Is this a 2 stroke or 4 stroke outboard?

ready4itall

Seaman Apprentice
Joined
May 4, 2015
Messages
49
1979 Evinrude 140hp
Model No. 140943R

Can't find online if its a 2 or 4 stroke. Thanks in advance
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,802
That would be a 2 stroke engine.------Best to find an owners manual.---Read it .------Then think about launching and turning the key.
 

jbcurt00

Moderator
Staff member
Joined
Oct 25, 2011
Messages
25,179
I suspect Vic meant sevice manual, not owners manual, and it IS the manual you want.

Ready4, there may have been an owners manual for the motor, but its not going to provide much helpful info. Look for the service manual Vic referenced.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Since you have no idea how to tell whether an engine two or four stroke, here goes: Look at the engine cover. If it is a four stroke (especially older ones) it will say so on the cover. If that doesn't work remove the engine cover. Most small to midrange HP two strokes will have a plastic oil container on the side of the engine. TWO-STROKE oil is put in this reservoir and it is mixed automatically with the fuel. Some two strokes have a separate oil container mounted at the stern of the boat near the engine. If the engine is a four stroke, you will find a dip stick like the one on your car (you do check that once in awhile -- not????). On a four stroke, engine oil goes into the crankcase. A four stroke engine will also have a valve/cam cover just like your car. Two strokes have a very flat cylinder head where the spark plugs screw into. Four stroke engines have spark plugs that are generally screwed in at an angle. If you still can't tell -- then before you even attempt to operate this boat, have someone who does know the difference show you how to check and operate it.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,020
Not sure there were many 4-stroke outboard motors in '79
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,802
Homelite / Bearcat was one brand of 4 stroke motors in the early days.------------Best for the poster to educate himself or learn about boats / motors the hard way.----------That is through an empty wallet !!
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,868
Since you have no idea how to tell whether an engine two or four stroke, here goes: Look at the engine cover. If it is a four stroke (especially older ones) it will say so on the cover. If that doesn't work remove the engine cover. Most small to midrange HP two strokes will have a plastic oil container on the side of the engine. TWO-STROKE oil is put in this reservoir and it is mixed automatically with the fuel. Some two strokes have a separate oil container mounted at the stern of the boat near the engine. If the engine is a four stroke, you will find a dip stick like the one on your car (you do check that once in awhile -- not????). On a four stroke, engine oil goes into the crankcase. A four stroke engine will also have a valve/cam cover just like your car. Two strokes have a very flat cylinder head where the spark plugs screw into. Four stroke engines have spark plugs that are generally screwed in at an angle. If you still can't tell -- then before you even attempt to operate this boat, have someone who does know the difference show you how to check and operate it.

And some two strokes, like your 1979 Evinrude, have neither an oil tank under the cover or external reservoir. These require oil to be mixed in the gas. They usually have warnings in the starting instructions on the engine and on the fuel tanks, assuming manufacturers tanks are used
 
Top