2 stroke oil?

UsernameAlreadyExists

OK, I think I understand engine oils in terms of the gradings, magnetic additives, and natural/semi/fully synthetic, and brand name premiums etc ... but I know nothing about 2 stroke oil.

Given that my only experience of 2 stroke has been with mopeds, and that it seems to serve the purpose of acting as a lubricant and getting burnt off, any old crap should do.

Now I've learned that in Halfords you can buy moped 2 stroke oil, and you can also get garden machinery 2 stroke. What's the difference?

I actually need some 2 stroke for a 140Hp outboard motor that was probably built in the 1980s.

Do I need to pay the premium prices that seem to be charged in chandleries for specialist marine 2 stroke oil? If so, why?

forgotmyname

The synthetic moped stuff burns cleaner so less fouling of the sparkplugs and sooting everything up.

The cheaper garden machinery doesnt really matter if it fouls up the sparkplug after a couple of hours use.

But stopping every 2 hours on the road maybe too much trouble.

justjohn

lol I use motorbike premium 2 stroke on my chainsaw.... I got it cheap...never notice any difference so far ...

Iceweasel

I have no idea why the marine stuff should be so expensive.

I use the cheapy Halfrauds garden engine 2-stroke in my little old Honda outboard on an old fishing dingy,

I check the spark plug after every 5 trips or so and never have a problem with soot.

The Halfrauds stuff is marked as low-ash.

But if you're in any doubt about the quality of it then go for Castrol Actevo Scooter/Moped 2-stroke oil - only a £1 or so dearer and they sell it in Tesco, Asda etc.

That's what I would use if I had a bigger / more expensive / higher revving outboard.

Chris_Hinds

Marine oil will be more expensive because of the duty cycle the engine is under.


Think about when you drive a car or bike capable of 100mph at say 60mph along a typical road. You have points of going downhill (so no power on), points of going up hill (some power on), points of going flat (a little power) and you overtake another slower driver (full power on).


A boat behaves more like an aircraft, the load is constant to maintain a given speed. So a boat running at 60% of maximum speed will be running at about 60% of maximum power - call it 85Hp for your boat. Under such conditions the engine is producing more power and more heat as well as running faster than a typical car engine.


More expensive oils will break down less under high temperature conditions and continue to protect the engine.

facade

Marine oil has anticorrosion and antiscuff additives, and is designed to burn cleaner at the lower temperatures of a watercooled engine.

Does it really matter? I've no idea.

Would I put it in my outboard? Yes, for one I don't fancy changing the plugs in the middle of the English Channel.