06-09-2012, 09:46 AM #1
Cutting back your plug wires a 1/4"
I'm working on the Pro785 today before I take it out and decided to cut back the plug wires a 1/4" to reveal new copper on the wires. I found the end to be green with corrosion. Thats no good. So I cleaned up the plug boots first and checked them closely for anything wrong. Looked ok to re-use. I found corrosion on all 3 wire ends. it traveled about an 1/8" back on each one..
That length is exactly how long the screw in tip is inside the boot!. I have been running it like since I got the ski running. It always starts, never stalls, idles good too. So I know its not a HUGE deal but it needed to be taken care of.
Once back together, i fired it up and was surprised to "feel" a difference on the throttle response. Whoa! touchy touchy touchy!!!! its better than before for sure! I cant wait to give her a rip now! She should Jump out of the water now. It was already pretty good before I thought.. Maybe even pick up a few more RPMS from getting ALL the spark instead of most of it before.
I made a video of what I'm talking about.. check it out.. well worth taking the time to do this. especially if the ski has never had it done before. I bet salt water skis need it even more than fresh water skis.. Anyone else find any green on thier plug wire ends?
06-09-2012, 11:18 AM #2
I had to do this to my '98 before it burnt down a piston. It was acting like it was loading up and misfiring so I tried the simple thing first. The wires were pretty green too. Worked like a charm.
06-09-2012, 05:24 PM #3
Did you feel any improvement on the water? I didn't get a chance to run it yet. Had to go see Mom at the hospital..maybe tomm morning I can see if there is any difference. Hopefully my tach numbers will go up. 7400 (before trimming the wires) so far after the center was turned in an 1/16th-1/8th gained 140. Wash was the same after but gained some rpms.. It revs to 7990 now (higher than before trimming) if you goose it on the trailer. ...engines under load and at high rpm need a sharp spark to fire . we'll see what happens. Cleaned the piston tops to get a new wash pattern too.
I may tie back the valves all the way open. they dont look they are working properly. i should of seen the valves opening all the way and they looked like they weren't. I need gas valves.
06-12-2012, 09:37 AM #4
I don't think you're going to get ~600 RPM out of clipping the wires. It sort of either fires or it doesnt. Mine wouldn't even get up on a plane before I trimmed them because it was only firing on 2 cylinders.
06-12-2012, 08:16 PM #5
We dont have to worry about the rpm gain. that motor is coming out! we'll see what the next one does. if it doesnt act like its suppose too,, then its the pipes being too short for the correct pressure wave. i cant think of anything else it could be. possibly the valves arent opening all the way at wot. kinda hard to look down as your flying around the lake!. Ill test them before i pull the motor and check movement on them. They are not dirty(stem and blade) so thats not causing a interference/ hard moving situation. who knows. could be the timing is off a little. really though, who cares, as long as your having fun, that to me is all that matters along with being reliable.
06-13-2012, 01:19 PM #6
06-13-2012, 03:02 PM #7
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- Milwaukee WI
06-13-2012, 06:27 PM #8
I could rig my my Gopro camera in the engine compartment and watch the video!. Maybe this new engine once in and I can try that. It has the suction cup mount so it could be done with the seat off while riding. Good news, I went to my local polaris junkyard and picked up a polaris 750 R and D grate for the SLX for 40.00, a PITOT tube for the Pro! and,,,all 6 gaskets for the reed cages for the new motor today! woohoo.. he gave me the pitot tube assembly for free and got all 6 gaskets for 8.00 buckeroos. what a deal.
And, I ordered all the rings for the slx, new piston pins and an upper gasket kit. Bryan, I think you had a good idea on the porting.. I'll hold off on that and lets get this baby together! I have a good jug for the one that was cracked at the port and the R and D grate should keep her planted! I just need some days off to start all this wrenching!!!!
And, as we speak, i'm stripping the last 3 big pipes for the slx and bought the paint too so they will be done pretty soon!!!
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