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Outboard/small engine question
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So I decided a while back to buy a Scott motor. It was $25 and the guy said it worked two years ago. I thought what the hell, I'll take a flyer on it.

As it turns out it's a 1957 Scott 10HP.

Anyway, that was in the winter. FIL and I are just getting around to it now.

We cleaned it all up, it was pretty grimy. And put in new spark plugs. A friend got it going with a drill. Since then we've been able to get it going with one pull. This thing is incredible.

Here's the issue. It's as smokey as a 1970s donut shop.

The manual says to use a 16:1 gas to oil ratio (which we did). I read that that is based on 1957 oil and that you can use a higher gas content ratio with today's oil.

So how high can I make the ratio? 25:1? Please watch the video, do you think the issue is as simple as too much oil?

Would a gunked up carburetor cause this? We haven't looked at it yet.

Anyway, any suggestions are welcome.

As you can see by the water it spewed out a whole bunch of crap the first time it started up.



How does Danny Hart sit down with balls that big?
Last edited by: BLeP: Aug 22, 17 5:24
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Re: Outboard/small engine question [BLeP] [ In reply to ]
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Plenty of suggestions from enthusiast sites. These guys are very helpful.

From another site


"I have an 1955 5.5hp Johnson. Great little motor!
I too was worried about the cloud of smoke, So I inquired on the Antique Outboard Motor Collectors club web site.
They reccomended staying with the 16/1 ratio
Because the motor has bronze bushings instead of
needle bearings.
Try a synthetic oil rated "TCW-3". It smokes less and it is enviromentally friendly.
Remember Oil is cheap insurance."


Outboard collectors club

May be helpful.

A false humanity is used to impose its opposite, by people whose cruelty is equalled only by their arrogance
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Re: Outboard/small engine question [BLeP] [ In reply to ]
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Loads of small hp outboards had bronze bushings instead of needle bearings into the 1960's or early 70's when 50:1 was the recommended ratio.

Do yourself, the air, water and the engine a favor and use a good TCW-3 oil, alcohol free gasoline and have at it.

16:1 or even 25:1 is simply overkill and will potentially foul the plug, make the rings stick and in general carbon up the engine without any off-setting benefit.

I owned a boat dealership in the 1980 and saw a crap-load of these old relics from the 1950's come through the shop. We ran every one of them on 50:1

I'm pretty sure if I dug long enough I could locate the OMC technical service bulletin that discussed going to the leaner oil/ gas ratio.
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Re: Outboard/small engine question [BLeP] [ In reply to ]
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This brought back memories of when I was a kid at our cottage. One summer my Grand-Father and I completely took apart and reassembled an old Johnson 2.5 Horsepower motor. We fired it up after the re-assembly, just as you had here, with the motor on an outboard motor stand, and the lower-unit submerged in a garbage can!

When I was 10, as a birth-day gift, my parents bought be a 6 HP Viking outboard motor for a small aluminum boat we had - It was total freedom as a kid at the cottage - my own boat and motor! Back then you could fill up the gas tank for $5!!


Steve Fleck @stevefleck | Blog
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