So I have been working on rebuilding my 1998 GTX RFI ski and I would like to share the story of the rebuild process as well as explain the issues I am now facing with this ski. When I first bought the ski, I was told that it was having electrical issues. After a test ride I found that it wasn't charging so I ended up replacing the stator and the rectifier both just to be sure everything was new. This seemed to have fixed the issues with the charging system (more on this later). A few months later, July of last year, is when I began seeing major problems with the ski. The motor was constantly hydro-locked full of oil on the MAG side cylinder after only sitting for a few minutes and 12 volt low errors were occurring. I decided to perform a compression test and discovered that there was not enough compression on that cylinder (duh). After calling a few places and hearing that everyone who rebuilds these motors was pretty backed up with the upcoming summer season, I decided to do a full rebuild on the motor as it had over 250 hours on it and had been sitting for quite awhile before I picked it up. Once I got the motor out, I decided to start tearing it down to see what all I was going to need to replace. After removing the cylinder jugs, I found that the cylinder wall on the MAG side were scored pretty badly and the rings were almost destroyed.
I took the cylinder jugs to a local machine shop who has worked on these motors before and he was able to bore them out .5mm oversize. I decided to go with a complete engine kit to replace the seals on the crank and bearings since I was already knee deep in this project. I then ordered a complete engine rebuild kit from WSM and began tearing the bottom crankcase down. Once open I made note of a few other components and ordered them all so that they would all be new.
A list of what all I changed for the bottom end:
Crank
Counterbalance
Rotary valve
RV shaft
All seals
Once everything arrived, I began reassembly.
I made sure to align the marks on both the counter balance and the crank. Once they were sitting in their spots, I rotated the Rotary valve shaft to ensure everything was turning freely. I then sealed up the crankcase using a small bead of the Loctite 518 sealant as the manual calls for and moved to the pistons.
The top half of the motor went together really smoothly, I was very careful in making sure everything was lined up correctly, soaked in assembly lube, and began to slide the jugs back into place. I used a small amount of gray marine RTV around both sides of the gasket material and torqued the cylinders back down to specs described in the seadoo shop manual. The rest was pretty straightforward from that point until timing.
I was then ready to reinstall the new RV and its cover. After following the manuals instructions, I marked the motor where both 147 and 65 degrees were.
The plate aligned perfectly with the new marks.
I then reattached the RV cover and rotated the PTO to make sure everything rotated freely.
The next few things such as the exhaust header, rave valves (that were shaved to match the .5mm oversize piston), and stator cover were all a breeze to reinstall. I lowered the motor back into its spot and began plumbing and wiring. That afternoon I was ready to hookup the candoo and reset TPS. After resetting TPS I started the ski on the trailer. Once I turned on the hose pipe water I noticed two very strong streams of water coming from injector holes of both cylinders. I turned off the ski and pulled both injectors only to find that BOTH jugs had cracks around the injector holes. Fortunaltey they were only spraying on the outside and no water had gone in to the motor. I have no clue how I didn't notice them when I put it back together but they were there! I can only wonder if the machine shop used these holes to hold the jugs while they were working on them.
I ended up pulling the motor back out again and removing the jugs. I figured it would be best so that I could make sure gasket material was scraped off and that everything was realigned during reassembly. I took them and had them welded which took a few days after I dropped them off. When I got them back I painted a small layer of marine JB weld on the inside of the jug around the crack just to play it on the safe side. I waited a few days and reassembled the motor again. I dropped the motor back in and started the motor back up. It seemed to be running great so I decided to put it back in the water. I slowly putted around with the seats off to watch and see if there were any leaks/issues that may stand out. I gave it a little bit of throttle and the engine came to a halt. Before trying to start it back up, I checked the oil lines and began to worry that it may not be pumping. Hard to tell if it was, the water was rough and not much room to move around. I decided to paddle back to the dock and order a new oil pump just to be safe. Once the new oil pump arrived I put it on, aligned the marks, and bled the lines. I backed it into the water while it was on the trailer to check for idle RPM and found that now it was only running on one cylinder. I swapped both of the plugs and found that one of the new spark plugs I had purchased was already no good. No signs of anything wrong on the plug itself but no fire. I got a new plug and changed it. Bingo! First time it had run so smoothly in a long time. I left idle at around 1600 for a bit but slowly backed it down to 1500. I drove it around in front of our dock for about 30-45 minutes being careful to mind break in procedures. During this time the ski ran the best it ever has! I pulled up to the dock after about 25 minutes to let it idle for about 5 minutes and noticed the 12v low light was on again. Great. I knew the battery was fine and had over 12 volts on it before I got on for the ride. I decided to see if I could run it around for a bit at higher RPM to see if it would go away. As soon as I got far enough out I couldn't paddle back easily (smart move) the motor stopped again. I tried to restart it but it seemed as if it had no spark. The battery seemed fine and was able to turn the motor over with no issues. After waiting for a family member to come tow me back, we pulled the ski on to the lift and tried to restart it. No luck. Engine turns over smoothly but no fire. Plugs also seemed fine but I put two new ones in just for kicks. No dice. We ended up draining the battery too low to turn over the motor so I went to buy a new one with hopes that the old one (a year old PC625 that was even brought indoors for winter and charged) was faulty. I installed the new battery, siphoned all the gas out, refilled it with fresh non-ethanol gas, and replaced both plugs again. I tried to start it and yet again. NO DICE. I checked the stator windings and found no abnormalities with checking resistances between phases and none of them were grounded out. I checked the rectifier diodes as well as checking reverse bias. Everything seems good! I pulled the plugs and checked for spark and it is definitely getting fire on both cylinders. There is some white smoke that comes from the vents of the intake air box after about 5-10. seconds of turning the starter over. I can also pull the throttle in a little bit while starting ( and I mean a very small amount) and it stumbles very slightly and then immediately dies off. I have checked fuel pressure and everything was within specs of the manual. Does anyone have any ideas of what would be causing this issue? I have a lot of money wrapped up in this rebuild and not a clue as to what is going on. If anyone also has any insight as to why the engine may have failed in the first place I would love to know! I have money on the oil pump but I'm not sure.
I have tried:
checking/replacing fuses
new plugs
Trying to run ski on one cylinder (swapping back and forth)
new battery
fresh gas
adjusting idle screw
I also cleaned the injectors a while back right before I started the rebuild.
I took the cylinder jugs to a local machine shop who has worked on these motors before and he was able to bore them out .5mm oversize. I decided to go with a complete engine kit to replace the seals on the crank and bearings since I was already knee deep in this project. I then ordered a complete engine rebuild kit from WSM and began tearing the bottom crankcase down. Once open I made note of a few other components and ordered them all so that they would all be new.
A list of what all I changed for the bottom end:
Crank
Counterbalance
Rotary valve
RV shaft
All seals
Once everything arrived, I began reassembly.
I made sure to align the marks on both the counter balance and the crank. Once they were sitting in their spots, I rotated the Rotary valve shaft to ensure everything was turning freely. I then sealed up the crankcase using a small bead of the Loctite 518 sealant as the manual calls for and moved to the pistons.
The top half of the motor went together really smoothly, I was very careful in making sure everything was lined up correctly, soaked in assembly lube, and began to slide the jugs back into place. I used a small amount of gray marine RTV around both sides of the gasket material and torqued the cylinders back down to specs described in the seadoo shop manual. The rest was pretty straightforward from that point until timing.
I was then ready to reinstall the new RV and its cover. After following the manuals instructions, I marked the motor where both 147 and 65 degrees were.
The plate aligned perfectly with the new marks.
I then reattached the RV cover and rotated the PTO to make sure everything rotated freely.
The next few things such as the exhaust header, rave valves (that were shaved to match the .5mm oversize piston), and stator cover were all a breeze to reinstall. I lowered the motor back into its spot and began plumbing and wiring. That afternoon I was ready to hookup the candoo and reset TPS. After resetting TPS I started the ski on the trailer. Once I turned on the hose pipe water I noticed two very strong streams of water coming from injector holes of both cylinders. I turned off the ski and pulled both injectors only to find that BOTH jugs had cracks around the injector holes. Fortunaltey they were only spraying on the outside and no water had gone in to the motor. I have no clue how I didn't notice them when I put it back together but they were there! I can only wonder if the machine shop used these holes to hold the jugs while they were working on them.
I ended up pulling the motor back out again and removing the jugs. I figured it would be best so that I could make sure gasket material was scraped off and that everything was realigned during reassembly. I took them and had them welded which took a few days after I dropped them off. When I got them back I painted a small layer of marine JB weld on the inside of the jug around the crack just to play it on the safe side. I waited a few days and reassembled the motor again. I dropped the motor back in and started the motor back up. It seemed to be running great so I decided to put it back in the water. I slowly putted around with the seats off to watch and see if there were any leaks/issues that may stand out. I gave it a little bit of throttle and the engine came to a halt. Before trying to start it back up, I checked the oil lines and began to worry that it may not be pumping. Hard to tell if it was, the water was rough and not much room to move around. I decided to paddle back to the dock and order a new oil pump just to be safe. Once the new oil pump arrived I put it on, aligned the marks, and bled the lines. I backed it into the water while it was on the trailer to check for idle RPM and found that now it was only running on one cylinder. I swapped both of the plugs and found that one of the new spark plugs I had purchased was already no good. No signs of anything wrong on the plug itself but no fire. I got a new plug and changed it. Bingo! First time it had run so smoothly in a long time. I left idle at around 1600 for a bit but slowly backed it down to 1500. I drove it around in front of our dock for about 30-45 minutes being careful to mind break in procedures. During this time the ski ran the best it ever has! I pulled up to the dock after about 25 minutes to let it idle for about 5 minutes and noticed the 12v low light was on again. Great. I knew the battery was fine and had over 12 volts on it before I got on for the ride. I decided to see if I could run it around for a bit at higher RPM to see if it would go away. As soon as I got far enough out I couldn't paddle back easily (smart move) the motor stopped again. I tried to restart it but it seemed as if it had no spark. The battery seemed fine and was able to turn the motor over with no issues. After waiting for a family member to come tow me back, we pulled the ski on to the lift and tried to restart it. No luck. Engine turns over smoothly but no fire. Plugs also seemed fine but I put two new ones in just for kicks. No dice. We ended up draining the battery too low to turn over the motor so I went to buy a new one with hopes that the old one (a year old PC625 that was even brought indoors for winter and charged) was faulty. I installed the new battery, siphoned all the gas out, refilled it with fresh non-ethanol gas, and replaced both plugs again. I tried to start it and yet again. NO DICE. I checked the stator windings and found no abnormalities with checking resistances between phases and none of them were grounded out. I checked the rectifier diodes as well as checking reverse bias. Everything seems good! I pulled the plugs and checked for spark and it is definitely getting fire on both cylinders. There is some white smoke that comes from the vents of the intake air box after about 5-10. seconds of turning the starter over. I can also pull the throttle in a little bit while starting ( and I mean a very small amount) and it stumbles very slightly and then immediately dies off. I have checked fuel pressure and everything was within specs of the manual. Does anyone have any ideas of what would be causing this issue? I have a lot of money wrapped up in this rebuild and not a clue as to what is going on. If anyone also has any insight as to why the engine may have failed in the first place I would love to know! I have money on the oil pump but I'm not sure.
I have tried:
checking/replacing fuses
new plugs
Trying to run ski on one cylinder (swapping back and forth)
new battery
fresh gas
adjusting idle screw
I also cleaned the injectors a while back right before I started the rebuild.
