OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Plug Fouling Victa

Hi, I have Victa PowerTorque-160 that has nasty habit of fouling plugs on a weekly basis. I have tried different plug brands, precise fuel mixing, new decompression valve, head gasket, checked the exhaust but yet no luck. This mower starts first pop (with fresh plug of course), runs great with heaps of grunt and is probably my favourite mower out of six sitting in my shed, just a shame about the plug issue though. Are PowerTorques hard on plugs in general? Cheers

Mr Jims,

Need more information than what you have supplied.

1. What two stroke oil are you using?

2. Have you changed the air filter?

3. Did you put the air filter in correctly (hole down).

4. How old is the machine and how much work does it do?

The plugs don't normally fowl up.

Give us these answers and we will go further.

Hi Bruce,

I use Stihl or Castrol Super 2-stroke at 25:1 ratio (40ml to a litre of 91 unleaded)

Air filter is clean and installed correctly.

I bought it second hand, have no idea of age but quite a few years old for sure. Removed head, the honing pattern inside cylinder is definitely not factory, looks like it's been done-up at some stage. Compression is good though. No way you could pull start it with the decompression valve removed and plugged.

I use it daily as a back-up mower for my mowing round.

I'm guessing rings. Plugs seem to have some carbon on it. What about air fuel ratio? Although filter is clean, it does smell rich.

Cheers

Does the muffler feel heavy because they have a gauze inside and the carbon blocks them up.

Also the ring gap should only be less than 17thow if larger then you will have to replace the rings.

The ratio is correct 25:1

Hi,
I would change the oil mix to 25ml of oil to 1Lt of unleaded.
I'm probably going to get some arguments here but 25:1 ratio is to strong, it causes plugs to foul up, exhaust ports to carbon up, mufflers to block, blow blue smoke all the time, makes it hard to start from cold because of oil sitting in the carby, and reduces power.
I've run 25ml to 1Lt for 18 years in all mt 2 stroke equipment and never had one seize up yet.
To much oil can also give to much compression as well, can't pull it over without the decompressor.
Well thats my opinon.

Hi mr jims, i was thinking about this and wondering if your sparkplug is right one for mower or plug is too cold as they say,perhaps worth a try, dont go too hot though as could damage engine..besides that all suggestions so far i recond is worth looking into.reducing oil a little and looking or changing muffler definatly a goer.. next obvious thing would be to check ring specs, or even oil ring could be stuffed ...Toroman

Just a quick question? Is the plug really black and carbon fouled or is is it getting a fine hair of carbon across the gap?I doubt it would be rings cause I regularly see these mowers with really low compression before they start playing up.Your fuel mix is right but what plug are you using?Older powertorques used cj8 latter ones use cj8y.Make sure you use the thing flat out thats why victa put stop start and run only on the throttle control cause two stroke are not very efficient at low rpm.only things that cause running rich that have not been discussed are main jet (victa have used different ones over the years they are denoted by circles on the front of the jet) most common jet has flat face with just screw driver slot.I have come across jets that have been drilled to stop machines over reving.Air leaks at manifold and starter sometimes cause fine hairs of carbon across plug.Also take the starter off and see if the crankcase is full of carbon.If it is its usually air leak at the starter