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Thread: Sl 750 advice

  1. #1

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    Sl 750 advice

    I have a 95 sl 750 that I bought new. I hav no mods and never had any problems with it until the wife flipped it and since it feels that its not getting enough fuel. it has a hard time idling, and will only run at wot if the choke is slightly pulled. I am guessing that it is time to rebuild the carbs, or should i be looking at something else for the problem?

    Here is my question, since i have never rebuilt carbs, is there someone here that can handle this? Also, i would like some more performance, what are the first components that I should buy? Reeds? pipe? ride plate?

    thanks.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome back

    If the engine ingested water, you could have internal damage.

    Have you checked cylinder compression, and crank index?

    First diagnose the current problem(s), hopefully get it running properly, then you can review the potential upgrade options.

    Carburetor rebuilds are really not that hard to do, and the information you need is available around here.

    If you really want someone else to do it for you, there are a few members on here who can do the job. Off the top of my head, call Randy at Watcon.

    Click the links below for lots more useful information.

    I just bought a Polaris PWC - what should I do?

    Polaris Fuji (blue) engine

  3. #3
    ditto on all of the above.

    Do Compression check first(which will determine what actually needs to be accomplished), then install Mikuni 3 output fuel pump, remove autoock valve, replace fuel filters, carb re-build (if you look closely at the square metal plate on the carbs you will probably see fuel leaking from the weep hole at the bottom), check oil lines, remove oil pump ,go pre mix. All of This more or less in that order.

    Then that leaves the drive system, center bearing lube(replacement) and open up the pump and replace the bearings/seals.

    But remember if you do all of that yourself you need a lot of mechanical experience and lots of tools, US and metric.

    It is hard to find someone to work on Polaris now. They claim no parts are available, but that's just not true.

    Cheers !!!

  4. #4
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Welcome to the Hulk.

    It really depends if water was ingested into the engine.

    How long was the ski flipped for?

    Was is righted in the correct direction? (there's a decal that shows the proper direction to prevent water from being dumped into the engine)

    Was the ski driven back to the docks, or was it towed back in?

    Was the water removed from the engine before trying to restart it? (spark plugs removed and start button pushed to expel most of the water)


    Conduct a few tests before you go buying parts.

    Compression test

    Crank phase/index (checking that pistons are exactly 120* apart)

    Check for water left inside the engine

    And check the electrical box for water intrusion.


    Start with these tests first, and let us know the outcome. We can help you better if we know the state of condition it's in.

    Please don't keep riding the ski in it's present state. Needing to pull the choke to achieve full RPM does mean there's a fuel delivery problem and can lead to piston damage.

    Then we'll work on the maintainence and upgrades.

  5. #5
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    Quote Originally Posted by GasTecH View Post
    I have a 95 sl 750 that I bought new. I hav no mods and never had any problems with it until the wife flipped it and since it feels that its not getting enough fuel. it has a hard time idling, and will only run at wot if the choke is slightly pulled. I am guessing that it is time to rebuild the carbs, or should i be looking at something else for the problem?

    Here is my question, since i have never rebuilt carbs, is there someone here that can handle this? Also, i would like some more performance, what are the first components that I should buy? Reeds? pipe? ride plate?

    thanks.
    Welcome back to the Hulk first of all!.You found the right place. The 95sl is a fun ski. I have a 94sl and a 95slt. They are fun arent they.

    Any polaris from the 90's is now 10-15 years old first of all. The time for fixing things and updating your ski is now.

    The fugi engines has a single outlet carb that works great for years until it gets weak, then a lean condition kicks in and it wont start,run smoothly,and can't go WOT throttle anymore.

    There are updates that polaris put out for all the skis at 1 point or another. I Had a recall on the gas cap on the slt. The (inside gas tank cap one), it seems to crack over time. this could include sucking air into the system and cause a lean condition.

    So looking at the updates for your ski is a must. some are easy, some may need a new part. So go look those up first.

    I see the wife flipped the ski huh!? opps! hate when that happens. Usaully, the first thing to do is get it out og the water and not run it. It could have water in the cylinders-hydro-locked. That could break everything inside if started like that. But you say it runs, so thats ok then.

    You still need to check if the crank is out of true. (mis-aligned). If its just a couple degress out it wont run right.

    If your pulling the choke out to get it running right, your giving it more fuel obviously and theres a reason for that. Must find out why before running it again!

    The sl's have a thing called an auto-cock as previously stated. That piece needs to be thrown out!.Its blue colored and plumbed into the fuel lines. I recommend that you get a fuel line routing diagram and buy a triple outlet fuel pump, all new fuel lines(25 ft/1/4 inch), and some plugs for the carbs.

    Theres diagrams on here to show you how to route the new lines.

    The triple outlet pump feeds all three carbs with plenty of fuel. so no worries about that part of the system. (35gl/hr). I think the ski at WOT uses 13gl/hr.

    Make sure all fuel lines are routed and not being kinked, or bent. Check and replace the lines in the gas tank too. 1 of them could have fallen off. They will be junk when u look at them. mine were wasted. Take the screens off the bottom of them(thery may have fallen off already and there sitting in the tank.(1 of mine was!). Keep track of how long each one is.
    The longer 1 is for the reserve tank fuel flow and the other is for the main fuel flow. if you switch them wrong, you wont have a reserve in your gas if you run out!. opps . so be careful when changing them out. Put the little screens back on them too. ok tank is done, check for debris in it too.

    The triple pump needs to be hung about 6 inches above the hull to keep "pulse fitting hose" which is a hose that connects to the bottom of the engine on the stbd side bottom of the ski from the fuel pump. if its on the bottom of the ski, it will suck leftover junk in the crabkcase and it wont run, the lkine has to be less the 12 inches. preferably 8 inches from the pulse lind outlet on the engine.Thats what gives you the air pulse to make the fuel pump work!. Repalce this line also.

    Check all clamps on every hose connection in the ski. 1 can cause problems! not too tight, not too loose. just right.

    Open up and take the fuel seperator apart and dump the water n gas out of it and clean the screen in there. Put it back together and check the big o-ring at the top of the jar as you put it back together.

    You can also check the fuel selector switch on the side of the ski to make sure all is good there. check the orings inside it for wear n tear ot missing.

    The carbs probably need cleaning just from age alone. Sometimes water gets into the diaphram and causes the pump to be weak in pumping gas.


    there are pretty easy to rebuild. No, you dont have to get all 300 pieces on the table! theres like 6 parts you need to replace. Theres guys on here that know exactly what to take out n replace.. I think exlint has the info!

    Some are... needle n seat, diaphram, fuel lines, low speed screw, high sopeed screw, adjustment idle screw.. Ask the guys and they will help you out on that.

    A compression gauge is vital in knowing the condition of the motor. Normal comp numbers would be 120,120,120 in the cylinders.. leave 2 plugs in,1 out, throttle open, full battery, and run the engine till the piston goes up n down at least 5 times at each test. do it again to be sure.Do it cold too. not hot. No oil in the cylinders either. that changes the numbers.you want a true reading.

    Write down all numbers you get and let us know,, 120 is great, 100 will run, but a little weak. 90 or below and you have trouble brewing.....

    Beerdart has a diagram of the fuel routing and carb install.

    There is a fuel restrictor in the return line to keep the fuel pressure up while running. it's located a half inch beyond the fuel rail on the return line going to the tank. It's the line that comes off the fuel rail towards the back of the ski on the carb rack. its the top hose, not the 1 underneath it. it will have a black zip-tie on it holding the restrictor in place. That has to be there!!!!! When you replace the lines, dont throw that out, it needs to be put back in there after the lines are replaced or else it wont run right.


    The pump in the back of the ski has 2 bearing in it that eventually get worn out and needs replacing.. You basically take the pump out, knock the bearing out and replace the seals and bearings and put it back together and your good to go. might want to check the impellor blades and check the condition of them . A bad impellor wont make the ski go very fast if broken or chipped.. Look at the blades inside the stator too. it has stationary blades that could be chipped or broken too. tell us what ya find there.

    Any mods your looking for are plenty. A ride plate will help in top speed or handling, or launch!.. an intake grate can help hooking up in rough water. theres sponsons, truing the hull,and a few others you could add to the ski.

    I would take care of biz first, and get her tuned right, then the mods later.

    The carbs take a little bit getting out. you will need a 12 mm wrench to get the bolts off. kinda a pita, but it does come out.. Tired of reading yet? Im tired of typing! lol Any questions, just ask. were here to help ya.!! Tom

    Maybe drain the tank too. get all the water n gas out of the tank if there was any in there.

  6. #6

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    wow. i have to say i am impressed at how fast i got replies. thanks.

    ok, it was flipped over for about 10 sec. i was on the back and turned it upright according to the arrows. i had to start it to drive it in.

    compression was 98-103. i replaced fuel filters and checked lines. the gas cap was replaced. However, i have been unsuccessful in getting to the filters and lines inside the tank. the unit will not clear the hull. i tried sliding the fuel tank forward, but still no clearance. how do i remove the sending unit?

    I have never rebuilt a carb, i feel i can, i am just not sure how to synchronize the tripple carbs.

  7. #7
    bowsniper's Avatar
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    [QUOTE=GasTecH;1332962]wow. i have to say i am impressed at how fast i got replies. thanks.

    ok, it was flipped over for about 10 sec. i was on the back and turned it upright according to the arrows. i had to start it to drive it in.

    compression was 98-103. i replaced fuel filters and checked lines. the gas cap was replaced. However, i have been unsuccessful in getting to the filters and lines inside the tank. the unit will not clear the hull. i tried sliding the fuel tank forward, but still no clearance. how do i remove the sending unit?

    I have never rebuilt a carb, i feel i can, i am just not sure how to synchronize the tripple carbs.



    Ok, it flipped for 10 seconds, not bad. turned over correctly. not bad again.. kewl....

    I would of taking the plugs out immediately and turned the motor over with the plugs out to get the water out if there was any. but ,,,,do that next time. could of blew the thing apart right then! lol

    Comp numbers are a little low.. Probably from normal use looks like. They look like there in the tolerence between cylinders too. 5% difference from each other. 10% would still run.. Maybe a re-ring at some point if the pistons and the bores are ok.. and of course the crank is good..

    You dont have to pull the whole thing out, just remove the hoses from the top of it. they will be hard to remove by the way!.. keep track of whats what. don't switch them around! Label them as you go.Then slide it up and see if the lines are on the cap or in the tank laying there. be careful with flames, your messing with gasoline now, could burn down the garage! or your house. better take it outside if ya can. that way your neighbors can watch it burn too! lol I'm kidding.lol

    Is the tank full of gas? Drain it if you can first. easier to see whats goin on in there. keep all the gas way away from your ski while working on it..like in another room or outside.!

    If you just replace the jets, needles and seats, gaskets in the kits, your carbs will be in the same position if you put the adjustment screws back in with the correct number of turns.

    Always count the amount of turns on any screw you take out and mark it down while replacing stuff. those setting are critical to a properly running ski.

    When you take down the numbers, we can check to see if they are in or out the correct number of turns, each one is specific.. such as,, 1/2 turn on 1 or a 3/4 turn on another.

    Theres info on here for those adjustments according to your year ski. look in the search function for it.

    Also might want to take off the heads and check the pistons out for scoring or black on the pistons or if there new looking.. black is lean, chocolate brown with dime sized clean spots id perfect and half clean or more is too rich.. tell us what ya see down the spark plugs holes first with a flashlight. then maybe take the heads off to check if they look bad.

    Theres also a couple bearing down by the driveshaft there with a fitting on it. thats a grease fitting and that needs to be greased all the time.. every couple rides. so do it every ride out to keep the bearing in good shape, just fill it till it bulges a tad and your good.

    it holds like 1 oz of grease/ using high temp bearing grease or a synthitic type for marine use is good too.

    Ahh crank indexing? hmm. I'm not the guy to ask on here... but you could bring the center piston to tdc and the other 2 should be the same height.. just a quick check, not super accurate.. If its out 2 degrees or more, you out of index. The crank has to be removed and an expert has to realign it. $$$$ opps..

    Theres a thread on that subject too.. just use the search function on the main page to look for it.


    The auto cock i think was for keeping fuel from getting to the carbs if iverted.. but anyways,, they deleted that eventually. its worthless. everyone gets rid of it and goes with the triple setup.

    The auto cock kinda looks like a little fuel pump kinda. it's near the fuel pump.. When you replace everything anyways, you start from scratch. so that will be part of what you'll be taking apart and throwing away.. It's in the threads on here..

    Hope this help ya out.. Everyone on here is very knowledgable about these skis and I'm just touching on some of the items that needs to be addressed for years of fun with no troubles. Take care if it, and it will take care of you.. Just ask..

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Quote Originally Posted by GasTecH View Post
    wow. i have to say i am impressed at how fast i got replies. thanks.

    ok, it was flipped over for about 10 sec. i was on the back and turned it upright according to the arrows. i had to start it to drive it in.

    compression was 98-103. i replaced fuel filters and checked lines. the gas cap was replaced. However, i have been unsuccessful in getting to the filters and lines inside the tank. the unit will not clear the hull. i tried sliding the fuel tank forward, but still no clearance. how do i remove the sending unit?

    I have never rebuilt a carb, i feel i can, i am just not sure how to synchronize the tripple carbs.

    I dont know how to do the crank phase/index, nor do i know what the auto-cock is.
    Good, sounds like minimal water intrusion if any.

    Did it start right back up, or take a while?

    Compression is a little on the low side. Normal would be around 120. Not that's your problem, but you're asking about performance gains, and getting the compression back up would definately add more performance.

    You really should replace the fuel hoses due to age. It'll only run you around $20 to do them. You can get about 20' of 1/4" fuel hose from an auto parts store. Just don't let them sell you the fuel injection hose that runs around $6 a ft.

    Inside the return hose (about 1 1/2" in) going from the carbs to the gas tank should be a small brass restrictor. Make sure to re-install that into the new hoses.

    Now would be a good time to replace the old fuel pump with a new triple outlet fuel pump. John Zigler sells them for about $26

    The auto cock needs to be removed if it hasn't already. Here's a pic of the auto cock to be removed and the restrictor that you need to re-isnatll.



    Also, another thing to look into is the fuel selector valve. The rubber inside will swell in time and restrict fuel flow. Not a bad idea to inspect it and the O ring seal while you're upgrading the old fuel system.

    The 95 750 should use the aluminum fuel pick up tube. If that's the one you have, there are no fuel lines inside the gas tank. But to remove it, you need to remove the bolts and slide the fuel tank forward. Then remove the scres holding the sender down and remove the sender. It's kinda a pain to do, but not that bad. It works easiest to pull the sender all the way up, and then lean it the direction of the "flat" side to get the bottom part out.

    The carbs are actually very easy to work on. Syncing them isn't much of an issue. If you don't touch the spring loaded screws that connect the carbs, you shouldn't even affect them. Even if you do, it's easy to adjust them any way.

    Here's a great kit for completely rebuilding your Mikuni Super BN 38mm carbs.

    http://cgi.ebay.com/ebaymotors/Polaris-PWC-Triple-Carb-Rebuild-Kit-OEM-Mikuni-Parts_W0QQitemZ250575431414QQcmdZViewItemQQptZPers onal_Watercraft_Parts?hash=item3a5775a6f6

    It has all genuine Mikuni parts, and also includes the needles and seats that are normally sold seperately.


    It may sound like alot of stuff, but it's really not that bad. If you look at it like this, the ski is 15 yrs old, and prob hasn't had anything done to it. So if you rebuild the fuel system now, it'll be good for many more years to come.



    Checking the crank phase the "redneck way" would be to use a dial indictaor to find "true" TDC on the CEN cylinder.

    Then squarely place a new pencil or dowel rod long enough into the spark plug of the MAG spark plug hole. Use a razor blade to make a mark on the pencil by holding it flat to the head.

    Now do the same for the PTO cylinder. The razor marks should be at identical same heights.


    The correct method would be to use a dial indiactor and a degree wheel. Zero "true" TDC of the MAG on the degree wheel, then find "true" TDC of the CEN and PTO cyls on the degree wheel. They should all be exactly 120* apart.

  9. #9
    bowsniper's Avatar
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    Does the 95 really have a alum deal inside the tank? My 95slt doesnt. nor does the 94sl. both have fuel lines with screens on them or did they just do that on the 95sl? thats weird,,,


    Cost of getting ski back up to snuff:

    Gas Cap-15.00
    Triple carb rebuid kit-130
    Triple outlet carb-30.00
    1/4 inch fuel line-20.00
    new clamps,tie wraps for oil lines.5.00
    Oil lines-3 feet-5.00(must replace--they crack lengthwise too. Not just sideways, Theyr'e brittle n old.)

    205.oo isn't too bad for everything. Are they NGK " BR8ES" Spark plugs in it? If not, thats whatcha need. Maybe cut the spark plug wires back a 1/4 inch and put the boots back on too.

  10. #10
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    Quote Originally Posted by bowsniper View Post
    Does the 95 really have a alum deal inside the tank? My 95slt doesnt. nor does the 94sl. both have fuel lines with screens on them or did they just do that on the 95sl? thats weird,,,
    Use this site to check any part for yourself.

    http://partsland.com/index.cgi?N=126...&P=Polaris-PWC


    The 95 SLT used both the old arm and float in early production, then switched to the aluminum tube like my newly acquired 95 SLT.

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