Stubborn LT80
Mar 12, 2010 | 08:32 AM
#1
Thread Starter
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Trailblazer
Joined: May 2006
Posts: 45
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Stubborn LT80
I have a 2002 LT80. It is mostly stock. Head has been milled to slightly increase compression, oil injection blocked off, 2 clutch rollers removed, Banshee fuel petcock. Top end is about two years old with moderate use.
Problem: It runs great when you are out riding it. When you stop and let it idle, it will eventually die. After it dies, it refuses to start. The only method that seems to work is pumping the throttle while you run the starter. Most of the time, you REALLY have to pump the throttle before it starts.
Attempts to fix: Cleaned carb (several times), verified float level, checked for fuel from tank to carb (good), checked reeds (new Boyesen dual stage), checked compression (excellent), ran engine and sprayed starting fluid around gasket areas (no leaks detected), main seals look good, top end gaskets look good, spark plug looks great (I replaced it anyway), looked at piston/rings through exhaust & intake ports (all looks good), verified electrical components meet service manual criteria.
FYI...last year I wrestled with a problem where the same LT80 would die when you would attempt to climb long, relatively steep hills. I ended up rebuilding the carb (several times) and that seemed to remedy the problem...maybe these two problems are connected (daughter has not been up any hills of that nature for a while).
I am not sure what to check next. I still believe that this is a carb problem, but I have cleaned and checked it several times (this is not my first time at the rodeo). Maybe I should try another carb? Any suggestions would be appreciated.
Problem: It runs great when you are out riding it. When you stop and let it idle, it will eventually die. After it dies, it refuses to start. The only method that seems to work is pumping the throttle while you run the starter. Most of the time, you REALLY have to pump the throttle before it starts.
Attempts to fix: Cleaned carb (several times), verified float level, checked for fuel from tank to carb (good), checked reeds (new Boyesen dual stage), checked compression (excellent), ran engine and sprayed starting fluid around gasket areas (no leaks detected), main seals look good, top end gaskets look good, spark plug looks great (I replaced it anyway), looked at piston/rings through exhaust & intake ports (all looks good), verified electrical components meet service manual criteria.
FYI...last year I wrestled with a problem where the same LT80 would die when you would attempt to climb long, relatively steep hills. I ended up rebuilding the carb (several times) and that seemed to remedy the problem...maybe these two problems are connected (daughter has not been up any hills of that nature for a while).
I am not sure what to check next. I still believe that this is a carb problem, but I have cleaned and checked it several times (this is not my first time at the rodeo). Maybe I should try another carb? Any suggestions would be appreciated.
Mar 12, 2010 | 11:51 AM
#2
Trailblazer
Joined: Aug 2009
Posts: 84
Likes: 0
From: Milan, MI
After riding it for a while and then shutting it off do you also turn off the fuel? The problem you describe sounds like when a lt80 is flooded with fuel from those crapping fuel stops that don't really stop the fuel. I have one that does that and the engine get flooded with fuel and you have to crank it with the throttle at full for like a full minute before it will slowly start to sputter to life again.
Mar 12, 2010 | 02:46 PM
#3
Range Rover
Joined: Oct 2008
Posts: 110
Likes: 0
I have a 2002 LT80. It is mostly stock. Head has been milled to slightly increase compression, oil injection blocked off, 2 clutch rollers removed, Banshee fuel petcock. Top end is about two years old with moderate use.
Problem: It runs great when you are out riding it. When you stop and let it idle, it will eventually die. After it dies, it refuses to start. The only method that seems to work is pumping the throttle while you run the starter. Most of the time, you REALLY have to pump the throttle before it starts.
Attempts to fix: Cleaned carb (several times), verified float level, checked for fuel from tank to carb (good), checked reeds (new Boyesen dual stage), checked compression (excellent), ran engine and sprayed starting fluid around gasket areas (no leaks detected), main seals look good, top end gaskets look good, spark plug looks great (I replaced it anyway), looked at piston/rings through exhaust & intake ports (all looks good), verified electrical components meet service manual criteria.
have you soaked the jets & carb over night & boiled them yet?
FYI...last year I wrestled with a problem where the same LT80 would die when you would attempt to climb long, relatively steep hills. I ended up rebuilding the carb (several times) and that seemed to remedy the problem...maybe these two problems are connected (daughter has not been up any hills of that nature for a while).
I am not sure what to check next. I still believe that this is a carb problem, but I have cleaned and checked it several times (this is not my first time at the rodeo). Maybe I should try another carb? Any suggestions would be appreciated.
Problem: It runs great when you are out riding it. When you stop and let it idle, it will eventually die. After it dies, it refuses to start. The only method that seems to work is pumping the throttle while you run the starter. Most of the time, you REALLY have to pump the throttle before it starts.
Attempts to fix: Cleaned carb (several times), verified float level, checked for fuel from tank to carb (good), checked reeds (new Boyesen dual stage), checked compression (excellent), ran engine and sprayed starting fluid around gasket areas (no leaks detected), main seals look good, top end gaskets look good, spark plug looks great (I replaced it anyway), looked at piston/rings through exhaust & intake ports (all looks good), verified electrical components meet service manual criteria.
have you soaked the jets & carb over night & boiled them yet?
FYI...last year I wrestled with a problem where the same LT80 would die when you would attempt to climb long, relatively steep hills. I ended up rebuilding the carb (several times) and that seemed to remedy the problem...maybe these two problems are connected (daughter has not been up any hills of that nature for a while).
I am not sure what to check next. I still believe that this is a carb problem, but I have cleaned and checked it several times (this is not my first time at the rodeo). Maybe I should try another carb? Any suggestions would be appreciated.
Mar 21, 2010 | 09:44 PM
#6
Thread Starter
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Trailblazer
Joined: May 2006
Posts: 45
Likes: 0
more info
#1 The jets are clear.
#2 I put a Banshee petcock on it last year (and blocked off the vacuum line on the carb). I do not turn it to the "off" position between runs.
I don't believe that the fuel flowing all the time as being the problem. Again, the quad runs great when you are racing around. It is when you let it idle for a while. At some point it will die and then you have to pump the throttle (a bunch) to get it to start.
I am leaning towards trying another carb.
LT80 - do you have a used carb? Send me a PM or email if you do.
Has anyone tried the aftermarket LT80/KFX80 that is being sold on Ebay? It is supposed to be a direct replacement for the OEM.
#2 I put a Banshee petcock on it last year (and blocked off the vacuum line on the carb). I do not turn it to the "off" position between runs.
I don't believe that the fuel flowing all the time as being the problem. Again, the quad runs great when you are racing around. It is when you let it idle for a while. At some point it will die and then you have to pump the throttle (a bunch) to get it to start.
I am leaning towards trying another carb.
LT80 - do you have a used carb? Send me a PM or email if you do.
Has anyone tried the aftermarket LT80/KFX80 that is being sold on Ebay? It is supposed to be a direct replacement for the OEM.
Mar 22, 2010 | 03:58 AM
#7
Range Rover
Joined: Oct 2008
Posts: 110
Likes: 0
#1 The jets are clear.
#2 I put a Banshee petcock on it last year (and blocked off the vacuum line on the carb). I do not turn it to the "off" position between runs.
I don't believe that the fuel flowing all the time as being the problem. Again, the quad runs great when you are racing around. It is when you let it idle for a while. At some point it will die and then you have to pump the throttle (a bunch) to get it to start.
I am leaning towards trying another carb.
LT80 - do you have a used carb? Send me a PM or email if you do.
Has anyone tried the aftermarket LT80/KFX80 that is being sold on Ebay? It is supposed to be a direct replacement for the OEM.
#2 I put a Banshee petcock on it last year (and blocked off the vacuum line on the carb). I do not turn it to the "off" position between runs.
I don't believe that the fuel flowing all the time as being the problem. Again, the quad runs great when you are racing around. It is when you let it idle for a while. At some point it will die and then you have to pump the throttle (a bunch) to get it to start.
I am leaning towards trying another carb.
LT80 - do you have a used carb? Send me a PM or email if you do.
Has anyone tried the aftermarket LT80/KFX80 that is being sold on Ebay? It is supposed to be a direct replacement for the OEM.
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Apr 5, 2010 | 09:30 AM
#8
Thread Starter
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Trailblazer
Joined: May 2006
Posts: 45
Likes: 0
Update
I got a used carb. Went through it and made sure it was clean & clear, replaced any parts that were worn (valve & seat) and set the float level.
The LT80 runs great. After a few days of the daughter riding it around the yard, it started the same crap! It runs great when she is riding it. It seems to idle well. You can start it most of the time after you have RECENTLY shut it off. The problem rears it's ugly head when it has been sitting for a while. It refuses to start. I verified that I have spark (plug not fouled), the plug has fuel on it (wet). I had to hold it wide open and crank it for a very long time to get it to start.
Prognosis:
1. Is the Banshee fuel petcock causing this trouble? Should I go back to the vacuum operated petcock?
2. A while back, I removed the rubber boot that goes over the main & pilot jets. It kind of seals the jet passages to the bottom of the carb. Could this be causing my trouble?
Your comments are appreciated.
The LT80 runs great. After a few days of the daughter riding it around the yard, it started the same crap! It runs great when she is riding it. It seems to idle well. You can start it most of the time after you have RECENTLY shut it off. The problem rears it's ugly head when it has been sitting for a while. It refuses to start. I verified that I have spark (plug not fouled), the plug has fuel on it (wet). I had to hold it wide open and crank it for a very long time to get it to start.
Prognosis:
1. Is the Banshee fuel petcock causing this trouble? Should I go back to the vacuum operated petcock?
2. A while back, I removed the rubber boot that goes over the main & pilot jets. It kind of seals the jet passages to the bottom of the carb. Could this be causing my trouble?
Your comments are appreciated.
Apr 6, 2010 | 08:42 AM
#10
Extreme Pro Rider
LT80 Expert
LT80 Expert
Joined: Mar 2001
Posts: 8,340
Likes: 33
Hrumph...
Wet plug and full throttle to start is a flooding issue...
Did you shut the fuel off when you stop it?
I think I'd run it and when you stop, pull the fuel line off the carb and see if it still floods.
Smething stupid,,try closing the gap on the plug a lil.
Wet plug and full throttle to start is a flooding issue...
Did you shut the fuel off when you stop it?
I think I'd run it and when you stop, pull the fuel line off the carb and see if it still floods.
Smething stupid,,try closing the gap on the plug a lil.