Stalling 750 SXI Pro (new purchase)
pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. #1
    PWCToday Newbie
    Join Date
    Jul 2019
    Location
    Tampa
    Posts
    14

    Stalling 750 SXI Pro (new purchase)

    Hey guys and gals. Just picked up a 98 750 SXI Pro that has been sitting for a while. Itís 100% stock except for a ride plate and intake grate. The owner wasnít super meticulous but didnít abuse it either.

    I dropped it in the lake as soon as I bought it and the JetSki would start and idle fine but die soon after getting up on a plane. Iíd have to choke it most of the time to restart. So to that end, I immediately rebuilt the carbs and replaced all fuel lines.

    Today, post carb rebuild, Iím having the exact same issues. It idles fine but canít run on a plane (or under load) for any amount of time. I also replaced the spark plugs and checked the compression which is a touch over 150 in both holes. Fuel is premixed with Klotz at 32:1 which I may lean out to 50:1.

    does anyone have any thoughts on why it wonít run under a load? Could it be the stator? The pipe also seemed to be a little hot and the pisser a little steamy which is odd since it wasnít really running hard. Thanks in advance for the help... Aside from draining the gas (in case there was some water in the tank) Iím at a loss right now.

  2. #2
    PWCToday.com Is My Home Away From Home john zigler's Avatar
    Join Date
    Mar 2003
    Location
    wisconsin
    Age
    52
    Posts
    8,817

    Re: Stalling 750 SXI Pro (new purchase)

    Is it still acting like a lean condition? (Your original description sounds as you were lean, using the choke to run better, etc)

    Could be an air leak. Look into info on doing a leak down test.

    When you rebuilt the carbs, did you use genuine Mikuni brand Kits? Did you replace needle and seats? What springs did you put back in for the needle arm? (IE Mikuni kits only come with 2 springs, and neither is correct for a stock SXi Pro. You need to re-use your originals)

    Were your carbs cleaned meticulously?

    Hot pipe, and steam from the pisser could be a blown head gasket. (Or cracked head, cyl, etc).
    RCJS also doing business as WATCON
    608-743-1305 9am to 5pm CST m-f
    email watcon@watcon.com

    Please visit our web sites

    new parts / products / services www.watcon.com
    used parts www.rockcountyjetski.webs.com
    thank you

    Please check out and like WATCON on Facebook

  3. #3
    PWCToday Newbie
    Join Date
    Jul 2019
    Location
    Tampa
    Posts
    14

    Re: Stalling 750 SXI Pro (new purchase)

    Thanks for the reply and insight. Yes, it’s definitely acting like it’s lean, still. I used a SBT rebuild kit because I’m local to them. I retained my original springs. Needles and seats weren’t replaced but I’m thinking that perhaps I should have.

    Head gaskets are cheap insurance so I’ll do that next week.

    Will report back after going through the carbs again and head gasket replacement.
    Last edited by Chadimac22; 07-17-2019 at 09:38 AM.

  4. #4
    PWCToday.com Is My Home Away From Home Myself's Avatar
    Join Date
    Jun 2006
    Location
    Arkansas
    Age
    42
    Posts
    5,595

    Re: Stalling 750 SXI Pro (new purchase)

    I would suspect the pickup assembly sucking air. It's an issue on many older Kawi's.
    http://www.facebook.com/twinlakesjetskirepair

    '89 Kawi 650SX 42.4 GPS
    +3" stock pipe, ported ex. manifold, drilled waterbox, blueprinted pump, Ocean Pro ride plate

    '99 Yama GP1200 65U 61.8 GPS
    ported cylinders, matched cases, milled head, blueprinted pump, long ride plate

    '96 Seadoo HX 717 53.13 GPS
    light porting, massaged cases, lightened flywheel, port matched manifolds, Rossier pipe, stubby pump cone

  5. #5
    PWCToday Newbie
    Join Date
    Jul 2019
    Location
    Pittsburgh, PA
    Posts
    26

    Re: Stalling 750 SXI Pro (new purchase)

    Quote Originally Posted by john zigler View Post
    Is it still acting like a lean condition? (Your original description sounds as you were lean, using the choke to run better, etc)

    Could be an air leak. Look into info on doing a leak down test.

    When you rebuilt the carbs, did you use genuine Mikuni brand Kits? Did you replace needle and seats? What springs did you put back in for the needle arm? (IE Mikuni kits only come with 2 springs, and neither is correct for a stock SXi Pro. You need to re-use your originals)

    Were your carbs cleaned meticulously?

    Hot pipe, and steam from the pisser could be a blown head gasket. (Or cracked head, cyl, etc).
    Out of curiosity, if the cooling system is working properly, the exhaust pipe wont be hot?

  6. #6
    PWCToday.com Is My Home Away From Home john zigler's Avatar
    Join Date
    Mar 2003
    Location
    wisconsin
    Age
    52
    Posts
    8,817

    Re: Stalling 750 SXI Pro (new purchase)

    Quote Originally Posted by topsecretchatz View Post
    Out of curiosity, if the cooling system is working properly, the exhaust pipe wont be hot?
    It will be warm, but not super hot (Sizzle water).
    RCJS also doing business as WATCON
    608-743-1305 9am to 5pm CST m-f
    email watcon@watcon.com

    Please visit our web sites

    new parts / products / services www.watcon.com
    used parts www.rockcountyjetski.webs.com
    thank you

    Please check out and like WATCON on Facebook

  7. #7
    PWCToday Newbie
    Join Date
    Jul 2019
    Location
    Tampa
    Posts
    14

    Re: Stalling 750 SXI Pro (new purchase)

    Update: pulled the carbs again, replaced both needles and seats and set pop off to 25 psi on the dot. While I was at it, I installed a primer kit. Still no dice.

    The jetski will start and idle with ease. However as soon as throttle is applied, it falls flat on its face and dies. Hit it with a couple primer shots and you can give it some throttle but as soon as those shots are burned, it will die if the throttle is open.

    The pickup lines are clear and the primer has no trouble pulling fuel. Plus, it idles really well.

    If there’s an air leak, will it be this drastic (ie: stall the engine)? Or does this sound fuel related still? I’ve completely gone through the carbs, cleaned thoroughly and rebuilt them with accurate pop off pressures. Could the fuel pump be bad? Or maybe a bad pulse from the engine? It just feels very fuel starved but I don’t know if it’s from an air leak or fuel related (bad carbs?).

    Any additional insight is greatly appreciated.

  8. #8
    PWCToday.com Is My Home Away From Home Myself's Avatar
    Join Date
    Jun 2006
    Location
    Arkansas
    Age
    42
    Posts
    5,595

    Re: Stalling 750 SXI Pro (new purchase)

    Pull the pickup. Use tubing to plug the ends. Submerse it in a bucket of water. Use another piece of tubing to blow air into the assembly. Watch for air bubbles coming out of the pickup.
    http://www.facebook.com/twinlakesjetskirepair

    '89 Kawi 650SX 42.4 GPS
    +3" stock pipe, ported ex. manifold, drilled waterbox, blueprinted pump, Ocean Pro ride plate

    '99 Yama GP1200 65U 61.8 GPS
    ported cylinders, matched cases, milled head, blueprinted pump, long ride plate

    '96 Seadoo HX 717 53.13 GPS
    light porting, massaged cases, lightened flywheel, port matched manifolds, Rossier pipe, stubby pump cone

  9. #9
    PWCToday.com Is My Home Away From Home wmazz's Avatar
    Join Date
    Jul 2013
    Location
    Riverside, CA
    Age
    59
    Posts
    2,673
    Blog Entries
    6

    Re: Stalling 750 SXI Pro (new purchase)

    Quote Originally Posted by Chadimac22 View Post
    It idles fine but can’t run on a plane (or under load) for any amount of time.

    Fuel is premixed with Klotz at 32:1 which I may lean out to 50:1.

    does anyone have any thoughts on why it won’t run under a load?
    Check for an exhaust or fuel leak.

    I recommend the 32:1 over 50:1

    If the engine starts easy an will idles without the engine quiting in ~30sec to 1 min,
    than a serious vacuum leak isn't likely. An exhaust leak will prevent the ski from getting
    on a plane, or a small amount of fuel inside the engine compartment.

    Has the engine ever been removed, or overheated?

    Once in a while, people will connect the exhaust hose to the water box, while
    there is a rag inside the waterbox or exhaust hose. A waterbox that is partially
    blocked inside will be low on power.


    Bill M.
    Horsepower == Speed, RPM != Speed



  10. #10
    PWCToday Newbie
    Join Date
    Jul 2019
    Location
    Tampa
    Posts
    14

    Re: Stalling 750 SXI Pro (new purchase)

    Thanks for all the input so far; I really appreciate the insight. I think I have *most of it solved.

    Today, I ran the ski on the trailer, in the water, with the hood off. During this, I noticed liquid dripping between the carbs. Upon closer inspection, it was the seal in the flush kit cap that had failed and spraying inside the engine compartment! This was also diverting water away from the water temp sensor, causing it to run hot, and killing my engine when I was trying to plane. It also explains why my pisser was steaming and the excessive water inside the hull.

    As luck would have it, I had a new flush kit on the shelf which I promptly installed. I’d say this solved about 75% of my issues. For the first time, I could get on a plane and stay there! I’m not reaching full rpm so I’m going to replace the top end gaskets, exhaust gaskets and hope for the best.

    It’s amazing how badly that leaky flush kit was making it run. Progress...

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0