First let me say thanks to all those with knowledge who share it here. Second let me say I've looked at a lot of posts about ET4's that won't start but none are quite like my situation. (I have no experience with scooters but work on all my cars myself) The post is long because I wanted to get as much detail in as I could. Here goes:
2002 ET4 150 Leader engine, Walbro carb. 1400 miles. Bought recently from a friend. Had been stored for approx 2 years. Like new condition. See picture.
Gas drained before storing so no bad gas issues.
I took it to a shop & they wanted $1100 to do all kinds of stuff to it. ($70 just to look at it. $95/hr shop rate seemed like a lot to me). That's more than I paid for it and from everything I'd seen online that made no sense to me.
Took it home (last week). Put a new battery in it. Put 87 octane gas in it but added a bottle of octane boost when I realized it's supposed to get 91 octane. Only filled to about 1/2 tank so I don't think I flooded the evap canister. It started & idled but would die when I tried to throttle it up.
Removed & cleaned the carb after watching you tube video. The last person to disassemble the carb had used blue gasket seal in addition to the factory gasket on the float bowl. I had to use air pressure to "blow" the float bowl off. Some of the blue stuff had gotten inside the bowl. I cleaned all of it I saw. Idle jet was blocked. Got it opened. No tears in diaphragm. It started & I rode it several miles.
Noticed it hesitated a lot on acceleration and when coming to a stop. Ran GREAT when on main circuit.
Cleaned the carb again & sure enough the idle jet was clogged again. Cleaned more blue stuff out of the bowl. Put a new spark plug in. Turned the idle screw to raise the idle a bit. Started & idled fine. Rode several miles but still hesitating (maybe a little better than before).
Cleaned the carb again. Idle jet clogged again. More blue stuff. Was extra careful to get all of the blue stuff I saw this time. Tried to get the floats out so I could get under them to make sure there was no more blue stuff but the pin wouldn't come all the way out so I tapped it back into place. Floats still move freely. Diaphragm still good. No changes to air/fuel or idle speed settings this time.
Put the carb back on. Started fine. Rode about 100 yards & died. Haven't been able to get it started since.
Turns & turns but won't turn over. When it does seem like it's about to turn over, it seems to backfire & then goes back to just turning. Makes me think the carb is rich. Have checked the jets & diaphragm again. They're good. Battery is on tender. Turned the air/fuel mix to 1.5 turns from seated which I think is just a little on the lean side. Set the idle speed to as low as it will go. Still won't start. Plenty of fuel coming out of the fuel line when disconnected, so don't think it's the fuel line. When I take the carb off, lots of gas comes out.
Checked the air filter & it literally disintegrated in my hand. Will replace it but have been trying to start it with no air filter in place - still no luck.
Did notice that fuel flows freely from the fuel line when it's disconnected from the carb. I think I saw that it's not supposed to do that (fuel only supposed to flow freely when vaccum is applied to the petcock, opening the valve?). Put my hand over the intake side of the carb when trying to start it & my hand was very wet with gas. Again, think that makes it look like the carb is rich(?)
I'm at my wits end! Really disheartened. Thinking of taking it to the shop & hoping they don't screw me too badly but thought I'd try here first. Sorry for the long post but thought all the detail would be helpful.
Thanks for any help/thoughts.