OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Twin: No Spark

The leads come out the same as if you are unscrewing a bolt.They screw in and out the same way.I really don't think your getting a accurate reading by making something to fit you will be making it harder for the current to flow.The reason the back sparks easier is cause it's closer to the coil.You have to remember with electricity current will flow easier via the quickest path and less resistance, which is via the rear,as it is closer to the coil.Fitting a wire which is possibly not a coil wire and adding a join will create more resistance.So try and unscrew the coil wires and use the leads,this also will show how good the leads are.There is no way the front cylinder can suck more than it needs to start.It is defiantly a firing problem not a fuel problem.The inlet is exactly the same set up as a 160cc engine.It doesn't require more fuel than a 160 in fact they use less,as there is two cylinders doing the job of one.Which in tern gives it more torque.Remember they are actually a 166cc engine not much more than a 160.So it defiantly sounds like an electrical problem to me.We just have to work out what exactly.

I can strip mine down and give you all the pics if you want



It starts great and runs awesome.
I dont know anything about it but i can send you pics of it.
i got lucky

Vccomm,

I Thought about the decompressors but I couldn't see that they could affect it and they were both taken from working machines so if all else fails I will change them again but I'm sure they are not the problem.

Blumbly; the "Extension lead" I made was just 2 in line spark testers linked up together. I checked and the spark was coming through nice and strong. I tried to unscrew the leads but they put up a good fight and I didn't want to force it. Come to think of it this may be my issue anyway. If the leads are rusted in this would be causing issues...I'll wait to find a working spare coil before I risk damaging this one further but you could be right regarding the path of least resistance.

I'm the same with cars - anything mechanical and I can work through it OK. Add electricity into the mix and it has my number VERY quickly!

Thanks,
Pete

OK SO UPDATE!!!

I picked up a parts twin today.

Changed the coil over and put it all back together. It started off doing the same thing BUT not running on the rear cylinder. kept persisting and now it is starting on first pull and running nice and smooth. It is now a good runner. Shut it down and restarted it a few times. Started on the first pull every time.

Seems like I had the first known coil with a faulty FRONT lead!

The machine I picked up today has a very good body but no wheels and the engine is seized solid. I'll be taking the engine off and using the body for my resto.

If anyone in SA needs any parts I have left (Metal cowling or busted and fragile plastic cowling, painted handles, seized engine, carby, body with crack on side let me know and you can have it free (IF YOU ARE GOING TO USE IT FOR TO GET YOUR MACHINE RUNNING FOR A COLLECTION AND NOT TO RESELL FOR PROFIT).

Thanks Blumbly and Vccomm for your help!

Well done and good on you. I have one and i randomly start it just to get a smile. its my ringtone, is that sad?

So I'd say it's more likely a faulty lead and not a faulty coil.That was why I trying to get you to changes the leads around.
on your victory I'm just glad I could help.
Good work.

I little sad yes but then I have the Simpsons song

Yeah, just did't want to force the lead off until I had a back up incase I broke it. I do tend to break things

Yes I know but you have to break an egg to be able to make an omelet.Some times things might have to be broken in order to repair them.
Again well done I'm sure you will enjoy it now.They are a totally awesome mower.

UPDATE on this one.

The parts mower I picked up is in overall better shape so I thought I would get this one running and pick the best engine to restore.

Cleaned up the flywheel and put it's original coil back on. No matter what I do I now cannot get spark from this one. FRUSTRATING!!! I know the coil, leads and spark plugs are fine so it must be the points BUT I have run into a problem I have never encountered before ... HOW do I get the flywheel off?

Usually I would just remove the spark plug and fill the bore with rope until it blocks stops the piston BUT no matter how much rope I put in both cylinders I cannot stop the piston moving. I checked and the pistons ARE moving through the cylinder so no problem there but everytime the get to near TDC and I feel tension when turning the flywheel by hand it just releases and starts moving again. I cannot get anywhere near enough tension to actually undo the nut. Am I missing something? Is there an obvious solution to this that I cannot see? Do I just need to feed more rope in?

Really hoping to get this engine going as the body is in much better condition and the bottom exhaust plate is not completely rusted out like the other one. If need be I'll just swap the engines over but I would rather not do that and keep the original body with the original engine (I know it's exactly the same and no records of what body goes with what engine but I'LL know and that's what matters).

Thanks for your help guys.

broken keyway ? might be why it was parked up before . try rattle it off and should loosen the flywheel too

I usually put a socket on the starter cup nut and one on the cutting disc nut. The starter cup nut should not (I repeat) should not be as tight as the cutting disc nut. It usually works for me. Failing that there should be a hole in the top side of the fly wheel between the fins,get a number 3 Phillips head screw driver. Line the hole up with one on the ignition plate stick the screw driver in that and undo nut. Not sure about the rope idea I've always found a better way. Give those two a try.

Hi Blumbly, I am posting this here because I don't know how to start a new topic - novice in these forum things, you know. Victa twin piston rings - size code 48 x 3/32 x.070" available from GS Burling P/L . ph 02 9452 5784 - Grahame. www.gsburling.com.au
I ordered a set this week 13/10/15. Please spread the word.

Thanks,
wombatini

Hi to all in this Victa Twin forum.

Whilst I am still a relative novice at these forums, I can tell you that the twin coils are weird creatures. In a normal single cylinder coil, one end of the HT winding is connected to the primary coil winding and BOTH are grounded to the chassis while the other end of the primary goes to the points. The other end of the HT winding goes to the spark plug and fires to earth via the plug gap.

The twin cylinder coils are relatively "stupid" in that they are a single HT winding BUT neither end is connected to the primary winding or earth and EITHER ends connect to the respective spark plugs, front and rear.

Now, to effectively test the output of these coils it is required that you ground the opposite HT lead to the side you are testing and if things are OK you should be able to throw a good blue spark for about 6 - 8mm. To test the opposite spark plug lead just ground the original HT lead and repeat the test for the other spar plug lead.

In theory, if you remove one plug lead and leave the other connected to a spark plug you should not get any spark at all ! Why? Because you effectively have an open circuit and no path to earth / chassis. In effect, the whole HT circuit in a Victa Twin coil is open circuit until the spark plugs are connected.

This is why BOTH THE SPARK PLUGS MUST BE IN EXCELLENT CONDITION AND POSE NO SUBSTANTIAL PATH TO GROUND THROUGH THEIR BODY / INSULATORS AS IF THEY DO, ONE CYLINDER WITH THE GOOD PLUG WILL GET AN EXCELLENT SPARK AND THE OTHER WILL GET BUGGER-ALL. Therefore if you change one plug for a new one it is very wise to do the other at the same time as they share what HT is available, relatively evenly, in an ideal situation. Small wonder that they cause so many problems, then. SO... the moral of this is - Always ground one of the HT lead when testing the spark AND renew the plugs as a set only.

Hope this clears up some questions for the Victa Twin fans, of which I am one. I have an original red 500T with the separate chassis mounted primer bulb and a later gold Supreme, a spare Supreme engine complete AND a spare coil. All run very well indeed.

Hello wombatini and Contributors

That's the best explanation of the workings of the Twin Coil I've read.
This should prove a valuable resource to members.

Thank you.
--------------------
Jack

Hi Jack,
Thank you very much for your comment re the "weird" set up with the Victa twin ignition system. Being a sparky / electric motor rewinder by trade helps. I wonder if you might be able to help with another matter that is stalling my progress in restoring a Victa Model 2 Rotomo. I have mechanically rebuilt the engine BUT the magneto coil is, for the want of a better word, BUGGERED ! It has the Wico - Pacy magneto, type FW ????? . I cannot read the Spec no. as it is too feint maybe FW 159? ? Can you, or any contributor with greater knowledge of such things tell me the type number and where I might source a new / used coil ? The condenser and points are like new. If I have to I will attempt to rewind the coil but that is a lot of work with no guarantee of success afterwards.
Cheers to all,
Wombatini.
PS I was watching a Utube video today whilst searching for these things when I came across a Maytag twin two stroke engine with a Wico magneto. Looks like the very same set up as the Victa twin, simultaneous firing two stroke. But the coils set up was exactly the same - single winding, two ended secondaries going to the plugs. Who copied who...................... maybe ?

Hello wombatini

I'm out of my magnetic field here, so I am hoping a member can chip in
and offer a solution. I don't recommend NOS coils because of the
deterioration of the copper windings over time.

I guess the magneto is this one:



New re-manufactured coils are available from the UK but are wico-pricey,
if you know what I mean...
http://www.villiersparts.co.uk/wip.html

Hope this helps.
-----------------------
Jack

Hi Wombatini,

thanks for your explanation of the twin plug setup. Thus my advice elsewhere was wrong regarding grounding one side. I had assumed the plugs were wired in parallel and I should have known, as you said, that once one side sparks resistance breaks down and prevents the other side sparking. I did think of it but somehow convinced myself otherwise! Series makes sense. And grounding is therefore not a good idea!

Actually I should have twigged as I went reading about magneto setups afterwards...it seems this system was used in the Citro�n 2CV. On such engines it is called a 'wasted spark' system because with a 4-stroke engine, the system fires on both the compression and exhaust stroke per-cylinder (no such issue with a 2-stroke of course, nor is the Citro�n 2CV a magneto system).
See Wikipedia Ignition systems-Mechanically timed ignition] and wasted spark systems. Once exception is where both plugs are in the same cylinder (twin-spark)...in which case the spark is not wasted as the coil will only fire the plugs on the correct stroke.

Old thread I know, but has this been resolved "officially"?
Are the two plugs in parallel, or (as would be better) in series?

If, as above, they are in parallel, then, yes, one shorted plug would sap all the spark energy from the other plug. THAT would mean if one plug was fouled then the other wouldn't get spark and they couldn't run one one cylinder.
But we all know they can, and do.

Hence I contend they are wired in series. One HT coil, completely isolated from the chassis (ground) and isolated from the primary winding.

When the primary current is interrupted by the pints opening, the inducted HT current goes to one spark, through the chassis to the other, then back to the other side of the coil secondary winding.

So both plugs fire together. If there is any short circuit from one plug to ground (wet plug, cracked insulator, dirt etc) the other plug will actually see more energy than if it was sharing the spark with the other plug.

In multi-cylinder engines (Commodore Ecotec V6 comes to mind) this is how I believe they run them. They are wasted spark with two cylinders sharing one coil. Hence they have three coils.

So if one plug fails (short circuit) then the other one of the pair still runs fine. You only lose that one cylinder.

Now there's a thought... I wonder if a Commodore V6 coil could be adapted, using a 12Volt SLA battery and the Victa Twin points?

Hi victatwin, been there done that some years ago on a 125 2 stroke Fling Flea motorbike that had Prince of Darkness ignition that barely worked from the day they left the factory during the war. Being a single cylinder I used a Holden coil and a small gel battery to power it and worked fine. You could use any twin outlet motorcycle coil as long as it came from a points ignition motor. CDI coils may work but I'm not sure.