How can I tell whether 2 cycle vs. 4 cycles engine?

[Kroze]

I have a push lawnmower (Sears) and i'm looking to replace the oil. The problem is that i don't know what oil to get because it have 2 different types (2 cycle & 4 cycles)


Also are all push lawnmower spark plugs universal fit? Other than gap size?

 

[Engineer]

Typically, SAE 30 oil is used for small engines like a lawn mower. 2 cycle oil is to be mixed with the gas and I don't ever recall seeing a 2 cycle oil mower.

 

[skull]

Lawn boys are 2 cycle. If you had a 2 cycle motor it would be locked up by now.

Any spark plug should work. You will need the right gap size.

 

[Bignate603]

Originally posted by: Engineer
Typically, SAE 30 oil is used for small engines like a lawn mower. 2 cycle oil is to be mixed with the gas and I don't ever recall seeing a 2 cycle oil mower.

We had one, I think it was a 'lawn boy' brand mower.

If there's an oil tank full of oil on it just do like Engineer says and use 30 weight oil. If there isn't any oil tank you've got a 2 stroke. However, if you've got a 2 stroke and this is the first you've heard about adding oil to the gas I'd go look at new mowers.

 

[Engineer]

Originally posted by: skull
Lawn boys are 2 cycle.

Didn't know that. Thanks!

 

[Kaervak]

Look on the mower for the oil dipstick, it will have the required oil type listed on it, usually SAE 30. If it's a two cycle it should have a sticker on it somewhere with the oil to gas ratio, like 50:1 or 40:1. 99% chance it's a four cycle.

Spark plugs can differ from mower to mower, since yours is from Sears chances are it's a Craftsman with a Tecumseh engine. They use Champion J19LM plugs. If it's not a Tecumseh, you can always pull the current plug and check the part number on it to get a proper match. The gap for the plug should be 0.30

 

[GuitarDaddy]

If it were 2 cycle you would know it, you have to mix gas with 2 cycle oil for fuel. Generally older lawnboys, weed wackers and chainsaws are the only 2 cycle's. Just use SAE30 4 cycle oil in the crankcase of your mower.

To specifically answer your question, if it has an oil fill it is a 4 cycle.

 

[Engineer]

Originally posted by: GuitarDaddy
If it were 2 cycle you would know it, you have to mix gas with 2 cycle oil for fuel. Generally older lawnboys, weed wackers and chainsaws are the only 2 cycle's. Just use SAE30 4 cycle oil in the crankcase of your mower.

It's interesting that a mower (Lawn Boy) would use a 2 cycle engine. The reason for 2 cycle engines is to have the oil mixed in with the gas so that the engine can be lubricated from the fuel and it will be lubricated no matter which position it's placed in (chainsaw can be turned over, up, down, backwards, forwards and it doesn't matter because the oil is in the gas). Must be some other reason that Lawn Boy would want to do that. Personally, I would hate having to mix oil with the gas to mow the lawn, lol!

 

[Kroze]

Originally posted by: GuitarDaddy
If it were 2 cycle you would know it, you have to mix gas with 2 cycle oil for fuel. Generally older lawnboys, weed wackers and chainsaws are the only 2 cycle's. Just use SAE30 4 cycle oil in the crankcase of your mower.

To specifically answer your question, if it has an oil fill it is a 4 cycle.

Thanks! It does have an oil dipstick.

 

[natto fire]

Originally posted by: Engineer

Originally posted by: GuitarDaddy
If it were 2 cycle you would know it, you have to mix gas with 2 cycle oil for fuel. Generally older lawnboys, weed wackers and chainsaws are the only 2 cycle's. Just use SAE30 4 cycle oil in the crankcase of your mower.

It's interesting that a mower (Lawn Boy) would use a 2 cycle engine. The reason for 2 cycle engines is to have the oil mixed in with the gas so that the engine can be lubricated from the fuel and it will be lubricated no matter which position it's placed in (chainsaw can be turned over, up, down, backwards, forwards and it doesn't matter because the oil is in the gas). Must be some other reason that Lawn Boy would want to do that. Personally, I would hate having to mix oil with the gas to mow the lawn, lol!

Well, 2 cycle engines tend to have higher specific output as well, so a lighter engine can make more power. I am pretty sure the lawnboys that had them had small 20" or less decks. Perhaps they were going for light weight?

 

[Zenmervolt]

Originally posted by: Engineer

Originally posted by: GuitarDaddy
If it were 2 cycle you would know it, you have to mix gas with 2 cycle oil for fuel. Generally older lawnboys, weed wackers and chainsaws are the only 2 cycle's. Just use SAE30 4 cycle oil in the crankcase of your mower.

It's interesting that a mower (Lawn Boy) would use a 2 cycle engine. The reason for 2 cycle engines is to have the oil mixed in with the gas so that the engine can be lubricated from the fuel and it will be lubricated no matter which position it's placed in (chainsaw can be turned over, up, down, backwards, forwards and it doesn't matter because the oil is in the gas). Must be some other reason that Lawn Boy would want to do that. Personally, I would hate having to mix oil with the gas to mow the lawn, lol!

Live in a hilly area? Until the recent advent of mower engines with full pressure lubrication you could easily kill a lawnmower by using it on a hill that was too steep. This isn't so much an issue with riding mowers because hills that steep would cause the mower to flip over or simply slip, but a pushmower can be used on some pretty steep hills and this can cause oil starvation issues with 4-cycle engines.

ZV

 

[Perknose]

Originally posted by: Captain Howdy
Well, 2 cycle engines tend to have higher specific output as well, so a lighter engine can make more power. I am pretty sure the lawnboys that had them had small 20" or less decks. Perhaps they were going for light weight?

They're also simpler and cheaper to manufacture.

 

[Engineer]

Originally posted by: Perknose

Originally posted by: Captain Howdy
Well, 2 cycle engines tend to have higher specific output as well, so a lighter engine can make more power. I am pretty sure the lawnboys that had them had small 20" or less decks. Perhaps they were going for light weight?

They're also simpler and cheaper to manufacture.

True. No valves, cams, etc. However, I wonder if they are more or less efficient in that it would seem that the incoming fuel would be mixing with the remaining exhaust fumes that are left in the cylinder (4 stroke model obviously removed more as it has an exhaust stroke).

 

[GodlessAstronomer]

What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

 

[Engineer]

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

I used both terms in my above posts, lol, but I guess the "2 cycle oil" and the OP's title threw me off!

Sorry, won't happen again ole godless one!

 

[GodlessAstronomer]

Be sure it doesn't :|

 

[Engineer]

Originally posted by: GodlessAstronomer
Be sure it doesn't :|

Just for that, I'm going to go (in my saddened state) and eat one of those delicious meatballs that I made earlier! :|

:shocked:

 

[Bignate603]

Originally posted by: Engineer

Originally posted by: Perknose

Originally posted by: Captain Howdy
Well, 2 cycle engines tend to have higher specific output as well, so a lighter engine can make more power. I am pretty sure the lawnboys that had them had small 20" or less decks. Perhaps they were going for light weight?

They're also simpler and cheaper to manufacture.

True. No valves, cams, etc. However, I wonder if they are more or less efficient in that it would seem that the incoming fuel would be mixing with the remaining exhaust fumes that are left in the cylinder (4 stroke model obviously removed more as it has an exhaust stroke).

2 strokes tend to be less efficient in terms of fuel consumption and pollute more for the same amount of power. Having the intake and exhaust opened at the same time means that some fuel bypasses the combustion chamber.

 

[GodlessAstronomer]

Indeed, in some places (such as my country) there is now a ban in place on producing new two stroke boat engines due to the horrible emissions. You only need to be near a 2-stroke boat, Jetski or lawn mower to confirm the strong odor of unburned hydrocarbons. Nasty.

 

[Engineer]

Originally posted by: GodlessAstronomer
Indeed, in some places (such as my country) there is now a ban in place on producing new two stroke boat engines due to the horrible emissions. You only need to be near a 2-stroke boat, Jetski or lawn mower to confirm the strong odor of unburned hydrocarbons. Nasty.

After spending a few hour with the chainsaw (because of the recent ice storm), I agree 100%. I was so damn sick from the fumes..... :barf; and :dizzy; emoticons here.

 

[Zenmervolt]

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

Welcome to the wonderful world of colloquialisms. Throughout the US the terms "2-cycle" and "2-stroke" are interchangeable in the common vernacular. At least in the US, it is rather excessively pedantic to insist that only "2-stroke" is correct.

ZV

 

[Engineer]

Originally posted by: Zenmervolt

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

Welcome to the wonderful world of colloquialisms. Throughout the US the terms "2-cycle" and "2-stroke" are interchangeable in the common vernacular. At least in the US, it is rather excessively pedantic to insist that only "2-stroke" is correct.

ZV

Curious, why is it called "2 Cycle Oil" instead of "2 Stroke Oil"?

Even oil companies call it 2 cycle and 4 cycle!

 

[Zenmervolt]

Originally posted by: Engineer

Originally posted by: Zenmervolt

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

Welcome to the wonderful world of colloquialisms. Throughout the US the terms "2-cycle" and "2-stroke" are interchangeable in the common vernacular. At least in the US, it is rather excessively pedantic to insist that only "2-stroke" is correct.

ZV

Curious, why is it called "2 Cycle Oil" instead of "2 Stroke Oil"?

Even oil companies call it 2 cycle and 4 cycle!

You're agreeing with me.

ZV

 

[Engineer]

Originally posted by: Zenmervolt

Originally posted by: Engineer

Originally posted by: Zenmervolt

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

Welcome to the wonderful world of colloquialisms. Throughout the US the terms "2-cycle" and "2-stroke" are interchangeable in the common vernacular. At least in the US, it is rather excessively pedantic to insist that only "2-stroke" is correct.

ZV

Curious, why is it called "2 Cycle Oil" instead of "2 Stroke Oil"?

Even oil companies call it 2 cycle and 4 cycle!

You're agreeing with me.

ZV

Actually, you're both right. While it may be thrown around as 2 cycle, it's actually 2 stroke (single cycle actually) as GA stated. So I agree with you both! :shocked:

 

[sao123]

Originally posted by: Engineer

Originally posted by: Zenmervolt

Originally posted by: GodlessAstronomer
What's this 2/4 'cycle' shit? It's a 2/4 stroke engine. The cycle refers to the full cycle of the engine, so a 2 stroke engine has 2 strokes per cycle, a 4 stroke has 4 strokes per cycle (much like uhohs).

Welcome to the wonderful world of colloquialisms. Throughout the US the terms "2-cycle" and "2-stroke" are interchangeable in the common vernacular. At least in the US, it is rather excessively pedantic to insist that only "2-stroke" is correct.

ZV

Curious, why is it called "2 Cycle Oil" instead of "2 Stroke Oil"?

Even oil companies call it 2 cycle and 4 cycle!

because 2 stroke oil is used for "something else"