Greetings and sorry for the TL;DR but I wanted to try and avoid the Q&A wasting of anyone's time,
I am new to the forum and joined, as I would like to start working on two "unique fixer upper opportunity" Seadoos that I bought over the summer for my daughters. I am mechanically inclined but new to 2 stroke Seadoos, and PWC ownership in general. I have all the manuals, and a basic understanding, but this problem would best be addressed with the depth of experience here. If I fail to fix it, I will take it to a shop, but considering the age of the machines you have to find the "right" shop and that is another entire line of research in the Dallas area. I have two Seadoos, a 2001 GTS and a 2003 GTI LE. I am working on restoration of the cosmetics, fixing gel coat chips, seats, plastics, gauges, hoses etc. now. They both run and importantly don't fill with water, and other than the 03 GTI LE running a little richer than necessary, the GTI is mostly useable and fun.
Now to the problem with the 01 GTS, I am stumped. Keep in mind there is a lot going on here, I admit that. This was the first time to take them to the lake and run them and they had been winterized/de-winterized only this year by the previous owner. As far as I know the GTS had not been run this season maybe in over a year, so yep, old gas etc. I know there is a laundry list of possible causes but again, wait for the punch line.
1. GTS was hard to start, just never seamed to pull enough fuel with the choke. Ended up using starter fluid which it started up immediately and after a few seconds would idle fine, no serious concerns. Restarts and idle after it was warmed up were not an issue.
2. Once in the water the throttle response was ever so slightly slow (you had to ease the throttle while still relatively cold), I would have suspected it of running lean but if so just barely (have not done a plug analysis yet).
3. Here is the problem, the GTS will only accelerate to about 15-20 mph (I don't have a speedometer/tach, only a fuel/oil light gauge on this very basic model), this is at full throttle. It runs smooth, no bogging, no coughing, and importantly NO INDICATION of cavitation or jet pump issues. The speed/thrust follow the throttle, just no full (high speed) throttle. The throttle throw feels linear until the last 1/3 of the available actuation then that last 1/3 results in no additional engine RPMs (sound) or thrust/speed.
4. My daughter was a little bummed at this point since between these two very cheap PWCs, this was the one "she picked" so... now Dad has to fix her "slow boat" (calling all dads!) Got on it with her to confirm throttle response, cavitation, etc. Yep, full throttle was not there. Here is the kicker, we decided to ride it around full throttle (guessing about 20 mph, barely on plane) and see if the carb would clean out (treated fuel) or whatm either way needed to see if anything else was wrong to build my repair list. Nothing changed, until we hit a good size wave from a wake boat... we had the throttle fully open when this happened, and as soon as the Seadoo hit the water it revved and we were off to the races. Instant performance, leap forward, almost knocked me off! Importantly though it didn't "sound" like an over rev, but I don't have a tach.
5. This dragster power boost startled my daughter who released the throttle quickly. When we applied full throttle again the GTS would only accelerate to the previously mentioned 20 or so mph. The throttle behaved EXACTLY the same as before hitting the wave. Ok, so now I know the PWC can run, just have no idea as to what the wave had to do with it.
6. Same day, same run, time to repeat the experiment... we drove around until we found another decent size wave (keep in mind that at our slow speed it takes a pretty big boat wake to get it to catch a tiny bit of air and even then really just the nose comes out of the water). Finally found one and as directed she was prepared and held the throttle full open. As soon as the PWC hit the wave we launched, I don't know the speed or the RPMs but it sounded like a good running PWC, we were flying and actually a bit faster (this GTS has a new wear ring installed) than the GTI LE, I'm guessing around 45-50 mph. We ran it like this for maybe 5-10 minutes until we finally needed to slow for some tighter turns that my daughter was uncomfortable with at full tilt. All the while the engine sounded smooth, the jet pump had no feeling or sound of cavitation, everything was good with the world... until we let off the throttle about half way and we again returned to 1/3rd speed.
Notes about the above, no combination of movements of the throttle or choke would result in the above behavior. I tried reseating the spark plug ignition cable boots just in case one plug was intermittent, no difference) The choke engaged while running would kill it as it should, aggressive and rapid throttle agitation would cause the motor to sputter a bit as expected with a carburetor (acceleration pump/pop off valve rapid actuation). And this "hit a wave/bump" behavior was able to be replicated two more times before the wake boat left the area, and I could not longer find a large enough wake to "jump." Basically as long as we held the throttle open while "fixed" it would speed along smoothly and happily.
One thing I could not determine from the above tests was whether the acceleration of the engine was happening while the boat was slightly in the air (unloaded JP) or only when it "hit" the water after (the physical jarring of the water impact). As we were not traveling very fast going into the wake crest I really didn't feel or hear the jet-pump suck in air (fully out of the water) and the engine accelerate rapidly "before" coming back down into the water and just "keeping" it's new RPMs. It "seemed" to be the slight "impact" of hitting the water that caused the burst of speed. But on this point I am unsure, it was happening rapidly and we only got to do it three times before the wave source left the lake.
So, could it be a carburetor issue? Of course, in fact if the acceleration was occurring while the jetpump was unloaded airborne but continued with power once back in the water, I would suspect vacuum issues and general rebuild calibration may solve it as the carb may just not opening enough until the engine sucks in a lot more air at full RPM. However, if the above boost is not happening while the jet pump is unloaded, but when the boat returns to gravity so to speak, then I am stumped... A loose electrical connection would be the more likely explanation but with such a very specific behavior where to start? Could the motor be running on one cylinder until the jolt and then off we go? No idea. Again, looking for guidance from the best source - other people's experience on the forum or maybe a benevolent mechanic/technician.
As far as I can figure, there is no way to test any repairs in "dry dock" so, I have to have a plan before trips to the lake to test and this could get really time consuming since I have no idea where to start. I would obviously like to avoid unnecessary repairs and rebuilds in a shotgun approach to the problem solving... but wish in one hand and .... in the other. Please also know that I am not intending to fully restore these PWCs to new condition, trick out the engines, performance mods etc. These are just for my kids to have fun in the summer on occasional trips to the lake.
Thank you very much for your time and help!
Cheers,
Cash
PS, yes my daughters have both completed the Coast Guard Safety Course and TPWC Licensing requirements and we have insurance, just in case someone had an eyebrow up! ;-)
I am new to the forum and joined, as I would like to start working on two "unique fixer upper opportunity" Seadoos that I bought over the summer for my daughters. I am mechanically inclined but new to 2 stroke Seadoos, and PWC ownership in general. I have all the manuals, and a basic understanding, but this problem would best be addressed with the depth of experience here. If I fail to fix it, I will take it to a shop, but considering the age of the machines you have to find the "right" shop and that is another entire line of research in the Dallas area. I have two Seadoos, a 2001 GTS and a 2003 GTI LE. I am working on restoration of the cosmetics, fixing gel coat chips, seats, plastics, gauges, hoses etc. now. They both run and importantly don't fill with water, and other than the 03 GTI LE running a little richer than necessary, the GTI is mostly useable and fun.
Now to the problem with the 01 GTS, I am stumped. Keep in mind there is a lot going on here, I admit that. This was the first time to take them to the lake and run them and they had been winterized/de-winterized only this year by the previous owner. As far as I know the GTS had not been run this season maybe in over a year, so yep, old gas etc. I know there is a laundry list of possible causes but again, wait for the punch line.
1. GTS was hard to start, just never seamed to pull enough fuel with the choke. Ended up using starter fluid which it started up immediately and after a few seconds would idle fine, no serious concerns. Restarts and idle after it was warmed up were not an issue.
2. Once in the water the throttle response was ever so slightly slow (you had to ease the throttle while still relatively cold), I would have suspected it of running lean but if so just barely (have not done a plug analysis yet).
3. Here is the problem, the GTS will only accelerate to about 15-20 mph (I don't have a speedometer/tach, only a fuel/oil light gauge on this very basic model), this is at full throttle. It runs smooth, no bogging, no coughing, and importantly NO INDICATION of cavitation or jet pump issues. The speed/thrust follow the throttle, just no full (high speed) throttle. The throttle throw feels linear until the last 1/3 of the available actuation then that last 1/3 results in no additional engine RPMs (sound) or thrust/speed.
4. My daughter was a little bummed at this point since between these two very cheap PWCs, this was the one "she picked" so... now Dad has to fix her "slow boat" (calling all dads!) Got on it with her to confirm throttle response, cavitation, etc. Yep, full throttle was not there. Here is the kicker, we decided to ride it around full throttle (guessing about 20 mph, barely on plane) and see if the carb would clean out (treated fuel) or whatm either way needed to see if anything else was wrong to build my repair list. Nothing changed, until we hit a good size wave from a wake boat... we had the throttle fully open when this happened, and as soon as the Seadoo hit the water it revved and we were off to the races. Instant performance, leap forward, almost knocked me off! Importantly though it didn't "sound" like an over rev, but I don't have a tach.
5. This dragster power boost startled my daughter who released the throttle quickly. When we applied full throttle again the GTS would only accelerate to the previously mentioned 20 or so mph. The throttle behaved EXACTLY the same as before hitting the wave. Ok, so now I know the PWC can run, just have no idea as to what the wave had to do with it.
6. Same day, same run, time to repeat the experiment... we drove around until we found another decent size wave (keep in mind that at our slow speed it takes a pretty big boat wake to get it to catch a tiny bit of air and even then really just the nose comes out of the water). Finally found one and as directed she was prepared and held the throttle full open. As soon as the PWC hit the wave we launched, I don't know the speed or the RPMs but it sounded like a good running PWC, we were flying and actually a bit faster (this GTS has a new wear ring installed) than the GTI LE, I'm guessing around 45-50 mph. We ran it like this for maybe 5-10 minutes until we finally needed to slow for some tighter turns that my daughter was uncomfortable with at full tilt. All the while the engine sounded smooth, the jet pump had no feeling or sound of cavitation, everything was good with the world... until we let off the throttle about half way and we again returned to 1/3rd speed.
Notes about the above, no combination of movements of the throttle or choke would result in the above behavior. I tried reseating the spark plug ignition cable boots just in case one plug was intermittent, no difference) The choke engaged while running would kill it as it should, aggressive and rapid throttle agitation would cause the motor to sputter a bit as expected with a carburetor (acceleration pump/pop off valve rapid actuation). And this "hit a wave/bump" behavior was able to be replicated two more times before the wake boat left the area, and I could not longer find a large enough wake to "jump." Basically as long as we held the throttle open while "fixed" it would speed along smoothly and happily.
One thing I could not determine from the above tests was whether the acceleration of the engine was happening while the boat was slightly in the air (unloaded JP) or only when it "hit" the water after (the physical jarring of the water impact). As we were not traveling very fast going into the wake crest I really didn't feel or hear the jet-pump suck in air (fully out of the water) and the engine accelerate rapidly "before" coming back down into the water and just "keeping" it's new RPMs. It "seemed" to be the slight "impact" of hitting the water that caused the burst of speed. But on this point I am unsure, it was happening rapidly and we only got to do it three times before the wave source left the lake.
So, could it be a carburetor issue? Of course, in fact if the acceleration was occurring while the jetpump was unloaded airborne but continued with power once back in the water, I would suspect vacuum issues and general rebuild calibration may solve it as the carb may just not opening enough until the engine sucks in a lot more air at full RPM. However, if the above boost is not happening while the jet pump is unloaded, but when the boat returns to gravity so to speak, then I am stumped... A loose electrical connection would be the more likely explanation but with such a very specific behavior where to start? Could the motor be running on one cylinder until the jolt and then off we go? No idea. Again, looking for guidance from the best source - other people's experience on the forum or maybe a benevolent mechanic/technician.
As far as I can figure, there is no way to test any repairs in "dry dock" so, I have to have a plan before trips to the lake to test and this could get really time consuming since I have no idea where to start. I would obviously like to avoid unnecessary repairs and rebuilds in a shotgun approach to the problem solving... but wish in one hand and .... in the other. Please also know that I am not intending to fully restore these PWCs to new condition, trick out the engines, performance mods etc. These are just for my kids to have fun in the summer on occasional trips to the lake.
Thank you very much for your time and help!
Cheers,
Cash
PS, yes my daughters have both completed the Coast Guard Safety Course and TPWC Licensing requirements and we have insurance, just in case someone had an eyebrow up! ;-)
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