Why did OMC like the number 8?

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jrs_diesel

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Just a curious thought that occurred to me. I see lots of posts here about 18, 28, 48, 88, etc, HP engines. Why the number 8 instead of an even number? Just seems a bit odd to me.
 

JB

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Re: Why did OMC like the number 8?

Last time I looked 8 was an even number. :)

Each of those engines was a lower price version of the outboard rated 2HP higher. They "derated" them only 2HP so they still met the spec without actually detuning them.

So, the 18 was a 20 less some feature(s), the 88 was a 90, ,etc.etc.
 

yorab

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Re: Why did OMC like the number 8?

Also note: "seems a bit odd to me." :)

But seriously, that's quite a sneaky manuever.
 

boobie

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Re: Why did OMC like the number 8?

The "8" numbers had less goodies on them and were strictly a sales pitch thing.
 

emdsapmgr

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Re: Why did OMC like the number 8?

Boobie's right. The same engine as the 2 hp higher engines. They did not have VRO and usually did not have power trim. Sold as an inexpensive alternative, to hold the sell price down.
 

jrs_diesel

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Re: Why did OMC like the number 8?

That makes sense. Thanks guys :)

Doesn't seem so odd now :D
 

Chinewalker

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Re: Why did OMC like the number 8?

All true, with the exception of the 18. It was never a detuned or derated anything. It started life in 1957 as an improved version of the 1956 15hp. 2 more cubes helped it make 3 more horses. It simply wasn't strong enough to warrant a 20hp tag, but it was certainly stronger than the 15 it replaced, so it was designated an 18...
 

1946Zephyr

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Re: Why did OMC like the number 8?

I think the later 20hp is just an 18 with a slightly larger carb, isn't it? The carb on the 20 was 379032 and on the 18, it was 278402.

As far as the 28 goes, (1960's) that was basically a re-birth of the 1956 30, with an updated fiberglass cowling. Cubic inch displacement was still the same, but there was a different carb here too.

It looks as though, "de-tuning" was just a form of reducing the venturi size of the carburetion. Kinda like in the 9.9's and 15's of the later era.:cool:
 

seahorse5

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Re: Why did OMC like the number 8?

I think the later 20hp is just an 18 with a slightly larger carb, isn't it? The carb on the 20 was 379032 and on the 18, it was 278402.

the 18 and 20hp motors have a funny history. OMC had the 18hp since 1957 and in the '60's Johnson bumped it up to a 20 at the time by using a higher lift reed stop and carb work. Ralph Evinrude was the head of OMC at the time and he insisted that the 18 remain in the Evinrude line-up as it was so well known over the years. So there was an Evinrude 18 and a Johnson 20 for several years.
 

1946Zephyr

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Re: Why did OMC like the number 8?

the 18 and 20hp motors have a funny history. OMC had the 18hp since 1957 and in the '60's Johnson bumped it up to a 20 at the time by using a higher lift reed stop and carb work. Ralph Evinrude was the head of OMC at the time and he insisted that the 18 remain in the Evinrude line-up as it was so well known over the years. So there was an Evinrude 18 and a Johnson 20 for several years.

Yep, I figured it had to be in the reeds and carb. I find that the 18's and 20's ran together, from 1966 - 1973. In 1974, both were discontinued in favor of the smaller 15's and the (still yet 22 cubes) 25 continued on till 1976. This marked the end of the classic split case lower unit, which was started in 1949 on the old Johnson QD-10 and 1950, on the Evinrude Fastwin 14hp.
In 1977, the classic 22 cube design was dropped entirely and the 25 was redesigned as a lower rpm 31.8 cube.
 

Joe Reeves

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Re: Why did OMC like the number 8?

And all along I thought it was just a mathematical racist thing they had against numbers 7 and 9. :)
 

Dhadley

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Re: Why did OMC like the number 8?

They were the first Dale Jr fans.......
 

montff77

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Re: Why did OMC like the number 8?

EDIT: Hijacking a thread is a no-no, montff, particularly if it is an old, dead thread.
 
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kfa4303

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Re: Why did OMC like the number 8?

I believe they did a similar sort of thing with some of the big twins too. I had a '66 33 hp, which always seemed like an odd hp rating to me, but I think it was really a "detuned"/budget 35 hp. It didn't have a thermostat or a couple other little things, but it was electric start and overall a pretty awesome, super strong motor.
 

JB

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Re: Why did OMC like the number 8?

Old thread, kfa.
 
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