OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines 3.5hp Briggs No Throttle Response

Hi all, I have a Victa that has a 3.5 Briggs motor on it, it has the plastic governor flag and the governor spring and anti-surge spring type. This thing starts first time but has no throttle response, runs full revs all the time. I have replaced the governor spring and anti-surge spring, I have adjusted the post that the anti-surge springs fits on to, to a back and forwards position, but that doesn't change the revs. The springs are fitted correctly and the fuel tank clip and rubber seal are in position when the tank is fitted. Any ideas?

I need the Briggs model and type to better diagnose the problem but it can be one of three possibles off the top of my ead.

The governor flag binding on pivot point or mouse bed under the shroud preventing air flow.

Many of these carburetors have a plastic throttle vane shaft that can stick due swelling or old fuel residue.

or the throttle vane itself just is missing. If missing then you need to find it as it is most likely sucked into the engine and can cause damage.

Thank you, appreciate the feedback. I just finished tinkering with it again. I've changed the carburettor totally, put in a new diag. and gasket, new "o" ring, new rubber elbow on the carby, new gasket on air cleaner, new governor and anti-surge spring, checked the plastic manifold tube for cracks and tightness, put it back together and it still does the same thing. One thing I did notice that when assembled (not running) and the throttle slide is set to fast, there is little or no spring back on the governor vane. It is the 3.5hp Sprint motor.

If the flag moves freely then there is too much spring tension, it is a balancing act between the pressure on the flag created by the fan and the tension on the spring

It normal for it to have the throttle vane open at rest but as NormK note you do need to have the correct springs installed.which why the Model type and date code are needed when looking up parts as there various setups and not an one size fit all springs

Finally, found the problem. Last thing I would have thought to look at. Someone had replaced the coil with a non B & S one, looks like a Honda. What was happening was when you throttled back towards idle the governor flag was catching on the corner of the coil preventing the throttle from coming back to idle, after trimming a small amount of plastic off of the inside of the governor flag the issue ceased to exist and it is now running properly. Who would have thought.