OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines The G3 carby

Thought I'd start a thread on this that hopefully serves as a reference for the G3 carburettor. I've been doing up a Victa 2 stroke Mayfair with a G3 carby. I attempted to clean it and took off the bottom part of it and soaked it in carby cleaner. The top part was still connected to the throttle cable and the governor unit (I wasn't sure how to get these parts off) so I sprayed carby cleaner into all the orifices, took off the float, checked and cleaned the needle. Then I put compressed air through all the vents. I reassembled the whole thing and then tried to start the mower. I turn the fuel tap on, hold the tickler until I can see some fuel from the hole below the tickler. Then no matter what i set the throttle on, it doesnt start. Then i put some petrol into the spark plug hole and it runs for approx 45 secs obviously burning the petrol that's in the system as i had shut the fuel tap off as soon as it fired up. Turned the fuel tap off because i cannot get the kill switch to work on this mower. Maybe I'm using the tickler incorrectly but why is fuel getting to the carby and still not running? Couldn't find much on the G3 carby so hope that someone here can fill in the missing information.

I'm sure some of the G3 experts will jump in, but if you dont turn the fuel tap off does it run normally? Does it restart after it's warm or is it still difficult to start?

It does appear to run normally if I don't turn the tap off.

Haven't checked it in the last couple of days but when I did was still a little difficult to start when it was warm.
Got me a litte stumped, there are no diaphragms in this carby, looks basic but for some reason the fuel is not being sucked into the engine at start-up.

Have checked the mower tonight and again it did not run at first. This time I dipped the spark-plug in some petrol and put it back in and it ran. Turned it off twice and it started first time each time. My conclusion is that the engine is not getting petrol but the tickler is producing a flow of petrol so what gives?

sounds like the jet is still a little blocked .
ill post the pipe this week sorry for the delay

Yeah Mitch, can see why you would draw that conclusion but I was so careful when I cleaned the carby, I used carby cleaner and plenty of compressed air.

Can you remove the float bowl from the carby
and take a picture of the float some can be slighly
adjusted

The float bowl is very close to the chassis so will have to remove the entire carby to get a picture but I'll see what I can do. From memory though I couldn't see a lot of adjustment possibility, there's a rod that the float swings on. The rod looks like some brazing rod.

Did you pull the little brass jet out and clean it or just leave it in there, I have found sometimes crud can get stuck under the jet.

Also if you choke the motor while pulling the rope will it attempt to start? Its been an old trick I use if its a minor blockage the extra suction will generally remove a partial blockage. Also I found a lot of these engines really like a snorkel attached, without they can be a bit piggy.

Thanks Joe, I don't think I did take out the brass jet. It doesn't seem to matter how much choke there is, the sound is the same. Take your point about the snorkel but even with what I've concocted the motor does start with a whiff of petrol. Could give the carby another clean but this time I'd like to take the governor bits off, is that easy to do, ie do they just screw off?

really no need to take them off and risk damage unless you havto though . just a good clean should do it . did you use the throttle and look to see if the butterfly i opening and closing ? they really are a simple carb , almost always just a blockage or water but seems you have taken care of that , just take out the jet and clean again . might have missed a bit of crud because it dont take much

Thanks Vccomm, I didn't really want to take the governor off because you can never be sure you'll get it back together again. With other carbys I've done I always give them a bath and that way I know I'm getting all the crud out. I didn't do with this one because the carby cleaner may have affected the plastic governor. Butterfly is opening ok, will have to look at the jet but thought if I'm going to take the carby off again I'll give it a good clean.

and as joe said , you need a snorkle of some sort too or restrict it in some SAFE way . they really need it , or they sort of backfire and mess around a lot

Have got a snorkel of sorts, not as good as the original but close, muffler is only just holding on as no engine rod to put the clip onto, will have to improvise.

if the little steel rod is gone it either rusted away (unlikly)or the barrel has been removed ? so maybe a broken or missing base gasket in which case it wont run for long i think . but even without a muffler it should still start n run get dont annoy folks with it !!!

Sounds more like it's a 125cc and they have rods to hold the muffler on.If the clip breaks or falls off the rod can quite easily fall off.
Here's parts list for the G3.I guess make sure you have all these bits.

Thanks Blumbly, you're right about the rods, there was one on the bottom but the top one was missing and I think you're right about it being a 125cc too, I appreciate the diagram, I believe I've got all these parts but I still cannot get the kill switch to work.
I have taken the carby apart again and this time gave it a thorough cleaning using carby cleaner, air compressor and a thin wire to clean out all the orifices. Removed the brass jet and gave that a thorough clean too but mower still does not start. I may be off the mark but I believe that there is not quite enough compression to draw the petrol into the engine. It's a close thing and maybe putting some petrol into the spark plug hole provides just enough of a seal to get the engine going.

It really doesn't take much compression to start and run 2 stroke. If you can put fuel in the spark plug hole and it runs then it should have enough compression to run on its own. Maybe not the carby. Did you check the decompression valve it maybe stuck open and not allowing it to run on its own. Also check to see that fuel is coming out of fuel line,in a nice flow. Just pull fuel line off carby and open tap. Maybe the filter is blocking a little. You just have to go back to the basics with internal combustion engine. My formula (what I always say) is suck squeeze bang blow. Now we know it can squeeze band and blow,so we just have to work on the suck part. Don't give up you'll get it.

Hi again Blumbly, fuel line is fine, I cleaned the filter. I decided to take the decompressor valve off and replace with a spark plug, it started fine. The decompressor is the old style with the clips that you can take off. I assume the decompressor is faulty but not sure. It threads nicely into the cylinder but has a wobbl


e where its nut meets the decompressor body. Perhaps this is allowing an air leak? Photos show the decompressor and the float (for Tomo).

FROM BAD TO WORSE

Can rule out the decompressor, replaced it with a spark plug.

Checked for air-leaks, can't find any so rule that out.
What happens now is that the mower starts, splutters for a second or two and then dies. The obvious diagnosis is that it is starving for fuel so I again clean the carby for the third time. There is no change in the mower's behaviour, it starts, runs for a second and then dies. The spindle that the float pivots on looks like some brazing rod, perhaps it is not quite long enough and slips off, I don't know?
Have spark, compression but still doesn't run, tank has plenty of fuel. Any suggestions???