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  1. #1

    thanks for all the info..helped me in every step putting a jet ski together

    just would like to take the time to thanks all folks on here posting their issues and fixes, i bought a 750 sl polaris for 500 with trailer, it ran for about 10 minutes then i knew something wasnt right , took the spark plugs out turned engine over and metal chunks come flying out of hole. i was bummed big time ,luckily i found another one for 200.00 with a bad starter , by this time i had read tons of info on this forum , i knew exactly what i needed to check to see if this was worth my money, after all i was only after the engine, after checking several things i decided to buy this thing. pulled the skis side by side and dug in , a little agrevating at some points , but not bad ..put battery in the 200 buck ski and starter wasnt bad ,the bendix was , so more work the tank needs to come out , and in that process noticed the fuel lines deteriated, more the other ski had been up dated so i had the parts to fix it.. swapped bendix and now it engaged. now its time to fire this thing then no fire , well not a problem i have a stator so removed all rquired parts to get to the stator ..installed parts from other ski . by this time im pretty much had my feel of working on this ski . i primed tthe carbs with premix and she fired ...put my tools up for the night... 8 hrs of learning as u go wears me sunday morning finished putting her back together and looking over things , put a new fuse in the black box and mfd worked great. time to ride ...not... it started storming , my luck a break in the weather , just wanted to test the power for a few to see what else i need to work on...finally out on the water she was smooth and strong and no hesitations , but top speed 30 mph...not again problem home and i remembered the 2 jetskis had 2 totally different plugs in them , so i did a look up and what do u know in had the wrong ones in, so got the right ones and put them in next day 50.8 mph on the gauge..much better, i checked the cylinder heads with the feel method none were scorthing but mag cylinder was noticabley warmer , i had already read about the fuel pump and auto cock , so i already ordered the kit...installed today and mag cylinder running at 140 to 143, center at 130 to 135 as well as the rear cylinder , not sure about the temp difference on cylinders but she ran flawlessly for over an hour, i had temp sensor hooked to mag cylinder the whole time i was riding and checking it it many times at low speeds and after full throttle.. long story short 500.00 1st ski and 200.00 second ski made a kick but 700 dollar ski , plus fuel pump 745.00 equals happy rider for info i recieved here saved me hours of time, yes i would have got it , but goin in with knowlegde is a much better deal than blind ..all this took place in 3 thanks again

  2. #2
    Click avatar for tech links/info K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada
    Fast work!

    Somewhere in there did you clean/rebuild those carburetors?

    Check the jet pump bearings and seals?

  3. #3
    im going to rebuild the set off one in the next few weeks, i did take on some water ,not alot though. so yes seal and bearings aere next on the list. but from the way everything looks all cylinders are burning just right , maybe carbs have something to do with the 10 to 15 degree temp difference, like i said never even worked on a jet ski before. thanks for the link

  4. #4
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    Yeah... carbs/fueling can cause temp differences between cylinders. Usually because the hotter cylinder is running lean. Too lean and it melts down... so be sure to get on that. There shouldn't be a noticeable difference in temp when you touch the cylinder heads on a running engine. Should be able to hold your fingers on the heads for 2-3 seconds before it gets too hot. Definitely shouldn't be any water sizzling anywhere... that would be way too hot... and if you see water sizzling, don't touch it.

    A common water leak point is the through-hull driveshaft seals. It's the thing on the inside of the hull that the ds slides through on it's way to the jet pump. It's connected to the hull via hose and clamps. Pull the ds out (after you pulled the jet pump out), then undo hose clamps and wiggle it out. You will see a seal on each end. These are what get old and worn and let water leak past. You can pry these out and replace. See the Polaris PWC Info bank (link in K447's signature) for more details.

    While you have the jet pump out, pull the impeller off (you will need impeller removal tool... $10 at overtons) and make sure the seals there are good and there is no water getting into the bearings. This can be rebuilt also... 2 bearings, 2 seals and an O-ring... kits are available online.

    Good luck!

  5. #5
    the temp numbers i mentioned 140 130 were taken with my multi meter with temp sensor on top of head it was at various speeds , i think i read somewhere that 143 is the thermostat opening point? is this correct?...heck i with my lack of experience in jet skis , im thinking i will take 3 heat sensors(made for gas rc cars) put on each head and be able to moniter temps ..yeah im a bit paranoid.. the way i see it elavated tempature is your first warning sign of engine failer

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