Topic: 1953 Firestone 10 hp, Model 1835, Lower units

This topic has 9 replies, 4 voices, and was last updated 1 year, 10 months ago by Tubs.

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June 28, 2023 at 10:40 pm #277561
Buccaneer
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Got this “half” a motor with a mass purchase back in 2016, and it’s
been on the rack ever since, as it’s missing the gear case and driveshaft.
I never even had the cowls off before, but it did turn over.
I wasn’t too optimistic, it must have been in a garage sale at one time……
it had “FREE” wrote on it in a few places!

Decided to take a peek at it today. Feels like great compression.
Just for kicks I thought I’d squirt some fogging oil in it to see
if there was any signs of life.
Looks promising, no if I only had the rest of the motor!

I presume the gear case from a 10 horse Scott of the same era would fit,
but not sure if any other HP motor’s gear case would.
Anyone know?

From what I’ve found online, I “think” it is / was a non-bailer outboard.

There’s four studs coming out of the lower unit leg, 3″ apart, front to back.
Not sure about the width. I looked at my 1956 Scott 7.5 hp lower units,
and it’s totally different.

VIDEO
https://youtu.be/nPdUUzJiTFM

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June 29, 2023 at 7:09 am #277566
Tom
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I’m pretty sure the lower unit is identical to the 10 hp Scott Pennant. It’s NOT the same as the 7.5 of that era. It is not a bailer, there is a single 6-vane impeller just above the anti-cav plate. With a little work, a Honda impeller will work, but you need a sleeve to reduce the ID of the pump housing and maybe take a little off the top of the existing cup so the top plate seals. These are pretty nice engines, but louder than similar motors of that era. The “straight leg” Scott was dropped within a few years for the Bail-A-Matic motor with the curved leg and the high mounted cooling and bailing pumps. WICO condensers will need to be replaced, almost a guarantee. And never tilt them up by pressing down on the tiller handle.

T
June 29, 2023 at 8:47 am #277568
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Tom, thanks for the information. Unless I come across a cheap parts motor,
there’s too much missing to buy the parts “piece-meal”.
Maybe I’ll bring it to Tomahawk to see if I can swap it for something.
A 10 hp is just the right size for my little Alumacraft though…. hmmm.

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June 29, 2023 at 9:57 am #277570
Tom
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I ran one for years on a Lone Star Lil Fisherman, it was just right for that boat. Three tries on a photo, I give up.

T
June 29, 2023 at 1:42 pm #277582
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I checked the compression on the Firestone 10 hp this morning.
71 & 73 psi. Not sure what “new” was, but it would be a runner for sure.
Popped the flywheel off, and while the Wico coils are cracked all up,
the did fire the engine on fogging oil.
Pounded some dents out of the cowlings, put it all back together,
hung a tag on it with my findings, and back on the rack for now!

I haven’t had much trouble lately attaching photos from my harddrive.
Here’s one from yesterday for a test. of the Oliver, now awaiting
on the boat for a ride….. but it’s getting too windy… maybe tomorrow.
The Oliver “green” almost matches the color of my rusty old Cheverolet truck!

UPDATE: the photo posted, but the flipping thing went sideways, lol

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June 29, 2023 at 5:40 pm #277597
retiredoz
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Pre-’54, the first year of the BOM units, Scott had three full-shift lower units : The 5 and 7.5 shared one, the 10 had its own, as did the 16. Nothing different about the badge motors like Firestone or Corsair. You just need a pre-’54 ten-hp lower unit, nothing else will fit.
June 29, 2023 at 6:14 pm #277599
Tubs
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A "Boathouse Repair" is one that done without having tools or the skills to do it properly.
June 29, 2023 at 6:15 pm #277600
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retiredoz wrote:

Pre-’54, the first year of the BOM units, Scott had three full-shift lower units : The 5 and 7.5 shared one, the 10 had its own, as did the 16. Nothing different about the badge motors like Firestone or Corsair. You just need a pre-’54 ten-hp lower unit, nothing else will fit.

Good to know, thanks!

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June 29, 2023 at 6:16 pm #277601
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Tubs, must have been some “Black Magic” to get that Oliver up-righted!

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June 29, 2023 at 6:25 pm #277602
Tubs
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Dynamite – 2 sticks
.

A "Boathouse Repair" is one that done without having tools or the skills to do it properly.
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