2 STROKE OR 4 STROKE how can I tell the difference

harlley

Recruit
Joined
Jun 21, 2010
Messages
1
I'm new to the boating world..have an older 3.5 Mercury out board but I don't know how to tell which it is...also wondering wher to find a serial # and the age of the motor...thankx for any help...harlley
 

Fuzzytbay

Chief Petty Officer
Joined
Jun 6, 2008
Messages
557
Re: 2 STROKE OR 4 STROKE how can I tell the difference

Well I'd say its a two stroke, as for the serial number, take of the cowling, it should be stamped on the block somewhere. Once you find the number, the year of manufacture can be found.
 

Jacket4life

Petty Officer 1st Class
Joined
Apr 22, 2010
Messages
382
Re: 2 STROKE OR 4 STROKE how can I tell the difference

Look at it this way: Until you can determine for sure, treat it like a 2-stroke. If you mix fuel and run it through a four stroke, all that will happen is you will foul plugs a little more often. (cheap) If, on the other hand, you run a two-stroke without oil, you will quickly burn up the engine (not cheap).
 

bob1340

Petty Officer 1st Class
Joined
Jun 12, 2010
Messages
287
Re: 2 STROKE OR 4 STROKE how can I tell the difference

I think one of the easiest ways to check if it's a 2 stroke is, if the spark plugs and head are on one end of the motor and the carb is on the other end it's a 2 stroke. 4 strokes have the carb on the side towards the head.
 

RicMic

Chief Petty Officer
Joined
May 14, 2010
Messages
431
Re: 2 STROKE OR 4 STROKE how can I tell the difference

Look at it this way: Until you can determine for sure, treat it like a 2-stroke. If you mix fuel and run it through a four stroke, all that will happen is you will foul plugs a little more often. (cheap) If, on the other hand, you run a two-stroke without oil, you will quickly burn up the engine (not cheap).

Well thats true UNLESS its a four stroke without any oil in the crankcase. If its a four stroke, somewhere there has to be a place to add check the crankcase oil under the cowling and if it is, then you need to check that anyway, BEFORE you start the engine.
 

grandpaclint

Petty Officer 3rd Class
Joined
May 15, 2009
Messages
86
Re: 2 STROKE OR 4 STROKE how can I tell the difference

look for an oil filter,and a dip stick=4 stroke
 
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