21 hp Vangaurd loses power when hot
Vangaurd 21 hp #385777 / 0349E1 / 04012811
Starts easily and runs strong for about 5 minutes. It will suddenly lose power and sound as though the motor is struggling. Turn off the blades and sounds like it is running fine. Not smoking. I have searched the forums and done the following:
1. Checked all pulleys on deck
2. Cleaned carb with compressed air
3. Re-set the valves
4. Checked fuel flow
I can't visually see anything wrong with the valves or rods. The engine has about 300 hours on it and has been well maintained with oil and filter changes.
I read on one of the post about 2 coils and maybe one going bad, but I can't even find a coil, maybe does not apply to this engine?
Any ideas would be greatly appreciated and thanks in advance for your help