Hi from newbie,

About a month ago I bought my kids a used LT80. Great little machine, but soon started developing a problem starting it.

I am a real novice at this so please bear with me - any help you can provide will be much appreciated. I will try to describe...

The engine turns over fine. I normally use another battery to jump it which is kept fully charged - so think iI can eliminate battery.

I get an ok spark at the plug - so I guess electrics are good. Spark plug looks ok - no build up of oil reside - but is dry - ie. no unburnt fuel.

Problem really started after fuel tank ran dry. Led me to think could be blockage in carb. Took carb off and cleaned (in a very amature way). Some debris but not too bad.

Fuel comes down frm tank freely when fuel switch on prime - but no fuel comes out when on other two positions. Is this the problem?

Haven't done compression test yet. Is this the next step?

Please help
D.

 

Welcome to the forums.
It's a vaccum operated petcock. It won't flow till the motor turns over.
Did you remove both jets and the float needle and seat and clean all well?
Try sticking 2 fingers in front of the carb to hand choke it.
Checking the compression wouldn't hurt.

 

to test the compresson if u dont have a tester put ur finger in the plug hole when u turn it over it should suck ur finger tight then push and you can tell if it has enough to run if you have the skill to make it that far youll tell but sounds like a dirty jet

 

Thanks very much for your responses.
I tried turning the engine over while checking the petcock - and there was no flow - do I need to replace it?
I did not remove all the carb bits - like I said it was a very amature attempt at cleaning it. Looks like I will have to strip it right down. Maybe I should get a refurb kit at the same time.

I am away on business now until Friday so it will have to wait till next weekend now.

I'll pick this up then and let you know how I get on.

D..

 

I'm having the same problem with my son's LT80. It ran fine for a few months, then it sat in the garage for 2 months. Something leaked and left a puddle under it while sitting for so long. Not sure if its gas? Never leaked before when he road it every day. Went to start it today, it turns over great, but doesn't seem to be getting fuel. Pulled hose off petcock and it was dry. No fuel in hose. I put some fuel in the hose and tried to start it. It fired up for a second and died. Do I have a bad petcock? I'm not familiar with these vacume type petcocks.

 

It needs to run to make enough vaccum to open the petcock diaphram.
After a rebuild (and most don't need a kit) you turn the petcock to prime to fill the bowl.

Sleddhedd:: Welcome to the forums.
I think your motor filled with fuel and has leaked out. Remove the spark plug, put a rag over the hole and spin the motor over to get the fuel out. You may want to leave it dry out a lil while. Clean your carb then when trying to start, apply full throttle till the motor starts and cleans out and revs up.

 

Well I spent the day on stripping down the carb etc today - and still no joy starting.

I cleaned out all the jets on the Carb. very careful not to disturb float levels etc. but stripped it all down and cleaned thorougly.

Now when I turn it over there is definately fuel getting through with the choke on. Plug is wet with oily petrol. Not sure why it is so oily???

Did finger test on compression - and as far as I can tell it's ok. seemed to suck and push - but not so much that it gripped my finger too tight or pushed it out of the hole.

Very nearly catches - but just doesn't quite start.

Occasional backfire makes me think fueling is ok.

Spark still seems regular and bright.

Stripped out air filter box. Some mud and grass build up inside air box blocking pipe down to crankcase. Could it have overheated? What would have happened if it had overheated? how do I check?

Now at the end of my teather (and knowledge and skill).

Any ideas anyone?


Regards

 

Did you try the full throttle start? Hold the throttle open and try it.
The finger deal isn't too good of comp check. Better find a gage.

 

Well - found out the problem - no compression.
Head off revealed smashed piston rings. Must have had some grit in there somehow.
Getting rebored now.
Will update when I get it back together.
Dave

 

Not to thread-jack, but this info is VERY relevant to my situation. My LT80 doesnt have enough compression to start anymore either. What are my options to rebuild the thing, any cheap upgrades that can be done on the way back up?