OutdoorKing Repair Forum Forums Finding and Swapping Wanted G3 carby

I still can't get away from a fuel blockage. Have you checked the filter on the fuel tap,inside the tank? Maybe that is blocking the flow of the fuel. I think somebody should do some changes here as this topic was started in the wanted section,but has become a diagnosing and trying to fix topic.

On the face of it, it would seem a blockage but I have cleaned the filter on the fuel tap. Upon turning the tap, the petrol flows freely. Happy for this post to be moved into a more suitable area.

If it were a blockage it wouldn't be flooded

Good point. That leaves compression, have started to take off head but one bolt is difficult to get to, no room to get a socket into.

The motor will need to come off the base to remove cylinder

The condenser breaks down under load and you would need a tester to see if it is damaged. I don't care how new it looks it is the internal that could be the problem. In the past I have taken a new one off the shelf and it has been faulty.

What basically happens is that the engine will start and then within seconds the engine will run rough and can stop.

Unfortunately you are in the process of elimination trying to find the issue because you don't have the equipment for testing.

How did I know you were going to say that.

I have a multimeter, is that sufficient?

Tiger,

Not really because it does not show under load. The price of a condenser is only about $7.00. Also does the points have any pitting if so that is a sign that the condenser could be faulty.

No pitting, just curious as to what tool the pros use to test a condenser?

Have opened the Mayfair up and checked the bore, it is pristine except up the top where there is some very light scoring. It has not been re-bored. All suggests that the compression should be ok except that one of the rings has got a bit of movement. It's also definitely a 125 cc motor.

hey thats good news so far ! can you remove the rings and take a photo to post up.
ill send you a set of std rings i have here.
also once you have removed them sit them in the cylinder so you can see the ring gap and take a photo of that also

Great Tomo, I'm guessing that I need to separate the cylinder from the crankcase on this mower so I can take the piston out?

Hey , yes you will to get to the piston

Took the engine apart. The gasket b/w the cylinder and the crankcase showed a little bit of leaking, not sure if that is a problem and whether that would compromise the compression. Attached are photos of the piston and rings. Put both rings in the bore to show wear, the top ring had a gap of 2 mm, bottom ring was about 1.8 mm. Other photo shows how loose one of the rings was on piston.

For a true measurement of ring gap try a bit further down the bore from the top where it wears most, at most the rings should have 0.432mm ring gap and at least 0.203mm of gap evidently they are very worn, but very cheap to replace, even if new rings didnt come right within spec they would help the situation for a display/light duties mower anyway.

Hard to tell from those pictures but do the rings appear to be the same thickness all the way round? Also what condition is the bore in? May just come down to a very good clean.

Thanks Joe, if they are very worn it makes me wonder how the compression gauge recorded above 70 psi, anyhow will try to take a measurement further down. I know they're pretty worn because they came off the piston pretty easily.

Pretty constant thickness all the way around, bore is very good condition, are you saying to just clean the piston grooves and the cylinder bore?

Heck yeah I'd even go to the trouble of honing the bore.It would certainly help.

Can't hurt so will do, have a honing gadget with 3 stones here somewhere, think I bought it do brakes but never used it for that purpose.

hey there ,
those rings are rooted ! that gap is rather excessive a hone and some new ones certainly wont hurt it. ill post the hose and rings on Monday man.
should make a fair difference, give your piston a good clean , a light wet and dry to tidy up the scoring , and clean the ring gaps out, base gasket weeping is okay they don't often blow out base gaskets.
a light hone to scuff up the bore and and a good clean , also clear any carbon build up in the exhaust port.

Thanks, Tomo, I guess I'll need two gaskets, one for the head, the other for the crankcase, I'll pick those up at the mower shop, is there anything else I need? Do you think the worn rings account for all the problems I've had with this mower?

hey , yes you will require top and bottom cylinder gaskets that is about all.
by the looks of the rings there is a chance they are causing the issue , ive replaced rings in better condition that have caused issues, your symptoms and previous diagnostics's points to them.
cheers mitch

Thanks Mitch, just thought i'd ask the question since i have now taken the machine apart so if there was anything else i needed to do eg bottom seal then i' d do it now without having to dissassemble later.

If you wish to change bottom seal now is the time if its
soft and clean i wouldn't worry about it

Its soft and dry, there was some leakage between the crankcase and cylinder though.

sounds okay to me man , id leave it be

Noticed that on the bottom ring there is what I thing is called a ring expander, it's a corrugated foil-like object, does that stay or is it removed when I put on the new rings?

they normally dont fit with new rings and does no harm not being there , if the new rings dont come with them i normally don't worry about it