Scooter motor.
Recently replaced:
ECM, three coils, rebuilt carbs, replaced fuel pump, oil pump, New plugs/wires.
Starts fine, idles fine, accelerates hard, will run 4,000 rpms all day long, never a problem. Push it a little harder and it'll run fine for a random amount of time, then choke down on two.

Here's where I'm confused where to start:
It idles, and won't run right again UNTIL I turn off the key and let it sit for ten seconds, then start it up and it'll usually catch up and run like a champ again, IF I don't run it hard.

Dang ol' motors.....

Fuel supply issue. Either bad primer bulb, restrictions in fuel hose or bad pick up in tank. Cannot keep up with demand at high rpm.

Sure sounds like fuel, but Goff seems like a pretty savy guy. I'm sure you checked all that. is it a built in tank? Nothing in the filter.

It sounds like Pat has changed everything related to fuel except the fuel hose. If it's old and possibly not ethanol compatible it can be breaking down internally and collapse and you would never see it. Happened to a friend of mine on a three YO Crestliner.
I would try to borrow an external fuel tank and connect it directly to the motor and see if the problem goes away. That would at least eliminate bad fuel line and dirty pickup screen.

Sure sounds like you have something hindering your fuel supply to one of your carbs. I had an old Merc in-line 6 that did this exact same thing, ended up finding a chunk of hose lodged in the inlet to one of the carbs. Got it out and it ran like a top. I�d start at the carbs and go through the fuel system back to the tanks.

Fuel system is brand new from tank to motor.

If I thought it was fuel I wouldn�t have bothered anyone here.

What has me baffled.
Only after I shut it off and let it sit for ten seconds it fires up and takes off like a champ.
If I don�t shut it off it�ll never catch and run.
I would have guessed a coil was breaking down at rpms but I replaced all three.

I have a lot of respect for your post Pat a little scared to even try a response. But here are two possible scenarios stopped up fuel vent or carb float set to low. Have you pulled any spark plugs to get a reading on how their burning.

Yeah I�m gonna pull it all apart tonight. Was hoping I got a �your hematron wire is loose�.
Thanks for the advice I�ll let everyone know what the culprit is.

Pat.
Check your Hematron wire connection while you're in there.
Could be one of those "new" coils. I know they're new, but... JS. Frustrating as heck when you figure out a new part fails immediately. It happens. Good luck & hope its a simple one once you find it. Damn the gremlins!!!

Well....pooo.
I replaced the fuel connector, inside fuel line, put another filter on, it's not fuel.
Fuel pump is working fine, all three carbs are vaporizing fuel at WFO just perfect.

Now it's the electrical gremlin. I have another coil, I'll see if I can swap them around and try to make it fail, but we'll see.

Hope you're feeling better too. Its prolly a feel bad gremlin that'll only show up when you're sick. Strep gremlin. Damn him!!! Like I said earlier, I HOPE it's a simple one. Get well soon . Both you & your mota!!

Thanks.
I've got three more rabbit trails to chase down. I'll let everyone know when I find it.

Pat's been awfully quiet. Wonder what's happening with his motor.

It's sitting there waiting for me to pay attention to it.