OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines The sick victa thoughts please

The outboard oil thing.

Theres oil for water cooled.
And oil for air cooled.


For motorbikes it does not seem to matter too much which cooling its more a specified motorbike oil.

But for water cooled outboards the oil is a different formulation. I would say to do with the cooler cylinder temps and the fact that the burnt oil is exhausted through the water.



The bit i find difficult to get my head around with the Victa reccomended 50:1 oil is the jetting effect.
Oil takes up volume in the fuel. The fuel is metered. The oil is not the volatile combustable. If you have less oil in the mix you have more fuel flowing through the jet. If you have more oil you have less fuel.
Rich is cool. Lean is hot.
To burn the oil off you need optimum temperature and burn etc or you get smoke.

So i find it hard to accept that through oil formulation alone you can get an oil to lubricate the internals and burn off without smoking in an engine that is running cooler.

Its naught to do with the pre mix ratio, its everything to do with the jetting.
A low stress 160cc two stroke that spins at less than 4000rpm could easily be run on 100:1 mix with no ill effects caused by lack of lubrication.

Folk law has it that with a 125cc dirt bike its safe if you dont go less than 32:1 and they will wail well over 10000rpm.

Pleas read this post with a Noob alert light flashing
it more my thoughts and probably not technically correct..
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well I cant add much on the outboard thing

"L" plates here as you know

But yeah actually Bob thats probably what was bugging me, apart from panic
I read an explanation of why.. if you use a 25:1 ratio in a trimmer designed for 50:1 it will seize

Actually I saved it
but it was talking precisely
(now I remember) on what you mentioned "metering" & jetting
and I guess with the victa this isn't adjustable at all
as it stands (unlike other Carby's which have small range of play)


makes sense to me Bob, case in point being the trimmer


so actually its kinda a triangle of trade offs?

Air fuel oil...

so we actually have 2 ratio things happening..like a seesaw

So now correct me if I go this wrong

At a 25:1 mixture the engine will run hotter
Due to more oil displacing fuel
Air remains the same

result is a is a leaner mixture of air fuel

the reverse is the engine runs cooler

@ 50:1 less oil more fuel air remains the same
richer fuel air mixture ?

(since the engine was designed for a 25:1 its safe in this instant
which was my concern at doubling up the oil it will just run hotter which it should be capable of handling anyway)

now

I dont know when this formula hit the market
I've been using it( at 50:1) since about the time Zoom disappeared

Anyway
The spark plugs used now are BPMR4A from 2004 on I think
(I think that info was originally posted on the Victa site)

From what I gather this plug will result in a hotter burn then the old CJ8 (I alway used that but it was fitted with a RCJ8Y originally which put it about 98 vintage)

remembering my "L" plates here Bob so please bare with me

I dont know if this matters or even factors in really at all

but seems this will result in less fouling of the plug
cause of the hotter burning plug... BPMR4A
(I cant find my reference to were I read that)

so at a 50:1 with hotter burning plug what are your thoughts..?

to be honest I am not quite sure what that means, I am assuming it means more fuel burnt due to a longer burning time
but well I could well be barking up the wrong tree on this

anyway just thought I mention it
as "if" it does factor into the equation
its probably over looked
(maybe this is way there seems to be a few plug changes over the 98~2004 period...apart for Eco friendly but again pure guess work mate)

Oh and Bob It was in the post I lost...
but we did get another new mower fitted with a VEX60...
I was barred from buying a second hand one

still I fully intend to fix this one as its little smaller and more useful in tight places here

plus how better to learn

Cheers & thanks

(I still like the idea of a victa farm)

I have no idea where the 50:1 came from.

I have not see the owners manual etc that you would get with a newer Victa so i am not at liberty to comment on what advice they give.


What i could surmise would be that Victa were offered money by Valvoline to approve this oil, and needing money they took it.
But then perhaps the research was done, but given that it craps in the face of theory i am not convinced.


I got what i believe is a 2002 model mustang the other day. The 5HP motor with the straight inlet. The cap still has 25:1 embossed into it. The sticker on the side of the cowl that says about the fuel tap and primer still has 25:1 on it.
Untill i see a Victa with 50:1 all over it, the ratio i will use and reccomend is 25:1


I do use that same oil in my chainsaw. It was all bunnings had with that handy measuring cup built in.


The spark plugs in the later ones are a resistor plug. I do recall reading somewhere that it is something to do with the ignition, but generally a resistor plug is to reduce the electrical interference that the mower creates.
The number is the heat range and that is the same BM4A-BMPR4A CJ8-RCJ8Y The letter reffer to architecture.

Seems victa are still saying use at 50:1 in the 2 stroke manual for the oil above V2
I guess to me it was a case of "whats so special about this oil?"

seems some form of "U beaut" synthetic or semi might be part of the key on that... why they'd claim that I suppose
(no info on the bottle)

Sadly I can't say for certain that this mower hasn't had raw petrol through it
(and its very possible it has)

All I can say is that the last 6 years or so I have run it at 50:1 with the Victa/Valvoine oil...mix
(hopefully avoiding ethanol..another wild card we dont need)

it seemed happy enough, but as you said they arn't such a precision machine
and I guess will take a far amount of abuse
and still chug along

you are so right Bob
they all still have 25:1 on the tank & caps!

"So I think thats what I'll use it at" 25:1
regardless of any claims

Still if I had my thinking cap on I would have realized, as you said... its more an engine thing then an oil thing..
(jetting and metering)

The magic claim or why of 50:1 I guess threw me and was spooked already by the trimmer fiasco

Oh yes I looked a bit more on spark plugs and it, although it can if you go too far out affect performance, & badly
(not it seems were I was aiming for thought in theory, maybe but thin Ice on that one I think mate)

The reasoning is I think more so for, as I read else where
"less possible fouling of the plug" (NGK 4 rather then 6)

CJ8 I used did foul occasionally and ok no mechanic here but do have a little bit of knowledge so easy enough for me but your average yogi bear would be off to the mower shop

so if it happened too often I guess they wouldn't be happy campers

But well time will tell I guess in how many NGK BPMR4A plugs turn up as fouled in use compared to how many CJ8's you might have got
(and nothing else wrong with the mower)

Yes the resister, interference suppression
(not sure how it may affect ignition thought)
more applicable in the days of AM radio I suppose
VHF TV I suppose too..

as I said...this I think was fitted with the RCJ8Y originally
but I couldn't get it at the time and have been using CJ8's...

when I get this project under way I'll post up pictures for comment and advice


Thanks Again Bob,

Cheers all

Its actually a BM6A-CJ8

Not sure what the resisted plug is for NGK


I wont use Champion on anything.