OutdoorKing Repair Forum Forums Finding and Swapping Wanted G3 carby

Tired of stuffing around with the old one, am after a G3 carby with governor attached.

If you like you can send them here and I can put them on a running mower and see how it goes.

Yeah might do that but mine will not work, there's either still a blockage (unlikely because I've cleaned it 3 times) or the float mechanism is faulty.

Well I'm happy to give that a go if you like.Just give me a PM if you want and we can work out the details.

Just remember the jet because. its 125 cc

Well that's OK I will be trying it on a 125cc.

Try these steps for the G3 Carby:

1. Check main 'O' ring on the brass jet.

2. While main jet is out check that the two holes are clear.

3. Make sure that the seat has not moved otherwise it will flood.

4. Check governor vane is in the correct position.

Once you explain a bit more I will give you some more tips to fixing a G3 carby,

Thanks Bruce.
Carby appears to be flooding as plenty of petrol around where the gasket separating the 2 parts of the carby is. The tickler mechanism releases a lot of petrol and it goes everywhere, hard to tell whether petrol is leaking from gasket or overflow from tickler.
1 o-ring appears to be fine
2 2 holes are clear as they have had carby cleaner put through them as well as compressed air as well as thin wire.
3. Did take the seat out for better cleaning, feels firmly back in but how can i be sure?
4 governor works when i move the vane but when i move the throttle, the butterfly valve sticks, cannot see why, how is governor vane to be positioned?

Any help appreciated as i think i'm close but mower starts and dies after a couple of secs.

tiger,


The reason that your are getting fuel leaking is because:

1. The seat is not sealing properly and this can be caused by the the float having fuel inside it.

2. Needle and seat damage.

3. Your fuel release primer is touching the float causing it to stay open.

Once the fuel issue is fixed you should have the mower running properly and if not we will look at the governor issue next.

Thanks Bruce, pretty sure float is ok ie no fuel inside it, have inspected it for leaks, cant see any.
Point 2, how can i make an assessment on this or do i just replace both of them?

Point 3, can anything be done about this, perhaps twist the tickler slightly away?

Had another look at the carby, the o-ring had a slight flat edge so i replaced it, also lapped the carby faces, had to use the same gasket because all the mower shops were shut. I tried to start the mower but no success.

Well the offer still stands.As I have no ideas left.

Appreciate it but i think i might be closing in on the problem
Will let you know.

How to test the needle and seat you will need to remove the base cover of the carburetor and then turn it upside down with some fuel line on the inlet. Then suck on tube and put tongue on end of tube, if suction holds then the needle and seat are ok providing the tickler is not touching the float.

Note if the tickler it touching float the test is a waist of time.

Since taking the carby off again the mower will not start. Despite putting in some fuel into the spark plug hole or using start yr bastard (i know i shouldn't use it but it started and ran with this goo), i cannot get the mower to run. Spark plug is slightly wet so assume it's flooding. Let it dry out overnight , tried this morning, still did not start. This morning i put compressed air through spark plug hole, carby and exhaust hole (which was also wet). Still no start.
Bruce, tried the needle and seat test, seems to be ok, also from what i can tell tickler is not touching the float. Compression is fine, still getting spark at least on the outside, have to assume its still flooding but how long does it take before the flooding airs out?

i had one bought here for the same sort of thing , just kept pulling it for a while with plug out and lead away from fuel spray !!! left it in the sun a few hours and it finally chugged itself back to life , smoked like h#@&+* too for 10 mins and allgood . seemed they left fuel on so almost a full tank went through it . g3 it was too , the guy lost the small button on top of tickler and put a nut on it !!! so as bruce said , it was holding the float down a touch . still has a spark , nice and blue ?? , Dave

I've tried some further diagnostics, i had someone hold the fuel tap while i held the carby and manipulated the float. The needle was closing ok. I noticed though that the spindle holding the float came off easily. I had some brazing rod so i cut up a bit and its now a nice tight fit within the carby body. I reassembled it and put it back onto the mower. I pulled the cord a few times and left the mower out in the sun for a few hours and it started but died soon after. Tried a few more times and it ran for several secs, best result yet, the throttle had no effect on the revs and it sounded like it needed more revving but i couldnt give it any more because of the governor. I tried a few more times to get it started but it wouldnt. Now have i got a flooding problem or is carby blocked again?

it may have the jet out of a 160cc , causing the flooding. the fact the plug is wet means the crankcase compression is ok .

Interesting theory. Plug is wet but i don't understand how you can conclude that the crankcase compression is ok from that.

because as the piston goes toward tdc , the crank case is under vacuum fuel is drawn from the carby into the crank case , then as the piston travels down the fuel air mixture is compressed in the crankcase then as the port opening is uncovered by the piston the fuel sprays into the combustion chamber . no crank case compression no fuel will get into engine

Gotcha, thanks for the lesson.

Tiger,

I have one thing that I want you to do for the test.

1. Remove the muffler and air filter hose and make sure that you are in a well vented area and then try to start the mower as normal.

Once you have done that let me know what happens. Note do not us start you bastard when doing this and you might have to pull it over few times if you still have fuel in the crankcase.

Hey there Tiger I dont want to but into this, But when you said this.

"I noticed though that the spindle holding the float came off easily. I had some brazing rod so i cut up a bit and its now a nice tight fit within the carby body."

That nice peice of brazing rod that is such a nice fit now, does the float pivot on it properly?
and by the way the "spindle" holding the float is not designed to be tight, the bowl on the carby holds it in.
Just my 2c worth, good luck.

Hi Bruce,

Have been practically operating under these conditions ie muffler is not well attached as only one muffler rod is on the engine and I don't have any muffler clips. Air hose is borrowed from a spare powertorque, not a great fit but best I can do for the moment. I will try the test as you described and let you know.
By the way I replaced the gasket in the carby. Also got the governor working properly and now the butterfly valve responds to the throttle cable. Spark plug is slightly wet but still sparks outside the engine, if there's a spark is it still considered flooding?

Jonesy, don't consider this butting in if it helps. Actually cut up another bit of rod that wasn't such a tight fit, I've realised that the bowl does the job of holding it in. Unfortunately the mower still will not run for more than a few seconds at best.

Tried as you suggested this morning, no change in mower's behaviour, did not even sound remotely interested in starting. Pulled the cord 30 or 40 times. Did notice that there is petrol on the engine outlet to the muffler.

Might not be a carby problem. I'd take off the carby and muffler,get a torch and look at the bore. Especially on the muffler side,see if it has makes in the bore. With what you can see of the rings see if their is any cracks in the rings. Sounds like one I had a few years ago would start if I gave it fuel but wouldn't run. Turned out it had scratchs in the bore and both rings where cracked.

I've started thinking that too but i looked at the piston on both sides and they're not too bad. Rings move freely, no sign of cracks. The carby now leaks badly and it seems to be leaking where the gasket is. I've replaced the gasket, lapped each half of the carby, changed the o-ring in the jet, ensured that the spindle does not foul the other half of the carby. This leaves the float/needle which seemed to work outside the carby. Spark plug i think is too damp as well, stick it in spark plug hole, no priming and is still pretty damp. I'm ready to give up

Have checked the top and bottom crank seals? Perhaps they are leaking. Failing that maybe start taking pictures maybe we can see what's wrong.

Have not investigated these seals, do I need to disassemble anything to get at these? I noticed a bit of a wet spot underneath the crankcase but there's plenty of fuel there which I assumed came from the flooding carby.