Looking for some insight. I have a 1997 GTX with a freshly rebuilt 787 from SBT installed last summer with new rubber fuel lines (bye bye gray tempo lines). The original engine had a bent connecting rod that seemed to have occurred during winter storage (got 296 hours out of it). This has been a great machine since I bought it in 2018 but has been a headache since last summer and now this summer as well. It has been a freshwater ski its entire life.
Took it out on the water for the first time this year yesterday. Starts up well, idles nicely, but was having trouble getting up on plane (cavitation). I did have a passenger riding with me. I was surprised so I went back to the launch and checked for weeds/debris inside the jet pump housing and intake grate. No debris, so I checked the spark plugs. They were a little dark/wet but not bad — new last year. This same scenario had happened 3 years previously. New plugs solved it no problem then. I replaced the plugs and tried to take off again. Still hesitated up to 6000 RPM, but I pushed it a bit more and it eventually planed out like normal. I thought “great, new plugs fixed it again.” Or so I thought…
Went to the beach for 2 hours and started the ski back up again. Ran good, planed out fine for about 10 mins but then bogged down and began cavitating again? The wind had picked up and we were in some wake (mild whitecap waves) but not sure if that would make a difference? Never had this problem before? Got to the shallows, anchored off, and let the machine sit for another hour. No debris anywhere again.
Went to start it up again and it was really having a hard time starting. Took about 10 tries until it finally wanted to stay running. Anytime I touched the throttle to nurse it to idle, it would stall out and I’d have to retry starting again. Finally worked. Left my passenger on the sandbar so I could see if it would plane out and it was running and driving normally again. Had my passenger jump back on and after 10 mins, started bogging out and cavitating AGAIN in mild wake. I then basically idled to the launch and took it out of the water.
This new SBT engine only has about 3.5 hours on it since it’s installation last summer. Is the machine going into limp mode or something like that? I’m running 50% Stabil-treated rec fuel from last summer and 50% fresh rec fuel pumped from several hours prior. I’ve never had the carbs cleaned/rebuilt during my 5 years of ownership. Is it time? It seems to be running rich. Never had this repeated cavitation problem with the original engine. My wear ring was inspected last summer during the engine install and it wasn’t too bad. Maybe it’s time for a new one regardless?
In summary: machine is running normally, then doesn’t want to maintain throttle response. Acting like it gets “stuck” then revs high with reduced power.
Any advice/help is greatly appreciated!
Took it out on the water for the first time this year yesterday. Starts up well, idles nicely, but was having trouble getting up on plane (cavitation). I did have a passenger riding with me. I was surprised so I went back to the launch and checked for weeds/debris inside the jet pump housing and intake grate. No debris, so I checked the spark plugs. They were a little dark/wet but not bad — new last year. This same scenario had happened 3 years previously. New plugs solved it no problem then. I replaced the plugs and tried to take off again. Still hesitated up to 6000 RPM, but I pushed it a bit more and it eventually planed out like normal. I thought “great, new plugs fixed it again.” Or so I thought…
Went to the beach for 2 hours and started the ski back up again. Ran good, planed out fine for about 10 mins but then bogged down and began cavitating again? The wind had picked up and we were in some wake (mild whitecap waves) but not sure if that would make a difference? Never had this problem before? Got to the shallows, anchored off, and let the machine sit for another hour. No debris anywhere again.
Went to start it up again and it was really having a hard time starting. Took about 10 tries until it finally wanted to stay running. Anytime I touched the throttle to nurse it to idle, it would stall out and I’d have to retry starting again. Finally worked. Left my passenger on the sandbar so I could see if it would plane out and it was running and driving normally again. Had my passenger jump back on and after 10 mins, started bogging out and cavitating AGAIN in mild wake. I then basically idled to the launch and took it out of the water.
This new SBT engine only has about 3.5 hours on it since it’s installation last summer. Is the machine going into limp mode or something like that? I’m running 50% Stabil-treated rec fuel from last summer and 50% fresh rec fuel pumped from several hours prior. I’ve never had the carbs cleaned/rebuilt during my 5 years of ownership. Is it time? It seems to be running rich. Never had this repeated cavitation problem with the original engine. My wear ring was inspected last summer during the engine install and it wasn’t too bad. Maybe it’s time for a new one regardless?
In summary: machine is running normally, then doesn’t want to maintain throttle response. Acting like it gets “stuck” then revs high with reduced power.
Any advice/help is greatly appreciated!
