OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines LM carby

I pulled an old Mayfair 2 stroke mower out of the shed, late sixties, maybe early seventies, looking at it it probably hadn't been started in 20 years or more. I checked it had spark, fitted one of my modified LM carbs on it and on the second pull it started, ran and idled perfectly as if it had been used yesterday. Can't do that with any of the Chinese junk, leave them sit for a couple of months and you often have to replace the carb or just throw it out

Good work NormK, totally agree with you. Any tips for the G3 carbs, I haven�t worked on them much and now I have ended up with quite a few mowers with these fitted. They seem to have just an idle or run response not much in between.

Sorry Paul haven't had a lot to do with the G3's, any that work I use but now that I can fit the G4/LM to them it is just so much easier and parts are readily available for them and the G3 is getting harder to find bits. The LM type will still be around for years to come. I am not restoring mowers so having the correct carby is not a problem to me, I refurbish them so they can go back to doing what they were designed to do, cutting grass

Thanks Norm.

I don't know why so many worship them like Baal. Fiddly little things where you need a degree in rocketry to rebuild them. Sometimes there is something to be said for plastics and Norm had shown us the way.
Any home handyman can dismantle them and put them back together. Ok the throttle cable may stump some but simple observation will guide you eventually.

Hi Mowerfreak and NormK,

I don�t have an issue with plastic carbs, I can rebuild them in my sleep. I was just asking about the G3 carb and the lack of a rev range.

The G3 throttle butterfly works off the flag and the force put onto it by the flywheel fins, the only mechanical force is applied via the cable to the lower spring mount which in turn applies more or less tension to the governor spring.

The spring then dictates how much the flag will move under air pressure from the flywheel, this works for idle and cutting revs but not much in between. I was just asking if Norm had any experience with the G3 carb.

Hi Paul in answer to your question yes I have modified G3 carbs, cut the flag off and been able to get them to operate via the throttle, bit of a messy job trying to lock the throttle shaft to the flag base but I have done it a few times with reasonable success but as I said not for the person who wants original.

The governor spring tension is adjustable on these, and does affect part throttle response somewhat, as well as idle and full throttle speeds.

First of all, check that the butterfly moves smoothly through its full range, when the governor flag is moved back and forth. Then check that the flag is correctly adjusted - it should be at 90� to the carby bore with the butterfly closed, with the flag on the same side as the fuel inlet. It's not unknown for the plastic gears that link these parts to slip a few teeth.

If these items are OK, try adjusting the governor spring tension a few clicks at a time, by turning the seating ring ['tension applicator'] at the lower end of the governor spring. There should be a spring clip locking the ring to the main 'throttle connector', and this has to be removed to adjust the spring.

Details are given in a workshop manual excerpt in Part 4 here: https://www.outdoorking-forum.com.au/forum/u...ne-parts-list-and-manuals.html#Post54967

Thank you Gadge, NormK and Mowerfreak. Very helpful.

I always found the G4 set up gave the engine a high tech look, even if it was mostly an illusion.
The metal carby looks old fashioned in comparison but makes the engine sound abit more lively in character. The red tickler is definitely the highlight for me but squirting fuel onto the deck does look crude and would be totally unacceptable these days.

I took one of my Victa 24's up to my grandsons block because the council was on his back. This is one is an early full crank with the G3 inlet spigot on the barrel that I have fitted a modified Powertorque LM inlet spigot to. This was to test it out to see how it performed and it worked faultlessly. Always a good feeling to have a little win every now and then

BTW folks, the ODK Shop seem to have more G3 bits than anyone else around these days; https://www.outdoorking-forum.com.au/index.p...amp;inc_subcat=0&sort=20a&page=1

While they last, at any rate.