of the machine. Found this screen plugged when changing jet pump synthetic oil. I was able to clear the screen using a brass brush, and took pictures before-and-after, could post them if of interest to anyone.
The wristpin is in the hottest part of the engine not directly cooled by water contact, and depends on fuel/oil spray from underside to cool and lubricate it. If cooling water supply was restricted on a continual basis (not enough to trigger overheat alarm condition) the engine could run continually too hot and eventually break down the bearing (not to mention the leaves and acorn pieces I found in the intake air box - left by wintering rodents- could be sucked into the engine and cause havoc).
I did see other posts related to engine failures, always there is the question of why? I am wondering if this issue of the cooling water inlet blocked has been raised before in a post (couldn't find one).
I'm looking forward to good times on the water season, and taking advantage of easy trailering, launching, etc. to explore some new waterways.
I bought a friend's fried '02 GTX 947DI which had no compression on PTO-side cylinder. The piston was not holed, and I found after removing the head that the piston has >1/4" play vertically on the conn. rod, and minor scoring of the cylinder. I expect the wristpin bearing is literally gone (not likely to be larger, cooler running crank bearing). Also evidence of shrapnel in the combustion chamber and obviously there will have been little metal missiles of bearing destruction flying everywhere in the bottom end. I am expecting to swap out the engine for a BRP factory rebuilt unit for long term reliability.
I am wondering what caused this in the first place (engine has 470+ hours on it), and I am thinking it is caused by the engine cooling water inlet screen fitting inside the jet pump venturi being plugged by debris or buildup (looks similar to mineral buildup on a boiler heat exchanger) over the 9-year history of the machine. Found this screen plugged when changing jet pump synthetic oil. I was able to clear the screen using a brass brush, and took pictures before-and-after, could post them if of interest to anyone.
The wristpin is in the hottest part of the engine not directly cooled by water contact, and depends on fuel/oil spray from underside to cool and lubricate it. If cooling water supply was restricted on a continual basis (not enough to trigger overheat alarm condition) the engine could run continually too hot and eventually break down the bearing (not to mention the leaves and acorn pieces I found in the intake air box - left by wintering rodents- could be sucked into the engine and cause havoc).
I did see other posts related to engine failures, always there is the question of why? I am wondering if this issue of the cooling water inlet blocked has been raised before in a post (couldn't find one).
I'm looking forward to good times on the water season, and taking advantage of easy trailering, launching, etc. to explore some new waterways.
