J Ridders 4 stroke I/C Engine

I have constructed a J Ridders 4 stroke I/C single cylinder. I can only get it to fire for two or three strokes before it stops. Does anyone have any advice on carburation. I believe the electrical timing to be correct. Any advice, possible errors or ideas would be welcome.

Edited By Peter Hadley 1 on 05/12/2018 10:36:28

Old Adage: Most carburettor problems are electrical. Is than an old Lucas motorbike spark coil? If so is it set up for positive earth in the Lucas manner? Likewise condenser. Has it been proven to be a good coil? They are notorious for playing up.

Have you tried squirting a bit of petrol or ether spray down the throat? Should at least fire up temporarily if all else is good.

I can't quite see from the photos but are you using a vapor carb or liquid fuel, Most of these models are very sensative to the mixture needle which is more like an on/off switch than a fine adjustment so easy to flood them. The vapor carb is what Jan found worked best on this one.

Is that motor being used as a starter? if so you want a way to take the load off as the engine starts, a cordless drill is the more common way to power start them with a simple dog drive though I usually flick the flywheel over by hand. If it is being used to generate then take it off until the engine is running sweetly.

Is the compression good? You should be able to 'bounce' the piston off the compression.

Best regards

Roger