piston orientation 4.5hp Evinrude 1980

raczekp1

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Mar 30, 2010
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1,327
i did the carb job, took out pistons, but i didnt pay atention which side should i put them back.
isnside piston are 2 marks( mark looks like arrowhead, and letter "L")
so "L" means low, and this side down?
 

jonesg

Admiral
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Feb 22, 2008
Messages
7,174
Re: piston orientation

Re: piston orientation

No wonder you got no reply.
What yr, hp and model engine.

When you say pistons, is that needle valves?
 

boobie

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Nov 5, 2009
Messages
20,826
Re: piston orientation

Re: piston orientation

Better explain yourself better if you want any replies.
 

Mas

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Oct 3, 2006
Messages
1,656
Re: piston orientation

Re: piston orientation

If you're looking at the "pistons," the "L" means loose side to remove the wrist pins...which there is no reason to remove. Still wondering why the pistons were removed? "Carb job" meaning carburator???? Or, "carb job" meaning removing built up carbon on the piston/rings/head??? If it's the later, there is an easier way with products like "seafoam," which do not require powerhead teardown.

Mas
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: piston orientation

Re: piston orientation

The piston only goes back in the engine one way. The dome on the top of the piston must be in a specific orientation. The rod must also be correctly oriented. The small oil hole on the piston end of the rod must be facing upward during reassembly. That makes the rod/piston assembly either a right or a left. If you are asking these questions during reassembly, I'd suggest you get a factory service manual.
 

raczekp1

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Mar 30, 2010
Messages
1,327
Re: piston orientation

Re: piston orientation

i took out pistons becouse i had stuck rings in one piston.
puting back i tought its good idea to put new rings at both pistons.
for me its not posible to get service manual

i'm working with 4.5hp Evinrude 1980,

i think this solution with piston orientation is the same as 6 hp, 7.5 hp, 9.9hp becouse spark plugs are locateg at the same side of head.
 

SolingSailor

Petty Officer 2nd Class
Joined
Dec 24, 2009
Messages
197
Re: piston orientation

Re: piston orientation

The top of the piston will have two slopes. The steeper slope goes toward the intake ports. The lesser slope orients towards the exhaust ports. If there is an oil hole in the connecting rod, it must go upwards.
 

emdsapmgr

Supreme Mariner
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Dec 9, 2005
Messages
11,551
Re: piston orientation

Re: piston orientation

Yes, I must have been thinking of another engine...sorry for the misleading comment.
 

raczekp1

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Mar 30, 2010
Messages
1,327
Re: piston orientation 4.5hp Evinrude 1980

maybe someone can add some photo, how should it look.
i'm thinking it should look like this one
 

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SolingSailor

Petty Officer 2nd Class
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Dec 24, 2009
Messages
197
Re: piston orientation 4.5hp Evinrude 1980

That photo looks correct to me. A service manual would tell all.
 
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