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  1. #1

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    94 SLT 750 White emulsion in carb throats

    Hi all. Got about 2.5 hours on the new SBT rebuild now. It's running good, as good as it ever has for sure. While doing the tuning I noticed a small amount of white emulsified oil building up in the throat of the carb. This emulsion was in the carbs before I put in the new motor too. I completely serviced the carbs before firing it up with the new motor. I did the oil pump delete and the triple outlet pump upgrade too. I'm currently mixing fuel at 32:1 with the SBT break in oil. I will be mixing at 50:1 once I've burned through this first 8 gallons of fuel (which is very soon).

    The reeds have some chips on the corners, typical for a 25 year old ski. I tried to by new reeds for the new motor but 2 different ebay sellers stood me up on the orders because they were out of reeds for the 750. I cleaned and inspected the reeds. I flipped each pedal over so it had a little better contact and sealing. During tuning (spark arrester and upper/lower intake manifold removed) I could see a little blow back just as I hit the throttle. The reeds are definitely leaking but not enough to make the motor really stumble when I stab the throttle off idle.

    Could the chipped reeds and blowback be causing the white emulsified oil to build up in the throat of the carbs? That's really the only thing I can think of. What else could be causing this?

    Anyone have a suggestion where I can get a decent priced set of reed pedals for this thing. I prefer reeds in the $100-$120 range but will spend $150 if that is a better option.

    Thanks in advance for the help.

  2. #2
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    50:1 oil ratio is pretty low. Most of us run 40:1 Double check that the oil you're going to be using suggests 50:1. I'd hate to see you scorch the engine because you tried to save a few bucks on oil.

    The 650, 750, and 780 all use the same reeds. So if you can find a set for any of those, they will work.

    It's not advised to flip the reed petals (especially carbon fiber as they will most likely break)

    As for reeds, you have Boyesen and Carbon Tech available to you. Boyesen has fiberglass offerings for around $100 and carbon fiber for more. Carbon Tech I see are around $150. You can find them on Ebay, Amazon, or you can try John at Rock County Jet Ski or Watcon

    There is normally some blowback from the carbs. The white foam is usually water mixed with oil. It can be from water ingestion, or your carbs are sweating. If you don't see sweat on the carbs, see if the driveshaft is flinging any water that's inside the hull. If you don't have a safety cover over the engine coupler this can be a cause.

  3. #3

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    Quote Originally Posted by xlint89 View Post
    50:1 oil ratio is pretty low. Most of us run 40:1 Double check that the oil you're going to be using suggests 50:1. I'd hate to see you scorch the engine because you tried to save a few bucks on oil.

    The 650, 750, and 780 all use the same reeds. So if you can find a set for any of those, they will work.

    It's not advised to flip the reed petals (especially carbon fiber as they will most likely break)

    As for reeds, you have Boyesen and Carbon Tech available to you. Boyesen has fiberglass offerings for around $100 and carbon fiber for more. Carbon Tech I see are around $150. You can find them on Ebay, Amazon, or you can try John at Rock County Jet Ski or Watcon

    There is normally some blowback from the carbs. The white foam is usually water mixed with oil. It can be from water ingestion, or your carbs are sweating. If you don't see sweat on the carbs, see if the driveshaft is flinging any water that's inside the hull. If you don't have a safety cover over the engine coupler this can be a cause.
    Thanks for replying. All good suggestions. There is very little water in the hull but some. The coupling shroud is in place with the opening facing down. Not much water slinging from the drive shaft. The carbs were sweating some for sure. By mid day the white emulsion in the carbs was basically gone.

    I burned through the 8 gallons of break in oil today. I like your suggestion of 40:1. Oil is cheap and this motor is running too good to feed it less oil than needed. It barely smoked at 32:1 so 40:1 will be perfect. I'm all done with tuning for now. Plug color looks good and piston wash is just a little fat, a bit over 1/4" of wash o the pistons. It may get a little fatter once I put the intake manifold and spark arrestor back in place. From the stock settings, I added about 1/8th turn to the low and high speed screws across the board as a starting point and haven't changed those settings since first start up. I may have to screw that 1/8th turn back in if it's too rich with the intake plenum in place.

    I would like to buy new reeds from a forum sponsor or vendor who supports this forum. I've found plenty on ebay and such but would like to buy from forum supporters if possible. I'm new to this forum so I'm looking for suggestions on who here may be a good source for parts.

    Thanks again for the suggestions. I think you are pretty much right on.
    Last edited by AKIQPilot; 08-05-2020 at 02:24 AM.

  4. #4
    If you're struggling with finding reeds, I ran into the same issue. Wasn't keen on shelling out $120 on aftermarket, so I just found some used cages off eBay. Not saying it's the best idea, but was about 1/3 of the price of new reeds. (Holy hell are those things expensive!)


  5. #5
    sdlvx's Avatar
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    Using cheap oil isn't a good idea. Two stroke oil is responsible for keeping a lot of bearings in the crank and wrist pin lubricated. I'd rather run 50:1 Klotz KL101 or AMSOIL than 40:1 cheap Citgo oil.

    I run my pro 785s at 40:1 with Klotz because they are higher performance skis, basically superstock 750s. But I've ran my 650 superjet 50:1 with klotz for years, going out once or twice a week from early april to late october, and I've never had a single problem with it, though I probably jinxed it now lol.

    I'd run that 750 all day long with 50:1 QUALITY oil. I'd run it NEVER if all I had was cheap $15 a gallon oil. I had an SL 750 as my first ski. I never went to premix but the thing was nearly invincible, I've always been really impressed.

    I'd just spend the money on a case of Klotz or AMSOIL and have it shipped all at once. I like Klotz KL101 because it has benol in it, which leaves a dark film layer on a lot of things that helps protect from friction. But it makes it really hard to read piston wash because you just see benol.

    Fun fact, AMSOIL sells a 100:1 oil because it's high enough quality that you can cut down on the ratio by that much. I wouldn't ever run a ski at 100:1, but on some engines you can. The quality of oil matters, a lot. And I always cringe when I see people doing things like putting premium in their small engines and then using $20 a gallon citgo crap.

  6. #6

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    Quote Originally Posted by sdlvx View Post
    Using cheap oil isn't a good idea. Two stroke oil is responsible for keeping a lot of bearings in the crank and wrist pin lubricated. I'd rather run 50:1 Klotz KL101 or AMSOIL than 40:1 cheap Citgo oil.

    I run my pro 785s at 40:1 with Klotz because they are higher performance skis, basically superstock 750s. But I've ran my 650 superjet 50:1 with klotz for years, going out once or twice a week from early april to late october, and I've never had a single problem with it, though I probably jinxed it now lol.

    I'd run that 750 all day long with 50:1 QUALITY oil. I'd run it NEVER if all I had was cheap $15 a gallon oil. I had an SL 750 as my first ski. I never went to premix but the thing was nearly invincible, I've always been really impressed.

    I'd just spend the money on a case of Klotz or AMSOIL and have it shipped all at once. I like Klotz KL101 because it has benol in it, which leaves a dark film layer on a lot of things that helps protect from friction. But it makes it really hard to read piston wash because you just see benol.

    Fun fact, AMSOIL sells a 100:1 oil because it's high enough quality that you can cut down on the ratio by that much. I wouldn't ever run a ski at 100:1, but on some engines you can. The quality of oil matters, a lot. And I always cringe when I see people doing things like putting premium in their small engines and then using $20 a gallon citgo crap.
    Amsoil Dominator for me. I've been using it in all my 2 strokes since about 2002. I have dozens of snowmobiles, and they all use Dominator, some premix and some injected.

    I will blend at 40:1 for this buggy. Safe and trouble free. Burned another tank of fuel today. Ski is running good. Kids and grandkids had fun. Tubing and playing. So glad the little ones shamed me into pulling this old heap from the pile.

  7. #7

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    Quote Originally Posted by pascoea View Post
    If you're struggling with finding reeds, I ran into the same issue. Wasn't keen on shelling out $120 on aftermarket, so I just found some used cages off eBay. Not saying it's the best idea, but was about 1/3 of the price of new reeds. (Holy hell are those things expensive!)
    Yes, there are reeds available on ebay. I was hoping for a $100 set but it looks like only the $120-$150 reeds are available at this point. My reeds arent that bad. They are sealing very good with only minor chips on a few corners. I just want a fresh set to eliminate that as a potential issue. Have them in hand so the next time I pull the carbs I can throw in a fresh set of reeds.

  8. #8
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    They really are fun skis. Pretty light hull too. The newer models switched from fiberglass to SMC and gained about 70-80 lbs. Funny thing is they seem to have cracking issues while the fiberglass hulls (lighter ones) don't.

    Try John Zigler at Rock County Jet ski. He's not a sponsor, but he has helped many of us polaris guys for years. He also makes carb rebuild kits using just the Mikuni parts you need for our carbs. Good guy to deal with.

  9. #9
    BlueFishCrisis's Avatar
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    Quote Originally Posted by AKIQPilot View Post
    Yes, there are reeds available on ebay. I was hoping for a $100 set but it looks like only the $120-$150 reeds are available at this point. My reeds arent that bad. They are sealing very good with only minor chips on a few corners. I just want a fresh set to eliminate that as a potential issue. Have them in hand so the next time I pull the carbs I can throw in a fresh set of reeds.
    I can give you some reed options. PM me if you are interested.

  10. #10

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    Quote Originally Posted by BlueFishCrisis View Post
    I can give you some reed options. PM me if you are interested.
    Thanks for the offer.

    I did find a set of the $100 Boysen Reeds. I will put them in at the end of summer or the next time I need to pull the carbs.

    Pulling the carbs is pretty easy. I remove the bottom 6 reed flange bolts and that gives easy access to use a stubby 12mm ratchet wrench to get the carbs off. Its 15 minutes or less to get them off that way.

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