OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Commando Keystart Governor Spring?

Hi all, I have a 2003 Victa Commando Keystart CKS201K. Someone else in the family has meddled with the carby, so I’ve put a genuine kit through it, new primer cap on, and a genuine new correct fuel jet. The rest of the mower is near-new and all gaskets/seals etc are in good shape with no air leaks.

Can someone please advise me what the correct governor spring for this model is? It runs great but seems to run slower than what I recall in the past. Full actuation of throttle is confirmed and adjustment at both ends is spot on. The existing spring has no colour on it and I suspect has been incorrectly swapped out…. (not by me). I've worked on mowers and small engines for most of my life, but just lack the info for this specific model.

The mower is a 4 blade disc model and has the poppet valve set to “A” - based on a partial service manual I found stating that 4 blade disc models should be set to "A" and operate at a reduced RPM than 2 blade models. It’s an A3C/A4C marked valve from memory. Allegedly, the vacuum hose connected to the end cap on the carby has a restrictor valve in it for 4 blade models. If someone could also confirm that to be true, that would be great.




Thanks in advance!

Hi Charlie,

I've always just removed the side cap and stretched the outer spring put it back together and if it revs out too fast on idle
put a brass washer behind the cam and set the poppet on C , then I just control the RPM by the throttle control.

But correct Procedure is.

Governor Spring & Calibration
Spring Specification: The standard outer governor spring for a G4'LM carburetor is typically the red spring (Part No. CRO3417A), rated at approximately 150g tension. If an incorrect or stretched spring is installed, it changes the vacuum balance against the diaphragm.

Field Workarounds: While stretching the spring or inserting a brass washer behind the cam can force higher revs or adjust idle, doing so bypasses the engineered vacuum governing range, which can lead to unstable governing or over-speeding under load.

Poppet Valve & Restrictor Confirmation
Poppet Valve Setting ("A" vs. "C"): Factory specifications for 4-blade disc models indeed require the poppet valve set to "A". This restricts maximum airflow/vacuum response compared to setting "C", intentionally running the engine at a lower, safer maximum RPM to account for the heavier mass and momentum of the 4-blade cutting disc.

Vacuum Hose Restrictor: Yes, the vacuum line or end-cap fitting for 4-blade disc variants features a built-in restrictor (or a restricted nipple hole) to dampen the vacuum pulse. This prevents the governor from reacting too aggressively to rapid pressure fluctuations.



Cheers Max.

Thanks Max, I really appreciate your thorough information!