1996 ZXI 900 limited to ~6500 RPM after some usage - PWC Forum: The best hang-out for Personal WaterCraft enthusiasts
 
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post #1 of 7 (permalink) Old 06-10-2019, 05:24 PM Thread Starter
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1996 ZXI 900 limited to ~6500 RPM after some usage

Hello there! Just throwing this all out there to spur some discussion while I reload the parts cannon for my ski.

I've got a 1996 ZXI 900 that I've put a fair amount of time into and it's running pretty much great. Sometimes. Iv'e rebuilt the carbs, eliminated the choke in favor of a primer kit.. It's got a new crank, seals, bored over 1.5mm cylinders, new rings and pistons. It's a fully rebuilt motor.

When I got the ski there was evidence of standing water in the stator housing. Rather than replace the stator I cleaned it best I could and ran it. It produces charging voltage and runs the ski. Trim box is fully rebuilt with new cables and seals. Trim works great. Jet pump is all new with a 1 season old Solas impeller, bearings, shaft, wear ring, everything.

The problem is, and I don't know if it's a heat soak issue, but after say 15 or so minutes of just full throttle it seems to drop a cylinder or cut back on power. It'll get up on a plane but barely, while being limited to around 6500 rpm. It has the oil pump delete and, like an idiot, I removed the front cooler cover too off the stator cover at the same time. I've been able to find the cooler cover in my parts pile and new orings, and that's all back together now while I wait for my new stator to arrive. I guess the ultimate question here is, can heat soak cause the stator if it's weak or damaged to crap out partially? Pisser water flow is excellent, with no signs of any gasses being pushed out.
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post #2 of 7 (permalink) Old 06-11-2019, 06:03 AM
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You were fine with the stator cover removed. I believe it was just to cool the oil pump drive bearings. When it does this, have you reached down to feel the water temp ? It is poss the by removing the choke, it created a slight lean issue, so I would give the high speed jets a little more out. Maybe 1/16 of a turn, but that wont fix your issue.
Have you checked spark on all 3 when this happens ? Could be a bad plug wire. Might try trimming them back about 1/2" and see if that helps.
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post #3 of 7 (permalink) Old 06-11-2019, 05:23 PM Thread Starter
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Quote:
Originally Posted by rodsatheart View Post
You were fine with the stator cover removed. I believe it was just to cool the oil pump drive bearings. When it does this, have you reached down to feel the water temp ? It is poss the by removing the choke, it created a slight lean issue, so I would give the high speed jets a little more out. Maybe 1/16 of a turn, but that wont fix your issue.
Have you checked spark on all 3 when this happens ? Could be a bad plug wire. Might try trimming them back about 1/2" and see if that helps.
Wouldn't turning the screws OUT allow more air in, thus making it leaner?

I haven't been able to check spark as it happens due to the logistics of where I ride.. it's a very public multi-use ocean-attached bay (read: It gets choppy) with a simple loading ramp and 15 minute dock. I can't take my 2 stroke into any lakes around here due to CA regulations. I did trim some off the wires last season but I'll unscrew them again and check. I may need new wires/caps.

The new coil arrived and it ohm's out perfectly so I'll eliminate that possibility and swap it today. I'll be back out on the bay sunday so if it acts up again after I once-over the electrical system I'll reach down and feel the water temp out of the pisser. How hot is too hot? Not sure how warm I should expect the water to get with 66 degree bay water temp

Last edited by HannsGruber; 06-11-2019 at 05:29 PM.
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post #4 of 7 (permalink) Old 06-12-2019, 05:33 AM
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The mixture screws meter fuel not air on these carbs.
Ya, Calif. regulations have gotten super strict because of muscles. My brother just goes to Pyramid and keeps the security lock on. To much of a pain to do different lakes.
I have had the wires break internally and only gotten sporadic spark. Get frustrating. Check it at home, good, get to the lake, dropped a cyl. Changed the wires with solid core from the parts store, and good to go. It's a pain to deal with the box though.
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post #5 of 7 (permalink) Old 06-17-2019, 12:21 AM Thread Starter
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Well, it's fixed! The new stator had an issue so I put the old back in, but I did keep the cooling plate on. I also installed new spark plugs and wires, though I couldn't find any solid core locally on short notice so I went with the next best thing, some Accel Super Stock Spiral Core wire. 500ohm/ft but when you run resistor free plug ends it all works out to ehhhhhbouts the same overall ohm's


Here's some gopro footage from today. I've got a few hours worth but this sort of shows how hard it is to really cruise where I ride. Early AM is great it's like glass. At least it sounds good with with that TDR waterbox.

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post #6 of 7 (permalink) Old 06-17-2019, 05:29 AM
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Does sound nice with the tdr. Glad you figured out to use non resistor caps with resistor type wire. The wire I got was actually a universal set for a tractor. I'll see if I still have the box laying around.
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post #7 of 7 (permalink) Old 06-17-2019, 01:30 PM Thread Starter
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No lie, I did look at Tractor Supply too. They had some options for some old Ford tractors but some reviews were complaining that the "solid core" they were selling actually had 1,000 ohm/ft.

I'll probably, now that it's running well, order a spool of solid core from Ebay and keep it on a top shelf for the future.
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