Mercury 40 hp 2 stroke vs 4 stroke cycle

[13whaler13]

I have a 2001 40 hp Mercury sn:0t227383. I have a service manual titled Models 30/40 (2 cylinder) and is for n: 0G044027. The manual states on specification page that engine is a 4 stroke cycle. Searching for parts I have seen that the engine is a 2 stroke. Do I have the right manual and what is the difference between 2 stroke and 4 stroke cycle.

 

[JB]

Re: Mercury 40 hp 2 stroke vs 4 stroke cycle

Howdy, 13whaler13 :welcome:

There are many differences between 2 and 4 stroke cycle engines, enough that you don't want to use the manual for one to maintain the other.

If you do, in fact, have a 4 stroke manual and a 2 stroke engine, you have a mismatch.

 

[waynelk]

Re: Mercury 40 hp 2 stroke vs 4 stroke cycle

A 2 stroke will have an oil tank which will inject oil into the fuel. They have no valves and typically smoke when you start them. A four stroke has valves and will have an oil reservoir inside the engine with a dipstick to check level. On a 2 stroke every time the piston goes up and down it fires. (Hence 2 stroke) On a 4 stroke the piston goes up and down for exhaust then up and down to add gas and fire. (Hence 4 stroke) Because of the cam and valves they are heavier but better on gas.