Polini Thor 200 - Problem with RPMs between 5000 and 6000

[Pablo Azorin]

I'm having some troubles to keep the rpms stable between 5200 and 6200 rpms in my Polini Thor 200 Evo.

I tried replacing the Walbro carb for a FreshBreeze Bing carb, but nothing changed. The engine works properly in the whole rpms range except from 5200 to 6200.

For instance: with the the engine running at 5000 rpms, when I add a slightly more throttle nothing happens. I add more throttle and nothing. And then I add a bit more, and it suddenly goes to 6200-6300 rpms. The same on the opposite way. After take-off, I climb at around 6500 rpms. When I want to cruise, I reduce the throttle just a little and rpms drop to 5000. It's almost impossible to keep it somewhere in between 5200 and 6200 rpms.

Is this a common problem on this engine? What can I do to resolve this issue? 

Edited August 2, 2017 by Pablo Azorin

[admin (Simon W)]

Hi Pablo and welcome to the Paramotor Club  

The latest thing that I heard (from someone who knows more about the 200's than is healthy for a person... is that the exhaust port has a raised area that needs filing off. (porting and polishing) 

You may also like to read through this thread if you have not already

 

SW

 

[Gredford]

I like your time to comment on this place.

[WIlly]

Please check out my fix for this. Simply closed the mixture screw. And open 1 & half turns, run the engine for 5 min and check the plug. There are plenty of pictures online to show you if it’s running too lean and adjust the screw 1/4 turn at a time.