OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines monaro backfirng thru muffler

HI

I put a new muffler on my monaro and in the process I believe I may have disconnected a wire leading from the carb. So I put in onto an earth and now she backfires and blows smoke. So didnt want to do any damage havent tried to start her before I find out where the wire is supposed to connect to..

This is the mower in question

If that is a black plastic Victa 2 stroke carburetor, it should have two wires going into it. The only purpose of those two wires is to stop the engine when they touch each other inside the carburetor, when the speed control is put into the stop position. If you have permanently connected one of them to ground, either it is the one that is permanently connected to ground anyway, so it doesn't matter, or it is the one that only connects to ground in the stop position, in which case you shouldn't have any ignition at all, not even enough for pops and smoke.

I suggest you disconnect the wire from ground where you have grounded it, and try to start the mower. If it starts and runs properly, turn off the fuel to stop it, and talk to the plastic carburetor guys here about how to reinsert it into the carburetor successfully.

thanks - Here are some more pics, you can see the loose wire with terminal on end of it - must be simple - for some :-)

That is a ground lug on the end of the black wire, not the round terminal that gets pushed into the carburetor. It sounds as if there may be a partial short circuit inside the carburetor between the two wires that should only touch when the speed control is in the stop position. The previous tenant may have disconnected the ground lug to enable the mower to run.

Does it run with that ground lug not grounded? If it does, that matches my guessed diagnosis on the previous paragraph. It means that one of the two wires pushed into the carburetor is out of position inside the carburetor.

That wire is meant to be grounded under the front cover bolt.


As for the smoke, if the muffler was new it will smoke when its burning off the paint.

Couldnt say on the backfiring, could be anything.
Spark plug, rings worn out, points