2 stroke oil question: Bike vs Boat lube

[Benjamin_Jones]

Hi all!

Just a silly question... As usual...

What would the technical reason be for not being able to use 2 stroke boat oil in bikes (air or water cooled) or viceversa?

I'm talking of both pre-mixed and autolube systems.

Synthetic and mineral oil types.

For this query, let's disregard emissions, for now. Also the comparitive pricing of the oils.

Boats are generally 50:1, bikes run on 25:1 up to 32:1.

If possible to use boat oil on a bike, would I stick to bike's ratio?

Bike oil in a boat, what ratio?


I'm not looking at being shot down in flames here, I'm sure there are hundreds of people out there that has either asked this question without a logical answer or has not thought this far yet.

It's just a curiosity question...



Many thanks guys!

Spring has sprung and the boating season is looking good!

Regards from a hot Johannesburg in South Africa!


Benjamin.




Check the thread:
http://www.marineengine.com/discus/messages/12479/219566.shtml

 

[heavyhitter]

lol, spring starting where you are and winter starting where I am.

I have used and owned 2 strokes for many years from dirtbikes, ATV, boats and power tools.

The main difference is the certification labeling. Some applications require a different spec oil. Just like cars. If your bike and or boat require the specific type of oil just get the oil that meets that specification for both applications.

The ratio's such as 50:1 and 32:1 etc has nothing to do with the type of oil just the ratio of oil used per gallon/liter of gas.

This is an excellent article http://www.snowgoer.com/output.cfm?id=1051903

It compares snomobile oil to boat oil. Where it says "snowmobile" replace that with "dirtbike" and you will have your answer.

To sum it all up for example:
Say you have a "dirtbike oil" that is TC-W3 rated. Put if your boat motor recommeneds TC-W3 then yes it will interchange or vice versa.

Two stroke oil is ment to do the same in every application howerver add packs can be different for different demands.

Example a boat motor usually stays at a specific RMP range for long periods. While a dirtbike can rev to the moon and back and the RPM's are always changing.

Hope this helps

 

[wileyE]

Bike oil usually uses a low ash detergent better for it's cyclic use. Boat oils use ashless dispersant to avoid plug fouling from the metallic ash that may build up during constant run speeds. From a lubricity standpoint both will do the job if used at the proper ratio. Pre mix only oils are usually heavier in viscosity so may give some more protection than injector oils (even if the label says for premix or inj). If your mixing with injector oil you may want to up the ratio a bit. I've seen some crazy mod 2 strokes from big name engine builders run on cheap tcw3 oil, the key is they put a lot of oil though them.

 

[RC46_Rider]

Hi,

Heavyhitter gave a good, clear explanation of the differences of "intent" and design of the two types of oil. I also have heard directly from a major brand oil producer that the primary difference is in the ENGINE APPLICATION of these oils. Briefly: 2 stroke outboards are water cooled and operate at lower temperatures, lower RPM and lower specific HP outputs than most motorcycle engines (full blown racing outboards are another ball game, and are not really a "design target" of "retail" outboard motor oil). Boat motors also do not have the "exhaust power valves" that most modern 2 stroke dirt bikes have. A 125cc or 250cc motocross bike operates at much higher rpm and higher temperature and the engines produce much more HP per cc than an outboard motor, so "typically" a heavier base oil is used in bike oil, usually an SAE 30 or 40 oil + additives. A few off road bike oils use an SAE 20 base to supposedly, reduce off throttle plug problems, but most use a heavier base oil because of the high specific HP outputs. Also, my understanding is that many current bike oils have extra detergent to keep the "power valve" (moveable exhaust port)cleaner. Additionally, many recreational 2 stoke motorcycles are AIR cooled and operate at a much higher temperature than a water cooled outboard, thus also requiring a heavier base oil. Outboard oils contain more anti-corrosion and rust inhibitors because of the nature of the high humidity "always wet" environment boats are in when not in operation. (This could be an advantage for a land based engine that is used infrequently) The lower operating temperature of a water cooled outboard also changes the oil design needs. I would hazard a guess, you might have a few more plug fouling problems if you used some motorcycle oils in an outboard...but who knows... So, as you can see, there really is a difference in ENGINE application and the two oils are designed accordingly.

Now, that said, assuming a good quality oil, they seem to be pretty compatible in the real world. My son races a KTM200 dirt bike in Hare Scrambles and he has used both premium quality bike oils and premium quality semi-synthetic TW-3 2 stroke boat oil. We could not tell any significant difference in that application, but in Hare Scrambles, you are not facing long periods of full throttle operation and the KTM200 is a liquid cooled motor, somewhat similar to a boat engine. That said, I would NOT run a boat oil in a road racing bike that operates for long periods at full throttle....I would stick with a real motorcycle oil and probably the same in a motocrosser. In a mildly tuned 2 stroke street bike, I suspect both would work OK. You would probably have to do some pretty extensive tests to really see what, if any difference there was in engine life and other issues.

I guess if you wanted to summarize the differences in the two types of oil, I think you would say that in an extreme environment (i.e. high temperatures and high RPM) the motorcycle oil would be better in terms of engine protection and better resistance to piston seizure, etc. In a milder land based application, I doubt there would be much difference, especially between a cheap motorcycle oil and a 2 stroke boat oil...actually, a premium quality (semi-synthetic) boat oil is probably better than a cheap motorcycle oil!

Everybody wants to "save money", but unless your financial situation is extreme, it seems to me that the RATIO of the cost of oil to the cost of the VEHICLE says that it make sense to use the oil that is INTENDED for that vehicle in it. There IS a reason for the two types of oil and they are different.

Bottomline: "YOUR CALL!!" I would guess that unless you have a fairly extreme or demanding engine application you could use either...assuming good quality oils.

Regards, RC46 rider