OutdoorKing Repair Forum Forums Repairs and Maintenance Questions On Ride On Mowers Questions On Victa Ride On Mower Frames Victa 4012GXT

Ha!! I didn't even think of looking on Ebay for one.

I dropped the bowl again and found the usual problem. Someone took it off and lost the gasket for the bolt. I reassembled it and now it's not getting any fuel. Guess I'll have to remove the carb and give it a cleanout.

Engine runs but still seems to be flooding. Governor keeps opening and closing. I can't see anything obiously wrong with the needle and float. Is there a place to measure with the bowl off to see if the float level is too high?

I don't know what has convinced you it is flooding. If it is hunting (surging up and down in speed by cycling the governor between its stops), that behavior means lean mixture. If it were rich it would slow down and emit black exhaust smoke with a characteristic smell of singed petrol. Engine speed might still vary, but not by slamming the governor between fully open and fully closed throttle. Instead it would be what is called 'rolling', varying in speed smoothly like a car with the hand-choke pulled out too far. Petrol running out the carburetor only means flooding if it is running over the top of the float bowl out of the overflow vent, or running out of the main jet into the venturi. A leak from the bottom of the float bowl only means a leaky float bowl.

it puffs a bit of black smoke when it surges and I can see it is spitting fuel out of the carby as I have the air cleaner off. I didn't run it very long so the new spark plug isn't readable yet but it was a bit wet when I checked it.

Paul_S,

Did this ride on mower come from a farm?

It's possibly from a farm but I don't know for sure.

I ran it again and this time it wasn't puffing black smoke but it's still spraying some fuel out of the carby inlet. I tried the mixture screw but it didn't make much difference. It might be lean as it backfired and stopped.

Paul_S,

Can you try running it without the muffler and see what happens?

OK. Will try it tomorrow.

What you called a backfire sounds like what the trade calls a spit. Essentially it blows back through the inlet manifold which results in a blast of petrol-air mixture puffing out of the carburetor inlet. It is often on fire as it puffs out. This is the main reason it is unsafe to do carburetor tuning experiments with the air cleaner removed.

Have you checked the ignition timing? Does the engine have normal compression? Spits can be caused by extremely lean mixture but they can also be caused by grossly incorrect ignition or camshaft timing. If you have a sheared flywheel key or a camshaft drive failure, much of this could be explained.

grumpy,

It could also be damaged valve seats or valves. In the past I have seen valve seats come loose which can cause the problem and if the valves are pitted will cause a bad seal as well.

I agree Bruce, any major leak from the cylinder into the intake manifold could do it. Anything involving valves, seats or camshaft is likely to show up if he checks the compression. The B&S 'Easy Spin' feature makes this a bit more difficult to investigate, but only a bit.

So far I have removed the muffler and run it with no noticable difference. It turns out the muffler is brand new and still clean inside. The blue flame from the exhaust was pretty. The fuel tap was fitted backwards but was still allowing some fuel to flow through at a reduced rate. I noticed some rubbish had shown up in the float bowl after the run so I'm soaking the carb at the moment. It doesn't have a fuel filter which can't be good. I haven't done a proper compression test but it feels really good when turning it over by hand. Doesn't seem to be leaky.

I put it all back together and it has improved a bit. It's still not right though. The higher the revs the less surging although there is an uneven valve pop especially at the higher revs.

Roughly how far out from bottomed should the idle mixture screw be as a starting point? 1 1/2 turns?

I leave it to you to do the obvious things like get the free fuel flow out of the tank up to the correct rate and make sure the needle and seat is clear and not sticking. You can waste a lot of time if you ignore the routine stuff. My B&S repair manual does not refer to your engine specifically. It may have the same carburetor as the 253400 engines, which is a cross-over flow jet with integral fuel pump. The idle and high speed mixture needles stick up vertically from right above the venturi, the high speed one being directly above the center of the float bowl. The correct first guess adjustment for the idle mixture screw on that carburetor is one turn, compared with 1.5 turns for the high speed mixture screw. Make final idle mixture control at 1750 RPM by setting the screw halfway between too rich and too lean. The correct float level is checked by taking off the carburetor, removing the float bowl, turning the carburetor upside down, and observing whether the float sits exactly parallel to the bowl mounting surface. If it's not, don't try to fix it by just pushing on the float. Use some science - carefully bend the float tang with long-nose pliers.

Can I really bend the float tang of a plastic float? Sounds risky.

My carb is different from yours. It's a Walbro with only one mixture screw sticking out of the side.

The float is sitting higher than your description. I checked the plug and it was running long enough to start to show colour. It's going dark brown on the electrode tip so it doesn't seem to be too lean now.

Whoa, do not apply any flo-jet lore to a Walbro carburetor. Flo-jets have brass floats, and many other differences. I have no information on new-fangled carburetors.

Do you have a fuel pump or gravity feed?

Some engine problems come from dirt and lack of use, and go away after running for a while.

it's just gravity feed and it's flowing well now that the fuel tap is around the right way.

If the carburetor is now clean, including the fuel hose and the needle & seat, there is no more crud in the bottom of the fuel tank, and the engine runs better and better as you run it more, the possibility exists that the original problem is going away. Might have been dirt in the fuel system. Might have been corrosion on the inlet valve or its seat if it's been ridden hard and put up wet. Personally I'd check the ignition timing, and the condition of the points as well if it has any, because you know this engine has been abused by an amateur.

Bruce, you said you have a workshop manual for this mower. Could you please upload any sections relevant to the work I'm doing at the moment? For instance...Walbro carb details and ignition timing stuff. Does this engine have points?


"because you know this engine has been abused by an amateur"

Hey! I resemble that remark.

I will try to upload within the next couple of days.