85 Aero - hard to start, won't stay running

[tricolour]

I've got an 85 Aero that used to run great and I used it all the time. Now after sitting for a few weeks, it's very hard to start and won't stay running. If I put some fuel down the spark plug hole, it will crank for several seconds, and then it will finally hit and run very poorly, but barely running, even at WOT and then it will quit. Sometimes If I cover the carb intake for a few seconds and then uncover it, the engine would fire up but still just barely running for a few seconds. Here's what I've done so far.

NEW spark plug
Getting good spark
Removed and cleaned carb including all tiny holes
Checked exhaust pipe, not clogged up and removed for testing
Has good spark
Compression seems good, not tested with guage yet
Checked flywheel timing, looks good. No sheared key
Battery fully charged
No carb adjustments have been made since it worked fine before
Took the cylinder head off for inspection. Looked good, scraped minor carbon off piston.
Bore looks good, no scratches or seizing found
Exhaust port not clogged
Fresh fuel
Petcock/fuel valve working properly
Plenty of gas in the carb
I even tried putting gas/oil mix directly into the intake manifold, but the engine still would not fire up

What else could it be? I can get anything running, but this one has me stumped. Could it be the reed valves?

[Bear45-70]

Compression seems good means nothing. Get a compression tester and know for sure, because a low compression motor will never start and checking anything else before confirming compression good is a waste of time.

I have an 1985 Aero 50 on my bench right now that the compression seems fine (electric start only means you don't know) and the guage says 35 PSI and guess what? It won't start either.

[turtle13]

I second the compression test. However it sounds like your trying to run it without a filter. On these engines they require the airbox if not jetted properly to compensate. If it will try to fire with your hand over the carb acting as an extra choke it means its getting to much air.