93 XP Project Ski

[CodyT]

Picked up my first ski on craigslist about 3 weeks ago. As it sat the guy told me it needed "a new CDI box" which died after it wouldn't restart and they jumped it...
He also said that the top end had just been rebuilt. I took his word for it and hauled the dirty thing home.

Got a shop manual for it and started digging in. Ordered MPEM and started to go through wiring. Instantly I knew something was up, the lanyard was bypassed and half of the wiring was totally wrong along with it having regular steel nuts and bolts everywhere. Fixed all of the wiring and checked resistance to insure there were no shorts. Put my mpem in but got NOTHING when pushing the start button, figured out the button was bad and replaced.

Ski fires right up and sounds pretty smooth except for foamy oily mixture dumping out of the nozzle but I didn't think much of it. Sea trials revealed full and sustained power with great acceleration. It wouldn't idle but I believe that i need to turn in the idle screw since it drops below spec RPM when idilng then shuts down. VTS isn't working, I hear the motor turning with a "click click click." That turned out to be the goofy plastic drive shaft in the module was cracked. Plastic welded the crack, drilled shaft, and put a pin through it... Repaired.

I'm on the Delaware River letting it rip and feeling good that I haven't had to put a whole lot into the ski. I'm opening and closing the throttle while styling and skipping wakes... RPMs wont go above about 5700. Cooled down and stopped to have a look, throttle cable had popped out of the holder by the thumb actuator. Popped it back it but now the starter wont crank! Gauges are flickering so I know MPEM is signaling, it has to be the solenoid. Still on the water and drifting I pull the cover and electrical box. Smacking the solenoid with a wrench makes it crank but the engine wants to turn over so I only get a moment or two of cranking. Exhaust has water in it and I can't get a good enough crank to blow it out... Pinch off the water intake and proceed to do my best to get a good crank until the battery drained. Signaled for assistance on the VHF and actually got a buddy fishing in the bay. 2.5 hrs later he arrives to tow me in, was so beat from keeping it up-right in the waves that I had hung out my diver down flag and floated behind the ski.

Got home, pulled the plugs and put battery on charge. Next morning I went to flush it out (solenoid works just fine now, go fig) and noticed the head bolt right next to the water intake is oily and foaming. Aww shi*! Attempt to tighten revealed that the threads are gone. At this point I was a little unsure of the future of this ski and I. Towed it to the old man's house to pull the cover and head.

:dupe: First, 5 heli-coils have been installed in the threads between the 2 cylinders. Aft cylinder sleeve o-ring is blown out and some a-hole had decided to put epoxy into the aft bolt holes i suppose in some attempt to keep the bolts in place since the heli-coils were poorly installed. Attempting to compress the liquid damaged the thread walls.

So here I am. It looks like all of this can be repaired properly and since I believe in repairs instead of R&R I plan on removing the coils, tapping whats left of the walls, locking in an aluminum bolt, and drilling/ tapping that for fresh threads. Obviously I need a gasket kit, solenoid, and new spark plugs.

My point here is actually a question. Is there anything that I should be doing while I'm in the top end of this engine in order to reinforce the aluminum since someone obviously didn't know that FT doesn't work on soft metal, or simple things that may help me in the long run. The rest of the engine appears to be in great shape so I'm also interested in power-adders. I do realize that I'm playing with a machine that is about 18yrs old but it is a project so I'm not going to be getting rid of it...

Oh. Also, I've reupholstered the seat and I'm prepping it for a paint job.

Thanks for readin
Cody

 

[CodyT]

Top end finished. Ended up pulling the bad heili-coils on the aft jug, cleaning them out, and sinking stainless all thread studs in Marine-Tex. I was surprised that it actually did what the manufacturer said it could. The studs held amazingly well... Torqued everything to spec except for the three new studs that i set at 19ft/lbs instead of 17 just in case the material expanded when it got warm. I also compressed an aluminum and hard nylon washer under the cap nut just to be sure.

Engine testing, beautiful... Got it warm, checked my seals, and let-er-rip. Top end RMS are now at about 6700. I was able to keep up with a much newer ski. It was a SeaDoo but I couldn't make out which type, still made me feel like I actually had something lol.

VTS is malfunctioning again, relays are clicking but the motor won't turn. I've misplaced my meter so I haven't been able to check to see if I'm getting 12v when the relays close. I was in the electrical box to replace the solenoid and all wiring appears okay. Either way I'm scrapping that whole goofy system. I'm going to mount a linear actuator up near where the OE equipment sat and use the OE buttons to operate the actuator which has its own relays and limits.

I'm concerned about engine temps. I don't like relying on a buzzer and temp sensor to tell me when my engine is about to melt. I'm considering replacing the stock sensor with a gauge and putting a resistor on the line so the MPEM thinks all is well. I'd also like to put a flow sensor on the oil line... I watch my gauges constantly so I'm sure to see problems before I can destroy anything. Damn don't the newer skis come with all of this stuff?

Please give me your input if any of this sounds dumb or if I should be doing things differently.

Thanks
Cody

 

[ski-d00]

Nice work! You are doing a great job.

I have lots of left over parts sitting in boxes from a couple 93 XPs that I parted out years ago, including the VTS and 657 engine parts, if you need cheap parts. I cut the hulls up in little pieces and put in the trash, what a mess.

 

[CodyT]

Thanks for the input. I'm looking at a couple different things to do at the end of the season. Fuel sender isn't working, I believe that the float is no longer... well floating and the old gray fuel lines need to go. I want to pull the pump housing and redo all of the seals and wear ring as well. VTS started working again and I'm betting the motor had somehow jammed as it started working after I left it off and let it bounce around in the bilge for a while lol.

Took some friends tubing which worked out nicely but out a bit more stress on the engine than I'd like.

Now for questions... Not much fresh water where I live so I'm always out in the DE river and bay. I flush and wash after every run but would it be a good idea to mount some zinc anodes by the nozzle and shaft? Continuing with that thought I have a problem with cavitation when I skip over the chop. Is there a grate that I should be running for this kind of water? Last thing, is there a such thing as an acceleration limiter? What I'm talking about is a device that monitors the RPMs and will drop out the coil if the engine accelerates too quickly, cavitation. I know there is a overall rev limiter but I don't like the engine surging when it looses suction for a split second even though I never let it hit the limit.

I can make the acceleration limiter with some simple electronics but want to see if there is already a product out there. It would drop the spark if the engine speed changes quicker than it would under normal acceleration.