94’ XP New Engine

[Spiffy1996]

So picked up two 94’ XP’s earlier this season for a steal. I got two running skis, double trailer, a spare hull, a complete spare engine, and a ton of spare parts. They were running but needed some love. Both skis had around 120-130 PSI compression in the cylinders, I know not ideal PSI but should be enough to have a lil fun for the season. Got them sorted after throwing the basics at them (new fuel, fuel lines, filters, batteries, spark plugs, etc) and a few test and tune runs and took them out a handful of times after. Well last week the one went down on power after a half hour or so of riding and once it started losing power I slowed down to figure out why and it shut off and wouldn’t fire back up. Got it home and compression was around 115 PSI on the PTO cylinder and 85 PSI on the magneto side. Pulled the motor out and discovered the oil injection pump had failed. Fortunately I had the spare engine to put in to make it the rest of the season. Compression tested that spare motor as it was a “good engine” by word of mouth by the seller so wanted to see before I took all that time motor swapping to find it has low compression too. Found out the spare motor has 130-135 PSI on the cylinders so again not perfect but rideable. This motor I am going to convert to premix and delete the oil injection pump and probably do the same with the other ski as well once I successfully delete this ski. Just curious for those that have deleted the oil injection pump did you guys take out the factory oil tank and put a smaller one in since I know you need to keep an oil reservoir to lube the rotary valve or just keep the factory tank? Those that kept the factory tank what did you do with the line that would supply the injection pump? I’m assuming just Tee it into the line that goes to the rotary valve?

More importantly I have a problem with the stator on the new motor I’m dropping in. The old motor had five wires coming from the stator and this new one only has four? The wire I’m missing on the new motor is the white one. I’m assuming I can just pull the fly wheels and swap the stators over from one unit to the next? They’re both 657x motors so not sure why I couldn’t do that?

Any input or information is greatly appreciated.

 

[AKnarrowback]

I can't answer the wire question since I'm out on a job away from my machine for a week. I run a 94 xp as well.

You can remove the oil injection and premix. Just make sure the two smaller lines from the pump to the intake are blocked off air tight and mix your gas. The easiest thing to do for the rotary valve shaft is to leave the oil injection tank in place with the feed lines to the RV shaft chamber and keep enough oil in the tank to fill both the lines. Just an observation that I can't prove but I would not run a synthetic oil in the rv chamber. The rv shaft seals wear out and can leak oil into the case leading to smokey starts. This smoking is something I never saw out if a rotax RV motor until synthetic oils came on the scene. I have run RV motors in sleds for 35 years and worked with seadoos in the 89-95 era using the old mineral oil skidoo sold for decades and never saw the smoke screen I see from these motors using synthetic oil. For rave or power valves you need the cleaner burning synthetic, but (in my opinion) synthetics fail the RV seal test.

You have the 657X motor in those machines, it is not 100% interchangeable with the regular 650 motor so double check any parts you might order for them. They only used the 657x for a short time, not because it was a bad motor, but they simply came out with the 720 and the x was phased out.

 

[Spiffy1996]

I can't answer the wire question since I'm out on a job away from my machine for a week. I run a 94 xp as well.

You can remove the oil injection and premix. Just make sure the two smaller lines from the pump to the intake are blocked off air tight and mix your gas. The easiest thing to do for the rotary valve shaft is to leave the oil injection tank in place with the feed lines to the RV shaft chamber and keep enough oil in the tank to fill both the lines. Just an observation that I can't prove but I would not run a synthetic oil in the rv chamber. The rv shaft seals wear out and can leak oil into the case leading to smokey starts. This smoking is something I never saw out if a rotax RV motor until synthetic oils came on the scene. I have run RV motors in sleds for 35 years and worked with seadoos in the 89-95 era using the old mineral oil skidoo sold for decades and never saw the smoke screen I see from these motors using synthetic oil. For rave or power valves you need the cleaner burning synthetic, but (in my opinion) synthetics fail the RV seal test.

You have the 657X motor in those machines, it is not 100% interchangeable with the regular 650 motor so double check any parts you might order for them. They only used the 657x for a short time, not because it was a bad motor, but they simply came out with the 720 and the x was phased out.

Roger that, got the new engine all ready to be stuck back in and see what we can get out of it for the remainder of the season, waiting on some carb gaskets as the kit I bought for some reason didn’t have em, guessing they just never made it in the package cause I bought a total seal kit. Now the other ski is acting up...but that’s a story for another tread. Thanks for the info! I actually wound up just taking off the stators and swapping them over along with the wiring harnesses for them. They looked IDENTICAL and were the same size and dimensions and make ups in every way except the one had a 5 wire harness and the other had a 4.