Par car 1990 NO POWER

[Detlev]

My par car first ran good.
Then the sparkplug went out

Replaced it and it ran again. But with NO POWER.
The engine will not rev up. Runs smooth stationary.

Changed the piston rings and cleaned the carb.

But still no power and will not rev up.

Looks like a have enough fuel from the pump (puts out plenty of fuel when i run it in an jar)

Sparkplug is nice caramel brown and dry.

What can it be?
- wrong sparkplug?
-ignition (tried different settings but no change in power)
- no compression despite new rings?
- cracked case somewhere?
- carb still no good?
- thing after the carb broken?

I really am lost a bit so any help is welcome!

[backyard]

NGK BP4HS @ 0.035 in gap. Let the parts house cross reference the plug at your own risk.

Check your ignition timing. There is only one setting, not multiple settings.

Check the compression with a compression gauge. This is a valuable item to have. Maybe you blew the head gasket. Compression is the first thing you should check.

I doubt you have a cracked case but it is still possible.

Just cleaning a carb doesn't always guarantee it's clean. I can attest to that.

What thing are you talking about after the carb? You lost me on that one.

What oil ratio are you running after the rebuild?

[Lochlin]

You may want to make sure your clutches are operating right too. If one of them aren't opening / closing right it won't not allow your engine to rev up. It'll seem like an engine problem but it's actually a clutch problem.

[Detlev]

Thing after the carb:

The Reed Valve

[backyard]

Yes if your reed valves are bent or broken you will suffer a power loss. Though unlikely, the valves could have rotated allowing air to blow back out but you should be able to tell that by looking into them.

Do you have a compression gauge?