EVER SEEN 9 20H's IN A ROW??
I HAVE 2 OF THESE!
You thought I was kidding about all those restored
B Mercs? Well, here's photographic proof that they exist. And there's
a thumper and one more totally original one not in the photo. Look
close at these, this is NOT a trick photo. Some have short skegs,
some long. Some have steering bar bolts, some don't. These thumbnails
are links to bigger scans, so click your mouse on 'em to see the
For those of you who haven't a clue, this motor
was developed by Mercury in 1954 as a replacement for the KG-7H
"Hurricane", as the competition was fierce in class "B" racing, and
they were getting beat! It has a similar cranktrain to the Mark
25 service model introduced in 1955. However it used unique components
for most of the powerhead parts, not shared with the MK25. Originally
equipped with a Carter model "N" carburetor.
Champion motors developed a racing "B" called
the "B hot rod" that soon eclipsed the 20H, so Mercury engineering
got busy and developed a revision to this motor titled "new carburetor
and accessories". The "accessories" consisted of a new fully tuned
exhaust. This noisy item soon earned the nickname of "thumper".
This motor just died out with age, as the parts sources dried up,
and race sites banned the noisy critters. The motors seen here are
mostly "de-converted" with this tuner removed. Several are originals
though. This model is very collectible right now, as all those old
dudes (like me!) that raced 'em are wishin' they had'a saved one
There has been a renaissance of the old "B"
class runabouts using these 20H motors as well as the other contemporary
models of the 50's. Under APBA rules, boats and motors must comply
with the rules then in effect.
CREDIT must go to Charlie
Williams of Performax Marine in Puyallup,
WA for spending the time and effort to restore all these to as close
to original as possible. He can be contacted at OUTBOARDRACING.COM.
The rules for "Classic B" may be found there as well.
FUN WITH OLD RACE MOTORS
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