Ok,

My sons LT80 starts and runs fine for the first 30 minutes and then it will go into a limp mode on me. It will only run with the choke on and about 20% throttle.

I just can't figure out what is going on with it. Would it be a plug? Why would it run perfect for a while and then go flat and won't take any throttle?


Thanks,

Troy

 

Could be a bad tank vent, you are building up vacuum and it prevents fuel from getting to the carb, try opening the tank cap next time it happens and see if that helps.
Another thing to look at is spark, 30 min, its all warmed up, could be the stator has a cracked coil or wire that opens up when heated, making you run bad, pull the plug and check for a good blue spark when cranking it over next time it runs bad.

 

For 3 bucks, you try a plug.
Clean the carb and do a compression test so we can eliminate those aspects of the problem. "choke on" can point to one/both of those.
If need be, then we'll go on to electronics.

 

Ok, I checked the gas vent, plug and compression. All are good. I have not cleaned the carb yet. However, I just don't understand how it can run "perfect" for 10-15 minutes and then start to bog out when you give her throttle. What could be happening?

 

It could be a electrical problem. I suspect the CDI and/or coil.

 

LT80,

I would be a fool to question your greatness because I know enough about your knowledge to understand you are usually right. However, can you please explain to a novice how a CDI/Coil that goes bad do so only after 10 mins of riding? Again, it usually runs 100% perfect, then starts to bog. It did start the other day and bog immediately, but that is not the norm. Btw, it does start perfect...no issues.

How would I start to look down the CDI/Coil path....I'm afraid this problem is getting above my skill set.

Frustrated.

 

Hey, question away! I surely can be wrong.
Sometimes electronics heat up and quit working.
I know you can test the electronics with a ohm meter.
Better ask Lynn Edwards. He's a electrical wizard.
To be honest, this could be a piece-o-crud floating around in the carb bowl. I'd clean the carb before I went much further.

 

Sounds good....I'll be hitting the carb here asap. Thanks again. I'll try and update you when I get her going correctly again. I was thinking....could it just be a case of bad gas? But then I thought, why would it run perfect then bog out if the gas was bad right?

Thanks

 

basic things to do in a case like this are clean the carb, clean the air filter, change the plug, and maybe drain the gas and put fresh in it. after that if it still runs funny, do a compression check and check the reeds, then all the "simple" things are gone thru, then everyone can help narrow down the more uncommon things that can be causing your issues, could be the stator warming up and going bad, but why go thru all the ohm meter checks and buying parts before making sure the air/fuel is perfect before that