I was wondering if there was a effective method for checking for air leaks?
Plug the carb throat and the exhaust outlet, connect a new, unused fuel line to the carb and blow into it and brush soapy water over the parts that connect to the block. Expect a little leakage from the front bearing.
The Super Derecho
Best to replace a leaking bearing than cover it up. The best way to tell if your bearing is leaking bad enough for replacement? Besides having a high idle and pretty much impossible to get a decent tune, you will find the back of your flywheel will be wet with clean fuel and probably it has slung fuel all inside the lid, and lastly some puddling under the flywheel on the chassis....
All Lives Matter
United We Stand, Divided We Fall
Nitronaught, I couldn't agree more. Masking a leaking engine bearing can get expensive when the engine is destroyed by bearing shrapnel.