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

Hi all,

I'm having a senior moment here I think. I have just begun working on a victa twin (500). It is in generally rough condition and if it was any other machine I would part it out and scrap the alloy base BUT i think I'll keep this one alive for a bit longer.

I have cleaned out the carby so as soon as I get spark it will be ready to go (Hopefully).

Thus far I have cleaned up the coil and flywheel magnets, changed the plugs and isolated the kill switch but I cannot get spark. I am trying to avoid taking the flywheel off at the moment as I cannot find my puller. Can someone please post a photo of the coil (So that I can see if I have my wires in the right positions etc) as when I picked it up the previous owner had unplugged everything and had it all in a bucket (Obviously he couldn't get it going).

I don't want to try removing the flywheel without a puller because I don't like my chances of finding a replacement WHEN I inevitably smash it into a million pieces.

Forgot to mention: When I first put it together I did get a very weak spark from the front plug but it died soon after.

Going on how much rust there was on the magnets and the general condition of the machine I would suggest the points probably need a good clean up BUT like I said, no puller right now and I can be rather heavy handed and impatient.

Thanks,
Pete

Shouldn't need a puller to pull the flywheel off with the Twins.I never have should just wriggle off.Depending on which model motor you have it may not have point as I believe I think it was the 3rd updated engine had electronic ignition.
As for the picture you asked for here is the coil set up.
Not real hard,1 wire runs to the earth.
The other two that come off the same connection,1 runs to the points and the other to the carby kill switch wire.

Here's what the points look like.This engine is the first of the Twin engines and isn't one of the updated versions.So it didn't have the dust cap to cover the points.The updated engines did.That's why you can't see the rubber o-ring on the ignition plate.

Hope they are of some help to you.

Great thanks. I had it right - I actually just found out that my spark tester bulb was blown and that I did infact have spark. It is now very strong after I cleaned up the coil and flywheel BUT it still wont start.

I now has no compression at all in either cylinder so I have a bigger problem now ... While turning the flywheel by hand with the cowling off I can hear a quite audible whoosh sound so it has a leak from somewhere but I am not sure where. Tomorrow I will pour talcum powder over the engine and see where it blows from but all I can think of is someone has removed both head gaskets and not replaced them. The needle doesn't move at all on the compression tester (Yes, I know the tester works this time).

Anyone have any other suggestions? This is the first twin I have worked and am not very familiar with them.

Thanks,
Pete.

Wait up, Sorry to waste everyone's time. I did a stupid thing (It's been a long day). I didn't remove the decompressor valves ... I'll look at this again tomorrow.

Don't mind me - acting without thinking first ... Watch this space!

Thanks,
Pete

They don't heads or head gaskets for that matter.It is all just one casting of alloy with a steel sleeve for the bore.
See below.

Hopefully it will be a decompressor valve or both,as other than that the rings could be be shot.It also is a common problem with them.If that's the case sorry you just won't find any spare parts for them as there is none.
Good luck I hope it's not bad.

Why are you removing the decompressor values?

hmmm. that's interesting. I didn't notice they were just one full sleeve.

I figured if I remove the valve and replace with a spark plug it will give me a better indication of the severity of the problem - if I still get no compression the problem grows. If I do then I can swap the valves over with known good ones.

Here's hoping!

Thanks for the photos!

Pete.

Just don't forget that at low speeds two strokes don't have a lot of compression,and by taking the decompression valves out and putting in spark plugs,will add to the compression which in turn allows the engine to rev harder which is not a good thing as it will over rev.
Just be careful,maybe put the spark plugs in and turn by hand that will certainly let you know.I just wouldn't recommend starting it with them in.I know people have do it for years and a lot of those engines I've seen fail,I believe due to that.

Hey Blumbly,

Don't worry - I wouldn't run it with the spark plugs in place. Just to test and then I would fit new (Or rebuilt) decompression valves. I don't believe in make do repairs - If it's worth doing it's worth doing right.

I know people do very stupid things in the view of a quick result but I would love the idea of my machines being handed into a museum in the years to come not a scrap metal pile.

Thanks for your help. I'll report back when I have more news.

Pete.

Awesome I'll look forward to hearing how you go.

So spend a bit of time (Having had a good night's sleep so with a clear head) working on the twin today.

Happy to report that I found the problem - both decompression valves were stuck solid open. These have now been replaced and I have 40 psi compression.

5 pulls and away it went.

It did die after 3 seconds and backfire quite badly though. I will have to wait until I can get a new diaphragm cap as I snapped the inlet off when removing the breather hose. I also want to replace the diaphragm itself as it is less than perfect and the ignition/kill wires as they. Once I do all this I will try start it again and see what happens. Once I fix all the issues I KNOW about I can find what else is going on with it.

Thanks for your assistance Blumbly.

Pete

Not a problem I'm glad you had a win.Good work.

Hi Blumbly,

Some progress on this one. I replaced the diaphragm cap and the diaphragm itself and got it running today. It was still backfiring every 30 seconds or so. Thought I might try to mow the lawn with it. Got 1 metre and it died. Since then I cannot get it to start again. I have lost spark again.

I'm thinking the coil was the reason for the backfiring and now it has possibly gone the way of the dodo. Just wish I had another coil to test it with now.

OR do you think I may have another problem? I used a new spark plug tester and also tried the plug against the body of the mower to test for spark and nothing

Thanks,
Pete

seems you lost spark yes , sure you cleaned it allup when it was apart ? if it backfired (think of cars now here ) if it ran and was ok , sputtered then nothing , damp / wet / dirty ?? or maybe it did die ... still not up on twins and wish i was ! , this one i take it has points ?

Did you check that the cut out wires in the carby aren't shorting out.As when the rubber boot wears the wires can touch causing the very same problem as you have.As for back firing it could still be the decompressor valves as usually it is compressed air escaping through them.
They were know for coil problems but you usually loose spark for the back and the front usually has some sort of spark.I'm not sold that it is a coil issue.
Did you check the points?
vccomm not all twins had points some did have electronic ignition.

its why i asked matey

...and that is how we learn.

may I interject perchance?
My victa twin wont rev hard for more than 10 seconds will idle all day. clean fuel and tank. poppet valve setting??. sorry to interupt this post

havent checked the points as yet (Ran out of time today). The decompressors I have installed both came from running machines and I completely isolated the kill wires to check for spark. I'll pull it all off again tomorrow. It didn't get wet while I was playing with it so this onw has me stumped. If I had a 2nd machine I would change the coil over to test it but alas I do not.

I'll have another play around, clean it all up and check the points and report back. With all this reporting back it kinda feels like I'm on parole!

Thanks for the pointers.
Pete

Hi Seanw, your symptoms are consistent with a blocked jet. Spray with carby cleaner and poke through the main hole with a piece of bread tie wire or a strand from a wire brush, spray again and blow with compressed air. It should see it right. While you're there remove the primer face and clean float chamber and primer face too. Be prepared to replace the main o-ring as after its disturbed from sitting there for such a long time it will most ptobably leak on re-assembly.
Let us know how it works out for you.