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  1. #1

    Rebuild Advise Needed

    I've been reading these forums, and soaking up a lot of great information. This is my first jet ski, and I want to have a nice and reliable play toy for my family. It's a 93 Polaris SL 650, that I got from a buddy who let it sit for about 3 years. He told me that it was running when he parked it. (he is a boat mechanic) I am a pretty decent shade tree mechanic myself, having rebuilt many motors, and a few transmissions, so this is not going to be hard for me. I have already gutted the hull of the engine, pump, exhaust, and fuel tank. I like to know that everything is done right, and this will be like a new ski when I get it done. I do have some questions since this is my first marine engine.
    1. Is there a special type of fuel lines? The reason I ask, is because the ones that I pulled out of the tank, were like molten rubber. Almost in liquid form! I'll be totally replacing the hoses, filters, screens, ect., including rebuilding the carbs. And I will be getting a new triple outlet fuel pump, mounted low in the hull. Right?
    2. What should I do if the pistons, and cylinder walls look OK? I didn't check compression, and the crank moves freely. Should I hone the walls, and check the ring gap, or maybe re-ring the pistons? One thing to mention. When I pulled the reed valves, the crank case was full of oil/water. I haven't opened the case to check on the crank and bearings yet, but I will. I just hope it was more oil than water.
    3. I will also be blocking off the oil pump system, and running pre-mix.
    4. The jet pump from what I've read, is not the best. I understand that a newer long pump id better, but is it really worth it? I'm not looking for a drag ski, or top end speed. (yet...) I might get hooked, and look for a bigger ski for myself later on. And I haven't pulled the pump apart to check everything out yet, but it won't turn but about a few inches. Just dirty/ gummed up I hope.
    I'm just looking for your recommendations on what I need to do while it is all apart. I don't have a lot of money to spend on it so keep that in mind. And if you can recommend some links for parts, I'd appreciate that too.
    Should I do a build up thread on this?

  2. #2
    I have been working n it a little this evening, and here's what I've come across. I pulled the coolant flushing hoses off of the bottom of the motor, and one was clogged with sand. The other one about half clogged. the crankcase is full of oil/water, but I didn't see hardly any rust. After looking at the piston tops, I noticed that the mag piston has a 25 stamped on it. So I guess somebody has been in this motor before. And there was a date and initials on the inside of the hull 12/95.
    I tried to get the drive shaft coupler off of the end of the crankshaft, but it wouldn't budge. Then I tried to pull the flywheel off. My puller only has 2 bolts for this thread pitch, so I'll have to wait until I can go to the hardware store, and get another to match.
    So I'm at a sticking point tonight. I started to spray paint the inside of the hull, until I ran out of paint.
    Any suggestions on getting that drive shaft coupler off?

  3. #3
    Race, wreck, repeat delagem's Avatar
    Join Date
    Aug 2006
    Homer, NY
    I understand that the coupler is a LOT easier to pull off when the motor is in the ski. I found this out the hard way. Finally got mine with the use of MAPP gas and O2, got the thing cherry red (I was changing the crank seals anyways). Maybe you can have somebody hold the motor while you use a pipe wrench and cheater bar; I did this with a floor jack to hold the motor still. See pic.

    You'll need to lock the crank in place. Some people put a couple of feet of rope in the PTO cylinder to hold it in place, a clever suggestion from Beerdart was to flip the head over, and the raised dome contacts the piston. I happened to have a nice scrap of oak of the right thickness, I just rounded the corners a little bit and put it in the cylinder, and bolted the head back down.

    I like Tygon fuel hose, but some people have been saying it's too soft. Not sure. I run it on every non-fuel injected motorcycle I own, never had any problems. You'll get some other suggestions shortly.

    I hate that cheap blue fuel line that all the dealers sell, from Parts Unlimited! Had a big fire on my John Deere from that junk! Stuff gets brittle, and gooey, and the hose fell off while I was mowing my lawn, and the fuel tap was directly above the muffler! D'oh! Good thing I have a dozen fire extinguishers around the house and garage.....
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  4. #4
    I'm a newbie as well and I got this 95 Slt750 that was dumped off in my neighborhood around New Years! I found this forum and the guys here were a great help considering this is my first time too, working on a jetski. I've rebuild car/motorcycle engines and presently rebuilding my 140 hp Mercruiser engine for my Bayliner. Like all projects I find it helpful to get a Repair Manual specific to your jetski and study it! If you get stuck then call on the forum!! I replaced my topend (std) and put on some Vortex FA's. I didn't want to mess with the jetting and basically kept it stock. On the advise of the forum, I removed the oil injection system and I'm running Premix 40:1. The fuel pump was also upgraded to a triple feeder! The fuel lines are marine grade. I just wanted to spend the least amount of money so that I can take this thing on the water but I wanted to correct the faults that others experienced with this model! Later, I found out that the jetpump bearings were frozen and ended up replacing the whole unit for a extended pump with a 12/17 prop, a R&D grate and ride plate. That's it!! Jetski runs great!! I ran into a few problems first time out but that was human error!! It really depends how far you want to go and how much you want to spend! Sky's the limit! Goodluck!!

  5. #5
    Thanks for the replys fellas. I have been studying my manual that I got for the ski. Tomorrow, I will try to get the things that I need to pull the rest of the engine apart, and start cleaning parts.

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