OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines G4 & LM - Newb Questions

Hi ,I just posted on the introduction forum.
I have 2 Victa 2 strokes,I don't know much about them except they SEEM have the same carb, but I cant tell a LM from G4 How do you go about identifying years ,models and engine cc etc?

One has V40 Silver Streak and power torque stickers and the other has VL400. They appear similar but the V40 has slightly bigger front wheels and only has 2 cutting blades,the VL400 has 4 blades.
The V40 has a damaged thread in the carb that the main jet screws into allowing it to leak fuel constantly. After looking around at youtube videos I suspect it also has an air leak somewhere because when it does run ,it does so at high rpm then stalls when you try to turn the rpm down.
I'm swapping the VL400 carb onto the V40 today. I have mostly new parts and 2 carbs and I'm hoping to get one good one out of them.
I will be checking the seal between the manifold and engine before anything else
rosco

Ill post some pics later

I swapped the carbs ,checked the seal around the manifold and it looked ok. It wouldn't start so I used starter fluid which got it going. It seemed to idle too high and wouldn't shut down via the throttle control, so I had to switch the fuel off.
Ill have to check the wiring, I'm sure I had it right, maybe it come loose when I was fitting the carb.

The silver streak has 3/27/87 near where the carb connects. Is that the date of manufacture?
The VL400 does not have a date in the same place.

You have 2 of the toughest mowers ever built, designed by Australians for Australian conditions, bases rust out in the top left hand corner but the motors go on forever

Yes, I watched some videos that mentioned rust. Most of it seems from owners not cleaning underneath. Both of mine are quite clean and rust free. The engine on the Silver Streak runs strong when it runs.
I had the pull start off. Seal seemed ok .Bearings on con rod didn't have any slop in them.

I have never owned a mower before and its been 40 years since I even owned something 2 stroke.

I give them a good clean out in the rear area with a wire brush and then paint them with fish oil

Norm, for a moment, I thought you were talking about politicians there ...

That's good advice - on preserving the base.
These appear to have been designed with a limited life span.
Stress corrosion seems to have been built into the design.

--------------------
Jack

Hi mate,

If you've had the starter off I strongly recommend replacing the o ring. There are 2 o rings on the manifold too. A small one and a slightly larger one. These ones wear out less frequently BUT it's worth checking. Also the spring washer on the manifold could be worn out. May be worth checking that out later if nothing else works.

Biggest question though is do you have spark? If not try disconnecting the kill wires and see what happens.

If the rubber boot on the kill pin is worn it MUST be replaced. When the rubber boot is work either kill switch will not work and you will ALWAYS have spark OR you will NEVER have spark.

Test out your decomp valve (attach clean fuel line and suck on it. If it closes then it's OK). After that think about the head gasket. If that doesn't fix it keep it for parts and get another one. These engines are fantastic but a dime a dozen so don't waste too much time and money getting one to work.

90% of the time I find it's either a leaky primer cap O ring, leaky starter o ring or incorrectly fitted/damaged kill wires.

Good luck.
Pete.

Hi Jack, it would take more than fish oil to fix a politician

Thanks Pete ,plenty of spark. I'm getting a lot of leakage around the primer. I don't know why because I have used a new primerplate,o ring, float and float pin(I forget the proper name). I have also changed carbs. I said earlier it was a G4 but now I think they are LM.
The O rings on the starter and manifold looked ok but I will change them as soon as I can get new parts. The spring washer seemed to be ok
At the moment its the fuel leak that has me baffled.

I have new rubber boots on the wires

I think I also have dry spark plug, meaning its not getting fuel into the combustion chamber, so insufficient vacuum me thinks.
Rosco

zimtuff, the G4 had the adjustable idle screw cap, the LM didn't, I can't find anything different between them apart from a black poppet and cam, but hard to tell with the cam, Victa seemed to be trying all sorts of cam profiles to try and get them to work. Problem is as you say the plug is dry, this is because the float needle, even if it is new and the primer cap is new, the needle either sticks up in the seat, or it won't shut the fuel off, rubbish design, and poor quality replacement parts. Where is the fuel leaking from, if it is coming out the breather hole in the primer bulb, means the needle isn't sealing. The fact the plug isn't wet, I would say the needle is sticking up. A light sanding of the 3 ribs on the sides of the needle sometimes helps to make it drop. with the cap off if you put the needle in and the float on you can hold it up and by raising and lowering the float the needle should follow it up and down

Fuel appears to be leaking from around the base of the primer cap. The needle is new but as soon as I saw it I thought it pretty crappy. I will try sanding it down.
The needle seems to be getting stuck, you have to tap it with your finger to make it drop down. I should have kept the old one
Which way does the needle go in? The one I have seems to have a similar end at each end.

I cant see an idle screw anywhere and the poppet on both carbs is white.

zimtuff, sorry I can't give you much advice on the problem with the primer cap, they are one of the worst designs I have ever seen, I spend countless hours trying to get one to work, swapping heaps of needles and caps around and sometimes I can get them to work and sometimes I don't. This happens with new caps and needles, they really are rubbish. You have to put the needle up to the light, one end has a pretty dodgey looking sort of point, which is not central and I think this could be part of the cause of the needle sticking. I'm sorry I do not have a fix for this crappy design

I had some success. I found a mower shop that stocked OEM parts. I bought a new oring(the other new one had a chunk of rubber hanging off one side) and a new needle.
The new needle can only go in one way and it slips and slides like it should.

I put the new parts on with the new primer aftermarket cap ,and fuel was still gushing out.
I got out the old primer cap off VL400(The green one) and fitted the new seal ,needle. No fuel leak and it started 4th time after a couple of stumbles.

Next problem is it wont shut down, so inspecting the wires and rubber boots is next

I would also like to get it to idle a lot lower. What position should the poppet valve be in? Do the copper washers on the cam make any difference to idle?

I was looking at the "new" primer cap ,it appears to have a slight warp. There is no way the jet in the middle is going to seal the edges of the cap.

You got it, the new parts are junk, that is why you buy a pack of 5 needles in the faint hope you might get one to work. I haven't had any problems with new primer caps sealing, just can't get the needles to work. Great mowers let down with shoddy replacement parts. I can get them to idle and have full throttle control, (just finished doing one for Tiger) but there is quite a bit of modifying bits and it is a bit lengthy to explain. Getting the kill switch to work is an art form and the design was not one of Victas famous moments

I've also had a couple of Bynorm/GA primer caps that seem to be either warped or that the O ring land is too small. They leak even with a new O ring. Not to mention the needles!!

It probably isn't justifiable for a lawn mower, but a Mikuni or Tillotson carby conversion should make a difference.

I have heard that the older Victa G3 carby is well suited for kart applications etc.

It would be interesting to find out what sort of carby Ron Wheeler used on the Skycraft Scout that used modified Victa 160cc engines. https://en.wikipedia.org/wiki/Skycraft_Scout

The LM carby is a good carby, just let down by Victa trying to be overly clever and now let down by crappy needles,poor quality primer caps, and the bo bo kill switch abomination, apart from that a brilliant carby

I started it again today and it fired up 2nd try from a cold start.

I checked both of them for rust,VL400 had some minor surface rust and Silver Streak was like new.
Probably the Perth weather saves them. I was trying to mow the back lawn yesterday and I ended up with a mini dust storm.

I took the muffler off VL400, it looks like it has been running rich for a long time. The exhaust port is 40% blocked with carbon. The piston also had some lines in them. I'm not sure if its scoring, it didn't look too bad. Piston rings are intact and floating as they should.
Someone's had the head off before and it put it back on with no gasket.
I think this one is from the Adelaide factory because of the cooling fin size on the barrels.
This one might run with a cable and fuel tank.

Here is a link to repairing these carbs
https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/82291.html#Post82291