Is 100:1 gas/oil ratio safe for my 2-stroke Yamaha?

[Quadrille in JB]

Thanks in advance, I’m looking for some knowledgeable advice.
I currently have an older two-stroke 8 hp Yamaha for our 8’ Caribe RIB. The motor has a placard that says 100 to 1. Them manufacturer probably recommended this very lean ratio to pass the EPA emissions tests of the day.
The engine is in great shape and runs well so I’d hate to destroy it by running too little or too much oil in the fuel.
I’m aware from my motocross days that too much oil leans out the fuel/air mixture.
Does anyone have experience running this lean a fuel/oil mixture?
I know 50:1 was used for many years. I’m thinking of maybe 75:1 as a safer alternative to the 100:1 fuel/ oil mixture.
Any ideas from this great source of information?
Thanks

[BilNan]

I have used AMSOIL Marine Outboard 100:1 premix oil, it’s been around since 1973.
It has been tested to as little as 300:1 without any damage to engine.
You can find info here:
http://synthetic-performance.wboil.c...front/ato.html

[Compass790]

I don't KNOW but my guess is the same as yours. I THINK the 100/1 ratio is for emission reasons. We have a 2hp Yamaha that says 100/1 but we always use 50/1 & have been using it for about 7 years, (was bought used) with no issues. Had to clean the sparkplug once in that time & use the motor lots to go to dive spots.
Pretty certain you will get less wear at 50/1, probably more carbon buildup but easier to decarb than rebuild is my reasoning for running 50/1. just my 2c worth tho.

[a64pilot]

I’d run it at 50 to 1, I think your exactly right.
It’s not going to lean it out enough to matter, it also lowers the octane of the fuel, but I don’t think it’s enough to matter.
I’ve noticed that the Yamaha 15 HP leisure two stroke recommends 100 to 1, but the Enduro is 50 to 1 I believe. I have to assume it because they expect the Enduro to be used more as a Commercial engine being run a lot and run harder than the Leisure motor.

Run a good oil and I don’t think you will ever be cleaning carbon out of it. I never have, except back in my Hare Scrambling days when we ran either vegetable oil or bean oil, not salad oil of course, Hi-point oil.

Remember this stuff, or at you not old enough?
https://www.ebay.com/itm/Vintage-Mot...-/312003956904

[mikeo16]

I have same 8hp engine that I bought new. The mechanic who walked me through the care and operating instructions told me to always use 50 to 1 mix. He said to ignore the 100 to 1 label - he said nothing has changed since the older outboard with the 50 to 1lables

[HankOnthewater]

I had four 2-stroke Yamahas (3 and 15 HP), all prescribed 100:1 ratio, I have always used 50:1, or 60:1 . Never had a problem with any of these engines. Maybe it makes sense, for the engine, maybe not for the environment.
BTW I have seen several people running 4 stroke outboards and using 100:1.

[Quadrille in JB]

Thanks for the prompt replies. It sounds like we all agree on the 50:1.
And yes I’m old enough to remember bean oil. I ran the Husky/Penton shop in Stuart, Fl for 5 years in the early 70’s and raced every hare scrambles and enduro in Fla and South Ga for that time frame. I ran a 450 Husky and a 250 Penton.
Do you remember Blenzoil Gold Label? 2oz bean oil and 12 oz of nitro methane for each gallon of high test. It was expensive but gave a great hp boost, and the guy’s eyes behind you burned so badly from the nitro that they were no competition.

[FlyingScot]

I run my 2008 Enduro 15 @ 50:1 using Yamalube Semi Synthetic https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Presumably Yamaha changed the recommendation for emissions and/or lower consumable costs.

[Compass790]

We like the full synthetic 2 stroke oil in the outboard
ahh the smell of the Maico 400 running Castrol R40 castor oil, it was great. I believe you can still buy it here in NZ ( the oil not the Maico. lol )

[a64pilot]

I ran a Husqvarna WR 250 in Hair Scrambles near and around Chattanooga Tn. Mine was a 73 model I think, the year before the radial finned head and lay down shocks.
But yes I remember the bean oil and nitro, never ran it though.

If you guys don’t mind a little trivia drift, but does anyone know what Husqvarna means, and what the symbol represents?

[BilNan]

AMSOIL sells a 100:1 Marine Outboard Oil that has been around since 1973, they still sell it and it hasn’t caused any problems. Here is a link to their page:
https://www.amsoil.com/shop/by-produ...D=3&zo=1858763
Sells for under $15 per quart and at a 100:1 should last a long time.

[ggray]

I use Amsoil 100:1 oil, mixed about 90:1. My 30 hp Tohatsu drips unburnt oil, and makes a mess, so I want to keep the oil at a minimum.

The original location of Husqvarna is Huskvarna, Sweden. I'm thinking it's on the shore of a lake with the same name.

I've been there looking at nearby wood processing facilities. Until I just checked my memory with an internet search, I had thought they were spelled the same.

[carstenb]

Originally Posted by a64pilot

I ran a Husqvarna WR 250 in Hair Scrambles near and around Chattanooga Tn. Mine was a 73 model I think, the year before the radial finned head and lay down shocks.
But yes I remember the bean oil and nitro, never ran it though.

If you guys don’t mind a little trivia drift, but does anyone know what Husqvarna means, and what the symbol represents?

Husqvarna

Husqvarna (pronounced [²hʉːsˌkvɑːɲa]) is a Swedish company founded 1689 to produce muskets. The company has grown since, was partitioned, and is now a brand of multiple companies

I speak danish and translating it ot danish it wuld mean a "house churn" or something close to that - maybe they made milk churns once upon a time.

I just bought a tohatsu 2 stroke 9.8HP they say 50 to 1 during break in thereafter 25 to 1

[GordMay]

Greetings and welcome aboard the CF, BilNan.

I believe that Huskvarna is just a place name, as previously noted.

[a64pilot]

Originally Posted by carstenb

I speak danish and translating it ot danish it wuld mean a "house churn" or something close to that - maybe they made milk churns once upon a time.

I was sponsored by Husqvarna way back when and went on a ride with some of the factory riders, I was told it was “house grinder” closest English translation, but the company had a rich history of manufacturing “house machines” good sewing machines, refrigerators I think and things like that.
They actually manufactured the bikes at a loss to the Company, but gained prestige and got exposure from it.

Funny thing is this isn’t apparently well known as I couldn’t find it on Google and had begun to wonder if it was true, but you confirmed it.

The emblem is actually a gunsight. Way back in the day apparently the company began as a firearms manufacturer, and if you look down the barrel of many Military gun sights, the outside two blades on the emblem are the rear sight blades, and the middle the front.
This also isn’t found with a Google search, I assume they don’t want that kind of presence

Every heard of the Brit motorcycle manufacturer BSA? Know what BSA stands for?