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

Hi all,
A newbie here and below is my latest purchase from Ebay. I've always wanted a Utility mower as it suits my current yard better (Small areas with lots of slope and overhanging shrubs).


I acquired the mower yesterday and started mowing. At first we had smoke, then that cleared and mowing was going well until after 15 mins then it started to idle slower and then stop. After a couple of attempteed restarts where the mower would start up but not seem to get up to full revs before stopping again. Eventually it just wouldn't start. Emptied and cleaned out fuel tank. Went and purchased new fuel and dried carb out. This morning it fired up first pull ran for about 30 secs (again not up to full rev's) then stopped. I use the victa 2stroke oil and mixed at 50/1 instead of 25/1. I've done this for a number of years now with my last mower and had no prob's. I've always used old mowers and self serv'd. Any clues? I'll be removing muff tonight and checking for scoring on piston/rings also. As I write this it sounds like I've seized the motor but I don't think I have as I've done this in the past and this didn't sound like it was running dry. I want to get this puppy fully restored so I don't have to buy another mower. (old stuff over new any day). Also if anybody can tell me a bit more about the engine that would be appreciated also - or which manual I should be looking for.. (Or point me at a previous post).

Cheers FF

Id go back to the 25:1


Changing the mixture of oil changes the jetting as the oil takes up volume in the fuel.
Richer in this instance. Lower combustion temps. More smoke.

Sounds like a fuel blockage. Id check that first.

Or spark issue, check the earth is good where the module goes on the motor. Or that the points are OK.

Could be a heat related ignition problem too.

Thanks Rodeo. That gives me a few places to start. Easist is obviously fuel mix. By fuel blockage do you mean within the carb as the flow is good from the tank to the carb. I did check the plug and that it was giving a spark - can I sasume from that the points are OK. I'll clean the contact for the earth while I'm at it.

Fuel blockage in the jet or the needle and seat.



Check that the stop wires that earth the ignition that go into the carb are doing what they are meant too.


Is it a Mk 1 with points or a MkII with electronic ignition?

Thanks Rodeo - I cleaned the jet and needle and seat while carb was drying out. Stop wires are setup correctly. As to MkI v MkII, shat would I be looking for to tell the diff? I can see a coil? with wires attached underneath the top cover and facing the rear of the motor. Sorry for the obscure description.

The MkII with the electronic ignition will have a module (gold coloured box about half the size of a match box or smaller) riveted to the wing on the engine that the cowling attaches too, just above the carburettor.


Bob.

Thanks Bob,

It's the MkII. I have checked the piston and it is fine. Tonight I'll go through the steps outlined so far and see if I have any joy. Thanks for your help so far.

Fixed!!! Now starts beautifully 1st pull. To cut a long story short I stuck the plug (Non champion) in from my old mower and off she went.

If you want the long story :
Pulled covers off and recleaned float and needle in carb;
Cleaned earth contact;
Cleaned fuel tank, line and filter, added fresh petrol mixed at 25:1;
Checked back of carb to ensure cable pull was seated correct and doing its thing;
Put together and could not get started.
Read some forums a bit more and got worried about compression. Tried cap full of fuel down spark plug hole and no joy. More worried about compression...Removed plug, checked spark. Did basic compression test by trying to hold my finger over plug hole. Pulled cord many times to see that fuel would build up on my finger to ensure fuel line was working - it did.
Went to old mower to get plug and was about to pull cowling off to stick plug in decompression valve hole etc and also test without muffler, when I thought to my self before doing all of the above quickly test with different plug. It appeared to be a better spark with the blue colour I have read about mentioned here and what do you know... First pull. Don't even have to pull that hard actually. Very happy.

If anybody has read this far - I have a couple of other questions.
1. if you left plug connected but sitting near exit of plug hole and pulled cord a number of times would a little ignition happen or does it required the compressed space with in the cylinder;
2. I put some new blades on but when I got home I discovered they are 10mm short - turns out they are for a ute with a bar and not disk. Is this an issue?

Thanks Bob for bothering to help a bumbling office worker who likes to play home mech

Hi Freddy, nice mower you have there. Good pick up.

In answer to your questions, leaving the plug sitting near the hole won't cause any sort of ignition to cause concern. As long as the mechanical parts are good, the three things an engine needs to run is Fuel, Spark, and Compression. So the miniscule amount of uncompressed fuel that would be present won't do anything.

I can't see any issue with shorther blades as long as the blade disc is still balanced.

Cheers, Greg.

A point of clarification Freddy. Your spark plug can only spark if the body of the plug - the metal part with the thread - is grounded, say to the cylinder head or cylinder. Whenever you are in doubt about the ignition system, it is a good idea to check the spark directly from the end of the plug lead to the cylinder head. If you get a fairly strong spark that way - it had better be blue and at least 3 mm - then you have ignition but may well have a bad spark plug. Remember, 2 stroke spark plugs are poisoned by the oil in the fuel, and may have a weak and unreliable spark after about 15 hours' use. If they've done a lot more than 15 hours, even cleaning them is only partly and temporarily helpful. (The situation is quite different with 4 stroke spark plugs - I tend to use them until the electrodes are eroded enough to change the heat range - but I have to file the contact surfaces every few years, because they develop cracks and cause high resistance.) Also, it is by no means uncommon for new spark plugs to be defective. You should always check the ignition with a known good spark plug, and a new one is not known to be good.

I don't like to put the spark plug close to the open spark plug hole to check spark with 2 strokes. Unlike a 4 stroke, the 2 stroke will expell unburned fuel from the plug hole each revolution. With the spark plug sparking close by at the crucial moment, this can cause an accident that might (with a fair amount of bad luck) hurt someone or cause a grass fire.

I'm back

I've tried to use the mower twice now and it goes well for about 10 mins then just stops. Any clues?

Other symptoms are:
Doesn't appear to rev up to full speed;
Seems to be blowing a lot of smoke;
Struggles to cut medium length grass;
Starts well from a cold start.

What are the signs of a heat related ignition problem?

That gives symptoms to me of excessive ring wear, usually if a ignition module is failing once it warms up it just quits completely.

Thanks Joe,

So replace rings? Any way of confirming the ring wear before I go pulling it apart and forking out the $$.

If rings required is there anything else I should be replacing while I've got her apart?

I guess a new gasket and perhaps the large rubber O ring. Should I have local mower shop give her a hone out?

To check the condition of the rings before dismantling the mower, remove the decompressor and replace it with a spark plug, then pull the starter a few times with the ignition off to see how the compression feels. Then remove the spark plug, put a spoonful of engine oil in through the plug hole, replace the plug but don't connect the lead, and pull it over a few more times to see if the compression has increased. If it has increased substantially, gas is getting past the rings. That usually means the rings are shot, though it could also mean the bore is badly scored. However it would be unusual to wreck the bore that badly without also wrecking the rings.

If the compression is good with or without oil in the cylinder, and the oil makes virtually no difference, the problem is not the rings, or any other source of blow-by. If that turns out to be the case, tell us and we can look for other problem areas.

Thanks for the tips Grumpy. I'll go through this tomorrow and see what I can determine. Just to quickly clarify - when you say 'to feel' if compression has increased would that mean it will get harder to pull the start cord?

Yes Freddy, but it will get a lot harder to pull it anyway when you remove the decompressor. That is why you have to test it twice with the decompressor removed: once without oil, and once with. Remember a crankcase induction 2 stroke has compression twice per revolution. One is the crankcase compression the other is the cylinder compression. With the oil in the cylinder they should both be quite sharp resistance to pulling the cord. How much resistance there is without oil in there, is what we need to find out.

Just to elaborate a bit on what grumpy suggested, a tea spoon of 2 stroke oil rather than engine oil.



As far as the blades go, you got the ones for a later model, a power torque which has the oval shaped disc.
The full crank utilites had their own disc with a blade that was about half an inch longer than the rear catcher models.

You could try and find a 'turbo thrust' disc, i believe that this is the only one that will work on your mower with the blades you bought. Power torque disc will not swing past the handle mount bolts.


First try pulling the back off the carb and checking that when you move the throttle lever that the grey plastic thing in the carb is getting its full range of movement.

This might be part of the full revs and low power.


The module for the ignition could be no good as well. It could just have a bad earth, corrosion and what not over the years.

If you dont have spares im not sure how you would check this. A new ignition module is nearly $30.


If you are sure the carb is right then check the compression. This wont be much to do with low revs, mostly its opposite but could be a big part of low power and definately will contribute to the smoke.




As far as new rings goes.
The gaskets come in a set, head base and exhaust and its about $10. Or you can get just the head and base. Rings are not expensive. Not hard to do. Even if it were only half worn its worth doing for peace of mind. Plus you can clean out the exhaust port while you are there, its bound to have a bit of a build up of carbon in there.

Hi all,

Have finally got a chance to test the compression as Grumpy suggested. There was a noticeable difference before adding oil - felt like I hadn't removed the compression valve. Post 2 stroke oil (Thanks Bob) I could hardly turn it over. So it's off to the mower shop now for engine rebuild!!! Rings not a hard job in the scheme of things.

Bob - I've had the carb apart and I'm happy there is no problem there. Also timing appears to work fine based on the spark coming out of the plug in time with rotations of the flywheel.
I'll post a report post ring change.

Just a quick note, Changing the rings on these particular engines is a pretty simple job for the home, and much more cost effective to do yourself.

Take off the cowls, then the 4 head bolts, pull of the head, then slide off the cylinder.

Remove the piston (careful not to bend anything) and inspect it, then swap the rings over carefully (you can use an old ring, filed to a point to clean the grooves) refit the piston, whack on a new cylinder gasket (after removing all the old one) and compress the rings as you slide on the cylinder.

Slap in a new head gasket, refit head, bolts, cowl, and you are done.

With the timing, I'm having trouble understanding what you are using to reference the timing, the spark needs to be 3mm before TDC (top dead centre)

I would definately suggest that you do the rings yourself. Its a very easy job and the 70+ you would pay in labour for the job will buy a lot of beer.



Even if it was a power torque i would suggest doing it yourself, its not hard to make the special socket to remove the big end pin.