Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

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skyegospel

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Aug 17, 2008
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Hi there. I have never owned an outboard before and have just bought a wee Plymouth Pilot with a 5hp Johnson outboard on eBay.

I am wanting to double check the fuel/oil ratio for the outboard in case I end up causing problems. The man I bought it from told me it should be 100:1 ratio but having looked around internet that seems to be quite high and I just wanted to double check it. I am not yet sure of the model of engine or year or anything like that - just that it is 5hp. I have attached a photo (if I have managed to do it right!)

Many thanks for your help.
 

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Vic.S

Vic.S

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Re: Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

There should be a plate on the transom bracket with the model and serial numbers on it. The model number will identify the exact year.

For a short period in the 1980s 100:1 was the fuel mix but OMC later changed that and all engines post 1964 should be run on 50:1. Use a 2stroke outboard engine oil to TCW3 specification
 
CATransplant

CATransplant

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Re: Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

Definitely 50:1. That 100:1 deal was a mistake on OMC's part, and they later corrected it.
 
wbeaton

wbeaton

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Re: Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

Looks like a 1987. 50:1.
 
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skyegospel

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Re: Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

Many thanks to you for your replies - I will put in 50:1. Can I just check, am I right in saying that the worst that could happen if this is too much oil is that the spark-plug will need replacing?
 
B

BaitThrower

Petty Officer 2nd Class
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Jul 17, 2008
Messages
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Re: Fuel Ratio Question for newbie owner of Johnson 5hp (picture included)

Basically yes. More oil means potentially quicker spark plug fouling. But stick with 50:1 and your cylinders will love you :D
 
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