Home Forums General Karting Discussion Motor won't start, need help…

This topic contains 45 replies, has 5 voices, and was last updated by  David hofflinger 3 years, 3 months ago.

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  • #47910

    David hofflinger
    Participant

    Hi I’m new to the karting world and I got a 2007 Iame motor and a new digital key ignition system kit with the harness from Comet Kart. Now I had to rebuild the motor due to bad bearings. Also, before that everything started just fine. No issues with the ignition of anything. But now that I’ve put everything back I go to turn the motor over and it does turn over and it does suck in gas but it only sucks up gas for a short time then it comes back out of the carb. I have no idea what’s going on here because everything’s out together the same way it was before. And the spark plug looks like it’s not getting a big enough spark like it did before. It actually doesn’t spark but it still shocks you if you touch it. Any help would be great.

  • #47912

    tony zambos
    Participant

    David,
    If you’ve had the carb off, you may have reinstalled the gasket between the engine and carb incorrectly. There is a small hole in the engine block beneath the gasket and there is a corresponding hole in the gasket. Make sure the holes line up. You will also see the same hole in the carb. That passage port, or hole, is the pulse line for the fuel pump in the carb.
    Also, check the ground wires.

    LAD Specialties customer / tony kart / rotax / kt100

  • #47919

    David hofflinger
    Participant

    Thank! I’ll check that out. I actually took apart the car yesterday to check and it didn’t look blocked but I never noticed the hole for the gas going in. Hopefully that’s the problem. If not then I’m still lost.

  • #47920

    David hofflinger
    Participant

    <p>So that did not work </p>

  • #47922

    David hofflinger
    Participant

    <p>Fuel is being sucked up only through the carb and back out of the front of it. Not even making it into the motor and I checked all the holes and everything and it’s all lined up. Did I put the motor together wrong? Maybe I didn’t torque the bolts to spec? </p>

  • #47925

    tony zambos
    Participant

    David,
    Lets start with a little background. When you got the motor, did it have a key start or was that something you added? Did you do the engine work or was it done by a kart shop? I’ll assume that you have the Leopard Overhaul manual plus the Assembly Instructions and User Manual.

    Check the needle valves in the carb are properly set and that the butterfly is completely closed.

    If you serviced the card, here is a link to a video to compare with what you have done. https://www.youtube.com/watch?v=QpkK2v3jI74.

    It’s not uncommon to have an ignition failure on a Leopard. As a new comer, it might be wise to have a kart shop diagnose and repair your engine. Could also be cheaper going that route and will be less frustrating.

    LAD Specialties customer / tony kart / rotax / kt100

  • #47926

    David hofflinger
    Participant

    <p>I checked my carb again and it’s all together right it looks. It’s still not sucking gas into the motor. I’m honestly stumped. My last resort would be to take it to my local track and get one of there mechanics to mess with it.</p>

  • #47928

    David hofflinger
    Participant

    When I push the throttle should anything move in the carb up or down? Because nothing happens. I’m just taking guesses now.

  • #47931

    tony zambos
    Participant

    I’m still assuming that you have a Leopard engine. If so, nothing is going to up and down in the carb. A slide type carb, which you should not have on this motor does have a plate the moves up with depressing the gas pedal. Your carb has a round plate in it that rotates on a shaft when the gas pedal is pressed. The resting position of the throttle plate closes the large opening thru the center of the carb. When pressing your gas pedal, you see the linkage on the outside of the carb move.
    For now, your best bet is to let some one help you that can see and touch the motor.

    LAD Specialties customer / tony kart / rotax / kt100

  • #47932

    David hofflinger
    Participant

    <p>I was just asking if that’s how this carb works, again I’m new to this. But if I had a kart mechanic anywhere around here is definitely go to them. But until then I’d like to try to figure this out. All I know is fuel is not getting into the motor and no combustion, but there is a spark. If you guys are as stumped as I am I don’t blame you. </p>

  • #47936

    tony zambos
    Participant

    Remove the air filter and fuel line from the carb. Place the palm of one hand over the inlet to the carb and with the other hand hit the starter for 3 or 4 seconds. You should feel some suction.

    If the plug is at all wet, replace it or remove it until it’s dry.

    Is the throttle plate moving when the gas pedal is depressed?

    LAD Specialties customer / tony kart / rotax / kt100

  • #47949

    David hofflinger
    Participant

    I’ll Che k that tomorrow. Also, what does it mean when I look for a new piston and it says Red Dot or Blue Dot?

  • #47980

    tony zambos
    Participant

    General piston info: http://ekartingnews.com/forums/topic/pailla-leopard-questions/

    LAD Specialties customer / tony kart / rotax / kt100

  • #47984

    Walt Gifford
    Participant

    Did you put new crankshaft seals in it and seal the split line? Did you take the carb apart again and check the gaskets. The pulse has to get up to the pump. Did you mess with the reeds? Is the fuel line wired on to the carb so it doesn’t have an air leak?

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #48004

    David hofflinger
    Participant

    I’m thinking its to low of compression from the old piston and ring. Maybe when I put it back together it’s too low now and it won’t suck up the gas through the carb

  • #48006

    Walt Gifford
    Participant

    Well pour a little gas in the spark plug hole and see if it fires up for a few seconds. That’ll tell you if the basic engine is working.

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #48013

    David hofflinger
    Participant

    I did that, no combustion. But the piston and everything is working how it should. It went together exactly how it came apart.

  • #48410

    David hofflinger
    Participant

    <p>My bore measured 53.47. I can only find Pistons starting at 54 on Comet Kart sales.</p>

  • #48431

    Walt Gifford
    Participant

    You said it was running before you worked on it so it should run. Did you re-check the ground and all the wires and try a new plug?

    Gif

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #48435

    David hofflinger
    Participant

    Yep, everything went together and plunged in the same way it way before. Just after the rebuild no fuel is being sucked up into the motor, just the carb. And the carb is fine so I still can’t figure it out. I guess once the new piston comes in I’ll see if it actually was a compression issue. I also tongues everything to specs so that may have been another issue before

     

     

     

     

  • #48438

    Jim Derrig
    Participant

    Your compression should easily exceed 200 psi.  The bore cannot possibly be 53.47, as the bore new is 54.00, so your tools or technique are off.

    This is real basic, but are you choking the motor for a cold start?  First start can be a bitch for a rebuilt Leopard.  To choke it, put the air box on and place your hand over the inlet tubes.  You might have to slightly wedge open the throttle with a piece of thin (3mm) plastic or get somebody to manipulate the throttle.  You actually can leave the key in cranking position and have one hand doing the choking and the other working the throttle.  I’ve also resorted to spraying starting fluid in the inlet.

    You haven’t clarified whether you were using the key start ignition before the rebuild, or if that also is new.  The crank trigger magnet for a push-button Leopard is different than for a key start, so if you mixed them up you can get a very weak spark but no start.

    At low speed cranking (like with a starter) the carb can dump too much gas into the air intake plenum, so you’ll get leakage of the excess gas out of the plenum,  that you might interpret as gas not getting into the motor.

  • #48439

    Finch Guenther
    Participant

    I know very little about tag engines but, from what you said about the bore size you either measured wrong or you don’t have a leopard. If the measurement was correct then I think you have a Iame jaguar. I know the two engines are very similar but I don’t know exactly what parts cross over.

    Finch Guenther

    #51 CRG KPV

  • #48440

    David hofflinger
    Participant

    Sorry I thought I deleted that comment, it’s a Leopard I just measured wrong sorry

  • #48443

    David hofflinger
    Participant

    I actually got the key ignition kit from comet kart sales. Came with everything

  • #48445

    David hofflinger
    Participant

    I never thought of choking the motor like that, I’ll let you know once I try it. Thank you all for the help

  • #48446

    David hofflinger
    Participant

    What is the crank trigger magnet? I got a magnet that goes in between the stater, but it doesn’t fit properly on my crank shaft, the original magnet fit but the new one the kit came with is bored way too big

  • #48478

    Jim Derrig
    Participant

    The trigger/magnet fits over the crank, on the  side of the motor nearest the seat, and sits inside the “donut” of the stator. The magnet position is fixed by a key in the keyway on the crank output shaft.

    If the “original magnet” you speak of was off a push-button start ignition system, it won’t work correctly with the key start system and this explains your weak spark.  Though, to be honest the motor will run with the wrong magnet (I’ve done it–blush) so this does not totally explain the non-start.  My guess is the the weak spark combined with no choke may be the reason.

    Seriously, get some starter fluid for the first start.  Not ideal, but at least it’ll catch, you’ll get the break in started, and the next start should be easier.

    I have no explanation for why the new magnet would be “bored way too big,” as the magnet bores are identical for both (the crankshaft diameter for all Leopards is the same).  Wait, maybe it’s the trigger for the X-30 engine and they sent (or you unknowingly ordered) the wrong ignition kit?

     

  • #48504

    David hofflinger
    Participant

    <span style=”color: #000000; font-family: UICTFontTextStyleBody; font-size: 17px; line-height: normal;”>When I tried starting it before I used starting fluid but nothing happened. I did not choke it though, the only thing is when I bought the motors used before I rebuilt it, all I had to do was spray the starting fluid in the carb and it started right up. I’ll try to choke it like you said. I’m hoping that’s the issue. </span>

  • #48514

    David hofflinger
    Participant

    Like, even when the motor turns overs the gas doesn’t get sucked into the motor, just sold out the carb. And it won’t even attempt to combust, it just turns over. Can choking it be the cure? Also before I rebuilt the motor starting fluid started it right up, I tried spraying starting fuild into the carb recently after I rebuilt it and I got nothing. But tomorrow I’ll attempt to choke it like you said and hopefully that’s the problem.

  • #48543

    Jim Derrig
    Participant

    If fuel is going through the carb into the plenum, then there has to be some compression pumping the fuel.  The only way I can imagine that NO fuel would  go from the plenum into the crankcase is if the reeds were completely shut somehow.  As I said earlier, the volume of fuel going through the carb is so great at low rpm that you’ll get quit a bit of it dripping out the front of the carb.  Seriously, on my X125t I get fuel dripping out the front even at 4000 rpm.

    If you use starter fluid it should fire without choking.

    I’m pretty much at a loss and suspect there is something misassembled on the motor, or your ignition system is for an X30 and the timing is so far off the motor won’t start.  You might have to bite the bullet and take it to a kart shop where somebody can give it a hands-on look, as remote internet diagnosis isn’t working.

     

  • #48546

    David hofflinger
    Participant

    If only there was a kart mechanic around Vineland New Jersey lol

  • #48547

    David hofflinger
    Participant

    Now I put the motor and everything back together again, new issue, the kart won’t turn over now. At all. It looks stuck

  • #48559

    Jim Derrig
    Participant

    Well, this pretty much confirms my guess that something was misassembled the first time.

    You’ll have to put the motor in a box and send it to a builder.  I know–$$–but at this point you don’t have much choice.  I’m way over on the left coast, so I can’t recommend anyone over there.  Italian Motors was the IAME importer for decades and knows more about the Leopard than anyone else.

    http://www.italianmotorsusa.com/pages/im-engine-building-department

    Or you could just trade it in for an X125t–be the first on your block to own one :)  Might be cheaper in the long run.

    X125T Engine Package <p style="color:red">*TRADE IN PROGRAM*</p>

  • #48589

    David hofflinger
    Participant

    I found out it’s the new cylinder. It’s a hair to short for some reason and making the piston hit the head. I’ll need s thicker gasket and then it should run. S

  • #48597

    Walt Gifford
    Participant

    Dave, you know I’m in Bridgeton.

    Gif

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #48625

    Jim Derrig
    Participant

    I’m not a pro engine builder but I’ve rebuilt and successfully raced about 6 Leopards and I don’t think the sort of interference you’re talking about is possible with correct parts and assembly.  I’ve never measured it, but there is ample clearance from the top of the piston to the top of the cylinder, and the concave shape of the head should make contact impossible.  Something is seriously out of spec and I’d be concerned about interference popping up again after the parts heat up and expand, as the available gaskets are not that different in thickness.  You should never have to fashion your own gasket to create clearance on this motor.

    I know you want to save $ but seizing the motor at 15,000 rpm will not be the way to do it.  I’m a DIY guy all the way, but as Dirty Hairy said “A man’s got to know his limitations.”  Sometimes you just gotta bite the bullet and pay the man.  Heck, for all you know you’ll get it so the thing will rotate again and you’ll only be back to it not starting.

  • #48640

    David hofflinger
    Participant

    <p>I just send back the cylinder I got on eBay, the one that was too short, the guy actually shimmed the top of it off and didn’t tell me. So I dropped the old one back on just to see and it turns over fine now. Weird. And Walt, you’re in Bridgeton? If I need help I’ll contact you somehow</p>

  • #48687

    David hofflinger
    Participant

    So I’m getting spark and I tried choking the motor, I’m getting nothing still. I even tried starter fluid right in the cylinder and nothing. I’m at a loss for words. Carb seems to be sucking in gas. Everything is lined up.

  • #48693

    Walt Gifford
    Participant

    Compression, fuel or spark has to one of those 3. Are you flooding it?

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #48714

    David hofflinger
    Participant

    GOOD NEWS! I got it running. I still don’t know how but I tried the old spark plug and it started right up. For some reason the new plugs were not working and I know…it’s strange.

  • #48734

    Jim Derrig
    Participant

    It’s possible your the lead wire off the coil is broken or beat up to the point it doesn’t work consistently any more.  Usually its then end with the spark plug boot.  Try twisting off the boot, cutting off an inch of wire or so and twisting the boot back on.

    The coils themselves are almost indestructible.

  • #49479

    David hofflinger
    Participant

    Okay, so I had the kart running and stupid me forgot to put the small o rings on for the cylinder head bolts…Coolant leaked out while running and went into the cylinder and stopped the motor. Now I dried everything out and now the motor will only turn over…it won’t coma bust so I’m back to squar one. And today after I’d crank it the starter stopped engaging…I assumed it was a bad battery and bad starter so I got a new starter and battery…still doesn’t work. The motor turns over but the starter won’t engage to grabs the clutch. In all honesty I’ve never worked on anything so temperamental and confusing.

  • #49740

    Walt Gifford
    Participant

    Maybe try fishing?

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #49785

    David hofflinger
    Participant

    Alright I fixed it, come to find out it was the starter and bad battery. The only question I have now is why it won’t keep running if I let off the gas, I have the idle screw set up but the motor dies as soon as I let off. It’s a 2 stroke and I know a lot of guys who race dirt bikes don’t want there bikes to idle at all.

  • #49787

    Walt Gifford
    Participant

    If you want it to idle screw in the low needle until it idles but when you get on the track it will be lean under load. If you want to run it on the stand with the track setting you have to keep revving it but running on the stand will foul your plug so only run it for a few seconds to prime it for the grid.

    Gif

    FAA certified jet engine and aircraft technician,
    Nicholson Speedway class champion 2001,
    Yamaha KT100 Service Center,
    41 years karting experience

  • #49792

    David hofflinger
    Participant

    Perfect, thank you everyone for the help. It means a lot. I can finally says it’s ready to race.

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