Honda GX120 and GX200 how much timing advance?

[Quinc]

Looking at the timing advance Woodruff keys for these engines and wondering how much I can advance the timing and be reliable on 91octane? Elevation around 4500-6000ft is where i will be running them. *Noise level is a concern so want to keep exhaust and intake oem.

 

[Whitetrashrocker]

I wouldnt bother.
Unless your adding go fast parts, there's no need to advance the timing.

 

[panchothedog]

Advanced timing only helps when you are turning very high rpm. Like with a very hopped up engine. Your bone stock engine will probably run worse if you advance the timing. Especially so at lower rpm, or when accelerating from a stop, or trying to climb a hill. The engineers at the factory aren't stupid. Stock engines normally run just about perfect. Hopped up engines are usually a LOT louder than a stock one. If you need more power, but have to keep the noise level down, buy a bigger engine and leave it alone.

 

[Darren]

Engines are governed to a max of around 4000rpm, peak torque is around 3600rpm, engines are designed for efficiency and power at 3600.
If you remove the governor the engine will rev up to around 5500rpm, but the cam runs out of puff around 4500. If you want more power at lower rpm then increase the efficiency of the head, gas flow the ports and put a thin head gasket in it, this will give you a small improvement because the head flows sufficiently at low rpm.

 

[65ShelbyClone]

Looking at the timing advance Woodruff keys for these engines and wondering how much I can advance the timing and be reliable on 91octane?

For what purpose?

 

[Quinc]

Engines are governed to a max of around 4000rpm, peak torque is around 3600rpm, engines are designed for efficiency and power at 3600.
If you remove the governor the engine will rev up to around 5500rpm, but the cam runs out of puff around 4500. If you want more power at lower rpm then increase the efficiency of the head, gas flow the ports and put a thin head gasket in it, this will give you a small improvement because the head flows sufficiently at low rpm.

Great Idea! I will see if I can find a thinner head gasket or high comp piston.