OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Fuel for Victa 2 Stroke

Hi guys,

I have a Victa 2-stroke Commando mower.

The NSW government will be banning the sale of unlead petrol from July and use only E10.

I have read from Forum E10 isn't good as a fuel. Are there alternatives? Is the Unlead 95 any good?

Anyone know?

The E10 is a bit unfriendly to the polymers in your fuel system, so they won't last as long. This is an issue to collectors and people (like me) who use old mowers. It isn't really an issue to people who buy Bunnings mowers and toss them after a few years, as long as they don't store fuel for long periods. Ethanol absorbs moisture and goes yellow: at that point it has a few extra undesirable effects.

The 95 octane petrol is a bit different chemically from the 91 octane stuff we use routinely, but that is a different kind of issue compared with the E10. Essentially, with the 95 you might find yourself having more gum formation in the fuel unless it is fresh.

To put a scale on the problem, imagine the worst outcome: E10 that was 95 octane. At that point you'd be in approximately the situation the US is in with its heavy use of octane improvers as well as ethanol in the fuel. You'd need to add a stabiliser if you left fuel in the tank for months at a time, and you'd have to expect fuel system problems (replace diaphragms, hoses, seals etc) a lot sooner than we are used to.

After plain unleaded is phased out my older cars will be running premium, and I may trial it in the mowers, ethanol blend fuel destroys the plastic fuel gauge caps in the old victas something severe, and I didnt just spend hundreds renewing my fuel system on my ute just to see if that will melt either...

Victa doesnt reccomend premium fuels used in 2 stroke mix either but what can ya do?

The old super was a premium fuel and there were no recommendations against its use.

Yes but today's premium fuel has detergents for the fuel system in it.

Old super was a premium fuel but not like 95 and 102 or whatever that other stuff is.

Super was super well 'super grade' because it had a higher octane rating than standard fuel which got phased out, not sure when im not that old.

Our unleaded 91 is a grade above anyway. Japanese unleaded fuel is 89 and as such japanese cars from way back have been built to run on this grade fuel. I think super was 93RON, i could be wrong.

It is common practise to jet up 2 stroke bikes to run on premium. I think the trouble with Victas is the fact that you can not alter the jetting.

I would be interested to know Victas official advice on whats going to happen in NSW with reguard to both old mowers and what they are going to do with selling new ones.

And politically i would like to ask WTF is wrong with you people?? Oh ok i didnt need to ask i know the answer, you get your cars and your planes and free lunches, congregate in your own little building, you dont have to live in the real world and do not care how things effect the average tax payer.

Leaded super was traditionally 98 Research Octane Number. That octane level became progressively harder to achieve as legislation gradually reduced the amount of Tetra Ethyl Lead that was allowed in fuel. In the end there was not very much difference between the "base stock" super before the lead was added, and 91 octane unleaded. The cars of the late days of the leaded fuel era tended to push the fuel pretty hard: Holden V8s in particular, were subject to burst detonation when launching from a standing start, and some trace detonation when they got a bit hot, on 98 RON leaded fuel. Trying to run one on unleaded 95 was a recipe for trouble, and not only because the octane was too low: they also relied on the lead to lubricate the valve seats. The unleaded V8 had induction hardened valve seats to control the problem.

Standard leaded was 89 Research Octane Number. Most Japanese cars of the period required 91 RON, so it was necessary to use super or shandy the two grades. (Some Japanese manufacturers had export models designed for the near-kerosene sold as fuel in South East Asia at the time.) The Japanese domestic fuel was always 91 RON as far as I know. If you've read about it being 89, I think you have read about it translated into American. The American practice is to rate the fuel on the average of the RON and the Motor Octane Number (determined in a variable compression ratio fuel-testing engine), and that is always lower than RON.

Part of the problem that arose when Australia switched to 98 leaded and 91 unleaded, was there was no place to get rid of the crummy base fuel stock that was previously used to make the 89 octane "standard" leaded. Fortunately by then very little 89 octane was being sold, since neither the Japanese nor the locally-made cars would run properly on it. Over the transition years, as the lead in leaded was reduced, and the 89 octane fuel went away, a considerably higher proportion of cracked hydrocarbons had to be used to produce the octane level required. That resulted in a lot of investment in the domestic refineries to increase cat cracking capacity, introduce hydro-forming, etc. The result was a reduction in the number of domestic oil refineries: the marginal ones had not done much if any cat cracking to begin with, and couldn't afford to start then.

i was told by a mower mechanic with the older victa's when mixing up the 5ltr petrol can use an additional 10% oil (220ml as appose to the standard 200mls, the extra oil helps with lubrication of the engine , is this realistic or a load of BS ? Thanks in advance

I seem to recall that way back when I first used mowers, the standard fuel/oil ratio was 16:1. Oil got better (2 stroke oil instead of engine oil) and engine manufacturers moved to 25:1. Some engines now are tested and approved by their manufacturers at 50:1, provided the oil is even better. These changes are arbitrary, dictated more by the environmental regulators and the marketing department than by the engineers. The regulators and marketers do not mind, within reason, if the life of the engines is shortened, and they would regard a 30 year old full crank Victa as a failure by the engineers who designed it: those engines denied them the opportunity to make more headway with environmental pollution reduction, and to sell more mowers.

So, how much oil is best? Well, how long should a mower engine last? Personally, I doubt that a 25:1 engine would last measurably longer at 22.7:1, unless there was a known design weakness in the engine that resulted in poor lubrication of some part of it. The extra oil will shorten the spark plug life, and make the exhaust smell even worse than usual.

Thanks for your reply Grumpy, so i have 2 stroke engines - Victa Mustang VC (1975/76) , do i just keep going with the 200mls:5ltrs fuel ? and use the premium fuel too Not e10 ? .

I always suggest that people do what the manufacturer recommends, unless there is some special circumstance. I don't see any special circumstance here with regard to the amount of oil in the fuel. (If you had a utility on permanent scrub-bashing duty on steep slopes with the governor removed and running flat as a biscuit, it might be slightly different, but only after you wore out a couple of engines and posted pictures of the worn out parts.)

So far as the fuel is concerned, I think there are advantages in 91 octane unleaded, with no ethanol. It is fairly friendly to your carburetor diaphragm and some other bits. If you can't get that any more, you have to decide between eating a few polymer components after a few years, compared with probably having more gum form in your carburetor than you are used to. Neither option is at all awful. Of the two, I think I'd rather have the gum than having to replace parts that will become increasingly scarce. Having said that, I should point out that because of the gum formation problem with all unleaded fuels, the major brands put an injector cleaning solvent into the fuel as standard equipment (they did that after some fairly heavy pressure from car manufacturers). The solvent is very chemically active: if you buy it as an "add this to your tank" substance, you have to take special precautions or it strips the tin plating off the inside of your fuel filler. The stuff is present in both 91 and 95 octane unleaded, but there is probably more of it in the 95, since there are more of the olefinic products of cracking, and they are the main culprits in gum formation. So, what effect does the injector cleaning additive have on fuel system polymers? I don't know, I was out of that part of the business before the results were in.

Perhaps i am missinformed, or didnt explain what i thought i knew, very well.
A lot of japanese carby cars were built to run on 89ron fuel. My pulsar and rodeo before it.
I thought that must have been the fuel they had there. I stand corrected.




On the victa oil ratio.
Applies to all 2 strokes running premix. Its a black art.

You have a container of fuel with oil in it.
You put some in the tank.
As the fuel goes into the engine it is metered by the jet in the carburettor. The oil in the fuel is part of this metered amount and is non combustable. (it does burn eventually but it is not the fuel that makes the big bangs) If you alter the ratio you are effecting the amount of fuel that is passing through the jet (because oil replaces it). So essentially you can alter the engines jetting by altering the premix ratio.

To burn off the oil the engine needs to be in good condition and running at a hot enough temprature. Poor compression and the engine will smoke. Engine running too rich (not enough oil) and it will smoke as the combustion temps are too low.
Engine running too lean (too much oil) and it could seize or melt a hole in the piston as the temps are too high.

I do not know how it works on a Victa etc. But on a motorbike the way to tell if the oil to fuel ratio is correct is too run the motor long and hard then pull it down and measure the depth of the pool of 2 stroke oil in the bottom of the crankcase. Hardly practical.

The rule of thumb is that the harder it revs the more oil that should be in the mix. 500cc single 50 or more to one. 125ccs 32:1. Ive owned quite a few 200cc two strokes and run all of them on 32:1 and never had an issue. But they have been jetted correctly to suit Vortex98 and the Shell Advance oil that i had and that was the only mix run in it.
The important thing is the correct jetting, the RON of the fuel, the type of oil and the ratio its mixed at are secondry factors.

New Yamaha YZ250 2t were still reccomended as 16 or 18 to one. That was 2 years ago.

Given that the Victa has a rev celing of under 4000rpm and most bikes will easy see over 6000 some as far as 10000rpm, you could say that the Victa is over oiled.
But if you drop the oil ratio the motor would be running rich.

It would be a great thing if you could get a series of sized jets for a victa. But for what it is and what it does it hardly seems practical.

In theory you could run a victa on 100:1 and it would do in no harm.
In practice im sure some Victas get run on 10:1 mix where the fuel has been left sit and the fuel has evapourated out.



Makes one wish for the days of the BP Zoom drum over again. Makes life pretty simple. Its surprising how many people are anti mixing fuel. Its not that hard, i dont see what the issue is.

Bob, in the pre-emissions days (prior to 1974 from memory) there were a few Japanese models sold here with the low compression export engines, so they could run on 89 RON. I don't recall any from 1974 onward.

I don't subscribe to your method for calculating oil to petrol ratios. I agree that changing the oil ratio will change the air fuel ratio a bit, but that is accidental. You put in the percentage of oil that the development team at the factory found necessary, then you size the jet to get the air fuel ratio you want. It is no trick at all to change the jet size: you just solder up the brass jet, and drill the size of hole you need. Jet drills come in size increments of 0.001". I've never felt prosperous enough to buy a full set, I've just bought a few in the immediate vicinity of where I expected to find the right answer (and usually lost them soon after the job was completed). You use a combination of clues to get it right: sound, maximum RPM, standing quarter mile time, and plug colour. Of course if you've modified the engine you get the plug colour right by changing the plug heat range, so you can't use that one as a clue for tuning the mixture. I did once use a different system for adjusting air fuel ratio, but it was just luck that method was available. My brother knew someone with a Non-Dispersive Infra Red oxygen analyser, and we used that. You can achieve about as much with an NDIR carbon monoxide analyser. The right equipment certainly makes a lot of jobs easier.

That's exactly what i asked. My interpretation from Grumpy's answer is that there will be shorten lifespan to the parts (such as gasket, seals etc) if E10 fuel is being used and fuel will form gum (turn solid?) if premium Unlead (95) is used.

There really isn't a black and white answer within the discussion. I guess it's a matter of trial and error.

I am happy to bet on premium for the sake of having better fuel.

I will ask Victa and see if they have answer and post back.

thanks for all the great info made for great reading right then i have taken a photo of the original sticker on the cowling cover of my 1975/76 Mustang VC .
My thing is this sticker was placed there when there was only "Super" 98 RON ...... the fuel situation in NSW is coming under alot of fire , be interesting how things go . Well those that run diesel motors wont really care much , well thats another topic in its self , so here is the photo

Humm quite an interesting thread and fuel I think is part of my problem
so informative yes

just for Gerson
from the FAQ of Vita Website
(wont put the link in just in case its a no no)

(Id be interested thought if you actually contacted them to know what they said..)

Quote
" Victa recommends the use of Regular Unleaded Fuel (RON 91) in Victa 2 stroke engines.
Fuel with Ethanol additive up to 10% may be used (Regular Unleaded with E10)"
Unquote

BUT they do not mention the down sides..So thanks Grumpy for that reply
and the rest of you all for your input too


pity BP zoom's no longer available
the beast use to love that stuff

both options are going to create more work one way or another
I guess...humm

cheers & thanks all

Thanks Deejay for the link!

I also got a reply from the technical services from Victa via email,

Quote:
Hi

95 has always been ok to use as well as e10 but e10 does not keep for long and at this stage we have no other information.

And there is no conversion kit

Regards

Briggs and Stratton

So i guess it's ok to use 95 after July.
Does Briggs and Stratton own Victa now? Must be old news i didn't know!

Anyway, thanks all who contributed! Greatly appreciated!!

I don't expect they would, the way Victa is going these days, they probably would like to keep the downsides quiet.

If it helps bring the 5 year lifespan of the new mowers down to 3, they'll take it!

Personally I will be switching to 95 when I can get regular 91, I refuse to use E10 in anything, especially my collection, as I have seen what it does and replacing vintage parts is not always easy.

I removed the "E10 fuel suitable" sticker from y car too, i plan to replace it with an equally official looking sticker reading 'E10 fuel not suitable' so that friends and family don't poison the car for me!

If your car is EFI E10 wont hurt it, as long as you do not leave the car sit for weeks on end.

humm yep Mr Davis
I never, well at lest thought I never used an ethanol fuel E10
but since I actually dont buy it, some else does I got a horrible suspicion at times beasty has been drinking it...and not liking it...id put nothing past some servo's either...I always ask then to get "no ethanol" regular)
(oh for some BP zoom)

That said, Welcome Gerson and thank you for their reply too

(might have to call me 59 not to be confused with the Original DJ on this forum..it is my nick true, but he was here first...
I should have thought of that when thinking of a screen name)

I did find a BP PDF on 2 stroke mixtures (25:1 50:1) and there recommendations
was 91( no ethanol) or 95

They did list a few things on the use ethanol as to why not
but said check with your manufacturer..just covering their behinds I guess

to Quote

"What about new BP Unleaded 91 with up to 10%
renewable ethanol?
While new BP Unleaded 91 with up to 10% renewable ethanol
is great for most cars, we don�t recommend it for use in
2-stroke engines without first consulting with your engine
manufacturer. This is because:......

plus a bit on well if you still intent to use..it blah blah

Anyway seems 95 might be the better option..
or possibly lesser of two evils I guess...

I might start another thread on this with regard to the beast as I have some questions but think that would be dragging this of track (topic)

Cheers all

& thank you