Has anybody also encountered a problem with the stock plug? Here is what happened with my motor: Out of the box it started up, but very hesitantly. It would run for a few seconds and then quit. This continued on until the engine would eventually warm up. After a while she would continue to run. I suspected the plug for being the culprit. Every time the motor was cold it would do the same thing; briefly run and then quit. So I bought a new plug and replaced the Chinese junk. Now it runs like a champ. Right from a cold start. No quitting anymore. So far I like this engine. Very little vibration, very low idle and plenty of power. We'll see how long she'll stay in service.

Is it one of the Torch Plugs, if so get rid of the plug and get an NGK, not sure of the number but someone will be able to give you the correct one here. Make sure your needles are set to run smooth also check for any seal leaks. Some CRRC engines seem to a little difficult at first and improve quite a bit once you run some fuel through them at least a gallon or so, do not run them over ritch like you would a glow engine. (you will never seat the rings if you do)

The Jenn Feng in my crrc 40 acted about the same way. I put in an NGK and it started right up and ran great.

These OEM plugs either work or they don't

Some work well and last a long time.

If your's doesn't work - get a NGK

The Jen Feng plug for the CRRC 40 and 50cc engines are the same, the NGK equivalent is a BPMR6F, or Champion RDJ8J. The numbers on the Torch plugs in the 26cc engines directly cross to NGK,use an NGK plug of the same number...CMR7H, CMR5H etc.

After buying one of the JUNK CRRC-PRO Gf50i engines, one of the first problems I had was I had to replace the spark plug that came with it. But that was one of only MANY problems that me and MANY others are having.

I get phone calls from the buyers of these engines having problems and they have learned not to buy them.