Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

joseph

1990 Suzuki LT 4wd need help running issue

Recommended Posts

my atv will start right up will idle fine soon as i try to throttle up engine dies,i have changed gas,new fuel pump and lines great compression 188 lbs.new coil new spark plug adjusted valves dont know what to do also rebuilt carb,any help wanted

Share this post


Link to post
Share on other sites


Possible air leak. Improper air filter/ dirty. Air fuel screw at wrong setting.
What's the year make and model

Sent from my SM-N920V using Tapatalk

Share this post


Link to post
Share on other sites


its a 1990 suzuki lt4wd ,i have tried every thing when it first started it ran like a 4cyl. would when only 1 cyl was fireing then it would clear up when i worked the throttle now it just only will run at a idle runs smooth at idle

Share this post


Link to post
Share on other sites

It really sounds like a fuel issue.  Have you checked the fuel tank for any blockage ? Maybe dirty filter if there’s one in place as well as a clogged fuel valve at the bottom of the tank.  Also could be dirty carburetor problems.   I would start from the ya k down to the carb and go from there.  

Share this post


Link to post
Share on other sites

Something was possibly missed. I’ve done it plenty of times. I’ve rebuilt my carb and put it all back together just to find something that was over looked.  It happens. Secondary looks do usually turn up the culprit  and if not then at the very least it completely rules out that portion of the problem. 

Share this post


Link to post
Share on other sites

thanks for advice but i have checked fuel flow even hooked up another tank so it would feed carb by gravity,also i bought a after market carb it does same thing iam not driving the atv its just sitting there in neutarl is there any thing electrical that could cause this? i sure appreceate the help i tried going to the suzuki forum site but after joining couldnt figure out how to ask a question cant even log in anymore its crazy how complicated that site is so i hope you guys can help me i have cleaned tank new fuel shut off new fuel lines new vacume line to fuel pump new coil new spark plug new plug wire new coil rebuilt carb set float

Share this post


Link to post
Share on other sites


E brake switch off? My kfx and my banshee have a rev limiter when it's on.

Sent from my SM-N920V using Tapatalk

Share this post


Link to post
Share on other sites

Your spark may be breaking down as the RPM’S come up.  This happened with my Polaris which had a rev limiter on it also.  

So @06kfx440 may have a point.

I was pointed in the direction of a faulty rev limiter on one of my bikes through the forum here. 

I purchased this spark tester and put it in line with the spark plug. Started and watched the spark break down/fail as I reved the bike.  I removed the rev limiter and my problem was solved.   Worth a shot and cheap enough to try. It’s also a good tool to have.  

Having ruled out the fuel system it may be time to start looking in the ignition system.  

Rev limiter

bad pick up coil 

stator coil problem

regulator

cdi box  

4 of the 5 above listed parts can be tested and the repair manual will explain as far as how and what numbers should be shown on the tester during this process. 

I attached  a pic of the spark tester. 

 

F5844F48-ACEF-4CD9-A89D-679349639777.jpeg

  • Like 3

Share this post


Link to post
Share on other sites
On 11/2/2018 at 3:33 PM, joseph said:

my atv will start right up will idle fine soon as i try to throttle up engine dies,i have changed gas,new fuel pump and lines great compression 188 lbs.new coil new spark plug adjusted valves dont know what to do also rebuilt carb,any help wanted

Is that the compression reading before or after adjusting valve  just wondering 

Share this post


Link to post
Share on other sites

just out of curiosity has the bike been sitting around for a while  ?

Share this post


Link to post
Share on other sites

not sitting around a lot compression 188 after valves checked they where actually ok also i had put after market air filter on it because putting carb on and off so much this atv is tough to work on with front and rear fenders on

Share this post


Link to post
Share on other sites


was just wandering because this would indicate bad gas or gummed up carb as most others have pointed out its either gas or electrical related

Share this post


Link to post
Share on other sites

Added ATV info to topic title and moved to Suzuki ATV forum. 😁

Share this post


Link to post
Share on other sites

Did you rejet because of the new air filter?

Sent from my SM-N920V using Tapatalk

Share this post


Link to post
Share on other sites

My bet would be coil related or fuel starvation.

  • Like 1

Share this post


Link to post
Share on other sites


Guest

Check the charging system. Sounds crazy I know but every now and then I get a machine that nobody can seem to fix. An over charge condition from the charging system will cause the CDI to shut down. At idle the machine may be showing 14-15 volts at the battery. As soon as you touch the gas the voltage shoots up (due to higher alternator rpm) and the Ignition system quits. The charging system should charge no more than 14.5v at 2500rpm or so. I usually do this as pre check before I actually start working on a machine. Sounds like you did everything else.

Share this post


Link to post
Share on other sites

I can tell you what the problem is Guaranteed!. So please attempt to try my option out . 

Every single Suzuki I have ever owned has done the exact same thing . Suzuki are cold hearted women . PERIOD. 

So what you do is start it with the choke on . Leave the choke on for a while. After about 5 or 10 minutes , the engine will start to Rev and Rev and Rev until it's almost redlining. Then and only then take or turn your choke off . If it's a lever that you pull up , you may have to lightly tap it down a hair at a time . Like tap , revs lower but stays running , tap again , lowers Rev  etc. Until it's off and it stays running and idles with no choke or throttle . Then you can take off , shifting and giving it throttle . If the doing the steps does not allow it to idle on its own , adjust your idle screw so it does. Suzuki carbs are ULTRA ULTRA sensitive with this adjustment , so it may not run with a quarter turn left or right , but it will at an Eighth of a turn . So don't give up , it just takes a while , but once you get that idle screw perfect, Don't ever touch it again EVER. Then you only have to deal with the choke. This is the way all Suzukis are engineered to work . Trust me . Although every post on here has good intentions , I guarantee you success . Good luck my brother.

Share this post


Link to post
Share on other sites

thanks i will try that the thing is it never did that before since i bought it i rebuilt the carb at least 5 or 6 times finally bought a different new carb from a place that could get a aftermarket one it ran great for a year and a half  then it would start this i would work the throttle it would straghten out but now it wont . the one thing i noticed was that neddle with the groves is a 1[8 in longer then in a kit ive even tried different kits all have the shorter needle  iam 79 was a heavy equipment mechanic many years figured i could fix about anything but not this ILL TRY WHAT YOU SAID AND THANKS

  • Like 1

Share this post


Link to post
Share on other sites

Had same issue with my 1994 yamaha big bear 300. Ended up being the vent hose being plugged on carb. Used compressor to blow out lines and runs like a top. I did the whole carb rebuild and clean, spark plug and other things and ended up being a very simple fix. Good luck

Share this post


Link to post
Share on other sites
8 hours ago, Kent Mettler said:

Check the charging system. Sounds crazy I know but every now and then I get a machine that nobody can seem to fix. An over charge condition from the charging system will cause the CDI to shut down. At idle the machine may be showing 14-15 volts at the battery. As soon as you touch the gas the voltage shoots up (due to higher alternator rpm) and the Ignition system quits. The charging system should charge no more than 14.5v at 2500rpm or so. I usually do this as pre check before I actually start working on a machine. Sounds like you did everything else.

this is actually very useful thanks for the information! 

Share this post


Link to post
Share on other sites


Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Topics

    • By JacobSlabach
      i know this isnt an atv but same type of thing.  I have a riding mower im fixing and selling for my aunt and it has a dead battery.  i jumped it off my atv and when i turn the key nothing at all happens.  i tried jumping the relay still nothing.  this is with the seat down.  you wouldnt think this mower would have issues as its a top-of-the-line brand and almost brand new (aunt found it for a good price, still got tits on tires, just sat for a couple months in a mechanic shop
    • By Bud03420
      I just got this bike and not getting any spark I know nothing about it so before I spend any money on it I like to see if it fires dose it have to have a battery to complete a circut and spark cause it dosent have one
    • By AimlessMoto
      Hey guys, new here, but haven't found ANY answer to my specific problem on a Suzuki dedicated ATV forum, so here's to hoping!
      I acquired a 95' Quadrunner 250, 4x4, (LT4WD) for practically nothing with no spark. The PO had tossed in a used stator which didn't fix the problem... so I went all routes (though cheaply) to narrow down the initial problem of no spark. 
      Plug, coil, CDI (caltric) and stator w/pickup (caltric) were purchased and installed. And it RAN, but bogged horribly and would not rev past 1/4 throttle. 
      I checked fuel flow, vacuum lines, all the normal stuff, no issues. I decided to check the valves and cam... well, there was one problem. The cam was 1mm under the lowest spec in the manual. So, in-came a new cam, Stage 1 Hotcams... also threw in a new set of shindy valves, lapped them, replaced the valve seals, and the timing chain. 
      Back together again (w/stock airbox and new oiled filter). Now it idles even better, still boggs at 1/4 throttle, but will rev past it if you hold the throttle open for a second. Ahaha... success!
      So I was able to ride it above 1/4 throttle once I had momentum... could shift through the gears, all was good as long as I kept it over 1/2 throttle. Took a long enough ride to break in the cam properly at least so I won't have to worry about that. 
      Now, I start fiddling with the carb. It's clean as a whistle, stock, with stock jets (new replacement Mikuni jets). Same problem. 
       
      I start thinking, maybe this is fuel related and the bike is having an issue transitioning from idle jet to main jet... so I LOWER the needle by raising the clip 1 spot. Now it revvs up in neutral with no bog, but it boggs about the same trying to ride it. So I move the needle down again with the clip on the top slot. Better, but still has a bit of bog at 1/4 throttle. 
      The last bit of advice I got was to ditch the CV carb... so I sprung for a brand new Mikuni VM30-83 round-slide. Bolted it up, blew into the vacuum tube to fill it with fuel (no vacuum port on this one) and she fired right up... but there is still a bit of bog, it's just masked by the fact that I'm not waiting for the vacuum diaphragm to open. 
       
      So I feel like each little step brings me closer, but not perfect. I'm now wondering if this is still in-fact a carb tuning issue (I have some jets I can fiddle with and maybe lean-out the idle jet a little.) OR if the cheap-a** Caltric Stator/Pickup is what's causing these issues. 
       
      I have a 95' KingQuad with 400 miles on it... like new.. runs like a top... I've tried both the stock QR and the Caltric CDI boxes on it, and it revvs up and runs like a champ. 
       
      The only unknowns between the two systems are the carb, and the stator/pickup. My next step in troubleshooting is to rip apart the King Quad and test it's CDI on the Quadrunner... but considering there is no change to how it runs I doubt it will lead to a solution. 
       
      HOWEVER... I tried the stock CDI just recently after running the Caltric this whole time, and the bike runs like garbage. Hardly idles, and won't rev up at all. So, that is my one smoking gun telling me that it's either the pickup coil or the stator itself. 
       
      Has anyone had a problem even CLOSE to this? I can't image the carb would be causing this many issues, especially going to 2 different ones, both with stock jetting to OEM, and exhibiting the identical symptoms... the only change is when different CDI's are plugged in, or when the needle valve leans out the mixture. 
      Also, I checked the piston, rings and bore when I had it apart and they're like-new... no scoring, rings are loose, cylinder is still round and has honing marks still int he bore. Stock piston, stock bore size and it has 160psi compression. Battery is brand new, and I've tried 3 different R/R's, none of which change any symptoms, but slightly vary the charging voltage by .2-.5 of a volt depending on which unit. Also tried a new coil which changed nothing. 
      ANY help would be appreciated. Too much invested to not get it running right. 
    • By Gary Patch
      Hi my linhai 300 is hard to start and  engages gears at idle which is 1200 rpm was looking at cdi says on it 7500 rpm does this mean quad should idle at 7500 rpm as this would explain transmission problemb as idle is too high thanks gary
    • By David Barsukoff
      Hey, I just bought the kids a LT80 and noticed a small puddle under the machine after they were riding it for a bit. I'm wondering if anyone knows why the fluid coming from the fuel shut off is a red colour, and would have any ideas of where this issue is coming from? I haven't had a real good look at it yet, thought I would ask first. 

  • Similar Tagged Content

  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...