Evinrude oil ratio?

I recently bought a evinrude 4hp lightwin. I believe it's a 1975. Any idea what I should be mixing it at? The guy I bought it from said 70:1 but I've been around 50:1 and 60:1 just to see how it runs. Any input? Thanks!

50:1.
You are not doing the engine any favors at all by using any less oil in it.
If you are planning on running it in the thick stuff then by all means run extra oil as well.

Also when I put the boat with the outboard in my truck I usually tilt it up for the ride home and by the time I get home where is a small puddle of fuel in the lower cowel, not a lot, just a small amount. Is this normal being that the motor is tilted?

normal.

Any reason to not run the fuel out prior to packing?

I was told running the cylinders dry was not a good idea considering the gas and oil is what keeps them lubricated, I do it on my dirt bikes but I wasn't sure if it was a good idea on these motors

50:1 and the oil/gas won't evaporate fast enough to dry things out unless your storing it for years.

So running it dry before I pack up is a smart choice in this case?

azfish1121 said:

So running it dry before I pack up is a smart choice in this case?

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If it were me I would, I just got done re-ringing a 25 that had sat for a few years and there was still a good coating of oil on the pistons,crank and rods. Like whats been said 50:1 and a little extra oil never hurt a darn thing. The PO always ran all the fuel out when he was done for the day.

Never run more oil than the manufactures recommendation. Excessive oil causes excessive carbon buildup. This excessive buildup around the piston rings and grooves can lead to a stuck ring in a piston groove then a scuffed cylinder and eventually a badly damaged cylinder. Rebuild time.

Sure you didn't mean don't run less than the manufacturers recomendation. :twisted:

The worst thing you will do if running extra oil is carbon up (de-carb is easy).
The worst thing you will do if running lean oil is buy a new motor.

I run 24:1 motors closer to 20-16:1.... little more carbon, but makes the seafoam day more fun.

50:1 motors I normally run between 40-50:1. I wouldn't even feel bad about going down to 30:1.

nowgrn4 said:

Never run more oil than the manufactures recommendation. Excessive oil causes excessive carbon buildup. This excessive buildup around the piston rings and grooves can lead to a stuck ring in a piston groove then a scuffed cylinder and eventually a badly damaged cylinder. Rebuild time.

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Oh Good Lord - You couldnt be further from the truth if you tried!!!

I run 13.oz. oil per 5 gal of fuel so technically I guess I'm over oiling too. That's 2.6 oz. per Gal. 50:1 is 2. 56 oz. per Gal. precision measured with an old plastic baby bottle. :mrgreen:

If you think the outboard manufactures are morons and you don't adhere to their oil ratio recommendations and run way too much oil then please run engine tuner every 50 hours (another manufactures recommendation) to break up the excessive carbon buildup. Stuck rings are bad news.

I hope this is not evolving into an oil thread. :shock:

If it does evolve into an oil thread.....you may actually learn something.

When I was a lad I had an oil head problem. Seemed if I did not wash my hair daily it would get rather nasty.

Come to think of it the oil problem was not limited to my head.

Sad times. :LOL2:


oh, my bad ya'll said oil thread not oil head.

:mrgreen: :mrgreen: :mrgreen:

nowgrn4 said:

Never run more oil than the manufactures recommendation. Excessive oil causes excessive carbon buildup. This excessive buildup around the piston rings and grooves can lead to a stuck ring in a piston groove then a scuffed cylinder and eventually a badly damaged cylinder. Rebuild time.

Click to expand...

Heres the 25 I was talking about.






nice coating of oil every where, no stuck rings, no carbon build up at the tops of cyls. This was another motor that was on a 21 ft hand built wooden work boat. Don't know how much it weighed but it took 8 men to flip it over so the owner could scrape and repaint the bottom.
The engine was ran hard for years and always with a bit extra oil and a some seafoam.