OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Powertorque - What are these?

Thanks Nolan at the moment the scrap metal bin at the tip is looking the best option at the moment

Does anybody know the principal behind these carbys as to what makes them work, seems to be lots of bits, were they a reliable carby

G'day Norm

You have asked a most interesting question.
I feel compelled to say something - as a non expert...

One of the features of the carby was less fewer parts.
I feel they are a 'reliable' carby ... but not a 'performance' carby.

I have just updated the record on the G4 carby.
I know it needs more work and input.
I feel it was revolutionary ... but a compromise in terms of performance.
Adjustments were limited.

G4 Carby Design and Bulletin

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Jack

So, the engine speed is preset at the factory. the tube at the rear of the carby that connects to engine block is the governor.

When the fly wheel speeds up, it creates an increased vacuum in the cap above the carb so the diaphragm lifts and closes the poppet valve just enough to reduce the fuel air mix and the engine reducing it back to the preset throttle position. When a load is imposed on the engine it slows the fly wheel down reducing the vacuum in the carby cap above the diaphragm. The spring in the cap above the diaphragm forces the diaphragm down to open the valve and allow a greater amount of fuel/air mix in and so the cycle continues.

some people get touchy about calling it a "vacuum" and stress that it's actually "negative pressure", but the victa manual describes it as a vacuum so whatever. At any rate, it self regulates. That's my understanding anyway. Someone will probably correct me. You can adjust the idle speed I'm told with these carboy's, there is a thread on it on the web page here, I'll find it and post the link if you like. but from my understanding it only works on the full crank design, as that allows you to access the button and clip while the engine is running. The power torque the connection is down in a tight spot and not practical to access while the engine is running.

Hello Nolan
I think you've got the theory right (for my modest understanding).
But the rear tube would be for the decompressor, the front tube for the governor.

Yes. A later addition of the carby gave an idle speed adjuster.
I might add, also, the governor springs changed to accommodate differing
top speed requirements.

It's a clever carby, but not a particular efficient one. I guess.

---------------------
Jack

Personally I like a slide or a butterfly on my carbs, then you can see what is going on. I have one of these LM carbs that is obviously running super rich from the amount of smoke it is putting out

Hello Nolan
I think you've got the theory right (for my modest understanding).
But the rear tube would be for the decompressor, the front tube for the governor.


Sorry Cyber Jack, depends on which end you're calling front and back. The governor hose plugs into the "restrictor". I thinks that's what it's called on the diagram at the start of this thread. The decompressor gets plugged into the part of the carby which houses the puppet Valve head.

But then maybe I've been hooking them up wrong

The 'restrictor' is actually a small separate part fitted inside the governor tube, and is only used on a few models with low [2700-3250rpm] governed speed.

It's more correct to say that the governor vacuum tube goes to the carby diaphragm cap, and the decompressor vacuum tube goes to the engine side of the carby body.

Just as an update, today I used the Power Torque at the start of this topic, to cut a big yard full of kapock weed about 12 inches high, it handled it well but I would still like some throttle control when ploughing through this sort of stuff. As a result of this I am considering fitting a carby from a Villiers motor to one of these Power Torque motors so I can control the revs. Does anybody have any idea as to the strength of these motors compared to the earlier Victas bearing in mind these cranks are only supported on one side. I have a project in mind for one of these motors if they are strong enough

Still playing with and trying different things with these carbs and my question is regarding JB Weld and petrol. Does anybody know how resistant it is to petrol. I used JB Weld on the reserve tube on a motorcycle fuel tap many years ago and the owner has never complained that the reserve didn't work and he had to push the bike for miles so I assume it must be still holding ok. Any thoughts?

I haven't really use the stuff. The few times I have it simply didn't hold up. I did have one come in this year where someone had use it to patch the fuel bowl rim of a Walbro carburetor on a push mower. It had failed and clogged the jets. It simply crumbling off in small pieces and when I tested its hold it all fell off.

I ended up replacing the whole carburetor with a reclaimed unit from a new mower that another customer ran without ever putting motor oil it. There was a large in the side of that engine for some reason.

I use JB Weld nearly every day on so many things, usually with good results,and there is several types of the stuff. I guess the best way will to soak something I have JB Welded together in some petrol for a week and see how it hold up.

Well I have just wasted 2 days trying to modify a G4 carb so I could get it to work the same as I do with the modified LM carbs. I have tried and tried to get the idle down to where I wanted it to sit but no matter what I did the idle would not lower. Finally I admitted defeat, and I put on an untested modified LM I already had sitting there and inside half an hour I had swapped them over and it now works perfectly. I cannot understand why I can't get the G4 to perform the same as the LM's. I kept trying because I believed I could master it but I admit defeat on this one. I have another G4 here so I will eventually have a go at that one to see if I can get that one to work

I use this for repairing plastic. with great success... Strong & easy to file/sand to shape/fit.. but this was with Rc fuel (Nitro)

[color:#FF0000][size:14pt]Q-Bond[/size][/color]

Thanks Paul, any idea how it handles petrol? I don't think it would , I haven't used Q-bond for probably 30 years, I had forgotten about it

Not sure & I have none left to try out.. Q-bond uses CA glue & the only way to dissolve it was Acetone ( nail polish remover ) I use it to remove rubber tires from Plastic rimms that I've glued on with CA glue..

Hi Paul, I'm not wanting to use it as a glue, I want to use it to build up three small sections on the carby cam on these where somebody at Victa went on a long lunch and came back to the drawing board with this stupid notch in the cam when you move the throttle back to the stop position. It is all well and good for the spider to drop down, but then to get the spider to lift back up is often impossible and this can then either pop the cable out of its locating spot or bend the cable. One of the Victa design mysteries. The other is this bizare rusting of the bases in the left hand top corner where the handle bolts on. I guess if you make a tough motor, you have to build in another weak point in the machine, otherwise nobody would need to buy a new mower. That is bad for business. This is obviously why there is always new Victa bases for sale on ebay, but at the prices they want, I would be surprised if the ever sold any

It's what Q-bond use as the binding agent for the plastic filler powder in the kit..