Timing or ?
 

30 years ago my engine was rebuilt. It took until today to try and start it !

It appears the engine blows air through the carb. Inlet instead of sucking air.

What to make out of that ? Timing issue ... valve clearance maybe. I am very confused.

Henk

Re: Timing or ?
 

Do a compression test, maybe stuck valves.

Re: Timing or ?
 

Remove the sparklers and squirt in some oil. Turn the engine over a few times. Squirt in some more oil and let it sit overnight. If that doesn't do it then you may have to remove the side cover and un-stick a valve or 2.

Re: Timing or ?
 

Use penetrating oil or MMO.

Re: Timing or ?
 

It could be the camshaft out of time but after all the years, it definitely could have stuck valves. If you could source Marvel Mystery Oil, I'd recommend that but where you are may require a substitution. Automatic transmission fluid mixed with acetone is a good substitute.

Re: Timing or ?
 

Stuck inlet valve. Pull spark plugs and squirt in some MMO on the valves. Let sit for a while.

You have been waiting 30 years, what’s a couple of days more.

Put some MMO in your gas. Really helps the valves.

Good luck.

Enjoy.