This page is dedicated to my classic British
Seagull outboard motor, a Silver Century Plus Fixed Drive, Serial
Number SP1718D8, which I purchased new on 23 June 1968. It
still looks excellent, as you can see from the pictures below. And
still runs as the first day!
With the sole exception of the rubber tie-down on
the tiller arm for the throttle cable (replaced with two black
tie-wraps), and the fuel valve repair procedure detailed below, this
motor has never required any major disassembly or repairs. It is
still the same motor I received when new, except for normal wear, as I
have replaced a few parts with new, original replacements when it has
become necessary. Yes, most parts are still available new or used
from a number of sources.
After some four years of use with a custom-made
15-foot marine plywood dinghy, I lay it down for some 25 years.
These were the years of my graduate studies abroad, and of the return to
my country to establish my independent practice as a clinical
In 1998, I took my Seagull out of storage, gave it
some tender, loving care, replaced the high tension coil cable and plug
cap, the throttle cable, put in a new Champion D-16 spark plug (I
decided to keep in storage the few original Champion 8-COM spark plugs I
still have), repaired the fuel valve, cleaned and calibrated (gap of
0.50 mm/0.020" for both the points and spark plug) the contact breaker
points and spark plug, and put in some fresh SAE 140 oil in the gear
case (I replenish the oil after getting the water out which has entered
the gear case, approximately after every 15 hours of use). Works
like a charm since then.
In 2000, I got a 4.9 m/16' in length aluminum
which I use with my Seagull for fishing in
dams, lakes, rivers, and, yes, quite daringly, in open waters of the
Caribbean Sea when it is calm and the wind is down. The Seagull
has always been a faithful, reliable, trustworthy, and, in all frankness
and fairness, a very noisy and smoky companion.
Typical fishing outing is some 8-10 hours running
at one-half to three-fourths full throttle, only stopping to refuel.
Of course, I continue to use the recommended fuel mixture in the
proportion of 1 part of outboard oil into 10 parts of regular gasoline
Needless to say, I always carry some spares, like
new spark plugs, propeller springs and retainers (washers and split
pins), as well as several hand tools, including a gap calibrator.
And, following the owner's manual, I always secure my engine (and all
gear aboard) with a lanyard.
My Seagull has always brought me and mine back to
port, regardless of rain, wind, or how rough the sea has gotten.
And I trust it will do the same for my children, when they become of
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A Scary Tale
This past Saturday was a scary day, for I went
fishing with a friend in my little aluminum tin can, a 16-foot (4.9 m)
Crestliner JRMV 1648. As usual and expected, no fish. We were in
very deep waters, outside of the Bay of Salinas, in the southwestern
shore of the Dominican Republic, way beyond the designed capabilities of
the boat, but doing well. My pal, an experienced skin diver, was
already seasick, after eating something that did not agree to his
stomach. Then, an unexpected, and most severe, gust of wind went through
all the area, raising the waves to the point of nearly capsizing the
boat. Actually, there was a moment when I thought that the wind would
lift out of the ocean and overturn the boat, which I think did not occur
because of all the added weight of the water already inside the boat.
Within a couple of minutes or less
after this gust of wind started, we were half-full of
water, and the engine--a 1968 vintage British Seagull 5
HP outboard--stopped because water grounded the spark
plug, and my efforts to get help via my hand-held marine
radio got no reply. Actually, before the engine stopped
I could not do any steering with it, as the wind and the
current were so strong that we were at the mercy--or
wrath--of the waves. My pal was very seasick and was of
no help. Actually, I think that he was ready to
"surrender his papers", for he afterwards told me that
he then felt so lousy that sinking felt like a welcomed
alternative to the way he was feeling....
The wind subsided as quickly as it
came, and the waves gradually stopped coming inside the
boat. I decided to bail out as much water as I could
(with a 16 oz/475 ml Styrofoam cup), to improve our
floatability. My friend sort of woke up when he started
feeling the hardness of the bottom of the boat, as he
had been suspended in part by the water inside. After I
got most of the water out, I got to work on the engine
and eventually got it going, but only after quite a bit
of work. I even had to put some gas inside the cylinder
chamber, as I think some water got inside the
carburetor. Of course, I had some extra spark plugs,
and had to replace them twice, as the water inside the
motor quickly dirtied them.
Eventually, the motor ran,
sputtering for a minute or so, and then flawlessly, as
We had been thrown out to sea some 3-5 miles (5-8 Km).
Luckily, the deep blue waters were quite navigable, with
2-4 feet (0.6-1.2 m) waves, and we were able to make it
to shore. However, upon entering the bay again, the
waves were about 4-6 feet (1.2-1.8 m) high, very much
the limit of the boat, but with some skill and prudence,
we were able to make it safely back to port.
This was the first and, hopefully, the only time in some
40 years of going to sea that I felt that I was nearly
losing a boat from under my feet. My thought was that I
was going to lose the boat, and that somehow I would
have to return swimming, but when I saw all we had to
travel to get back to shore, the thought dawned on me
that I may not have had the energy to have made it back
swimming, as the shore was too far away. At that time,
it was also clear to me that my friend would have lost
his life at sea if we had gone under.
Certainly, an event to be written in the Book of
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The Fuel-Oil Mixture
The controversy is an interesting
one, particularly when faced with environmental issues.
Unfortunately, these issues were not considered as
pressing ones at the time of the development and
manufacture of the British Seagull. Rather, longevity
and reliability of the engine were far more important
attributes. At least, that is my impression, and
definitively the reason why I am the proud owner of one
The manufacturer was very specific
as to certain minimum conditions required for the
Seagull, the theory being that little was required for
it to work reliably, as long as those few rules were not
In particular, the oil to gas
ratio of "one-part of oil to ten parts of petrol" as the
"MINIMUM", the "DON'T REMOVE" the cylinder head, and the
importance of the spark plug as the first suspect in any
difficulty when starting or running the engine. And, of
always secure your engine with a lanyard".
Deciding to use "1 IN 10" as
opposed to "1 TO 10" would only slightly enrich the
proportion of oil to gas in the mixture, and
theoretically protect even further the internals of the
engine, while producing more smoke from the unburned oil
(and we all know they produce a lot of smoke and noise,
anyhow). This is consistent with the manufacturer's
recommendations, as stated in the engine owner's
manuals, in quotation marks above.
The case in point with further
reducing the amount of oil in the fuel mixture, e.g.,
1:25, is that while better protecting the environment,
one would have to do serious laboratory research to test
the hypothesis that the new synthetic oils adequately
protect metal parts conceived, designed, and machined
for the 1:10 fuel mixture.
I do not know of any empirical
research done in this area. What I do know is that new
Seagulls are no longer being built, and that many of the
internal parts of these engines are no longer
manufactured or not replaceable. So, I wonder, why put
these engines at risk?
Of course, the British Seagull
will eventually become, for its quality and reliability,
a distinguished museum piece, as it belongs to an
industrialist era disrespectful of the environment.
Meanwhile, I will try to use mine sparingly, but the way
it was conceived by its engineer designers to be run:
"one-part of oil to ten parts of petrol" as the
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Fuel Valve Repair
The bottom row of pictures below shows a fuel
valve repair procedure that I have developed. If you do use this
technique, I would appreciate hearing your comments about your
experience with it.
What I have done with my old brass fuel tap is to
replace the damaged cork seal with four, same-size "O" rings (in my
case, automotive type, nothing special), OD 3/8" (0.375" or 9.525 mm) x
ID 3/16" (0.1875" or 4.7625 mm) x Section 3/32" (0.09375" or 2.38125
mm), that is, of the appropriate size to produce sealing friction.
This seems to be a permanent repair, as these "O" rings withstand
contact with fuel, and are quite resistant to friction by movement.
I initially performed this repair as a temporary solution, but this was
several years ago, and the valve is still maintaining friction at the
plunger, thus it is working fine.
Actually, inspection after some eight years of use
showed, as can be seen in the pictures below, some wear of the two "O"
rings furthest into the fuel valve. However, the valve was still
shutting off the fuel effectively. I just replaced the "O" rings
with a new set of the same type and size. Upon installing the new
"O" rings I noticed that the fuel holes in the valve produce a small
nick on the "O" ring furthest into the valve, although this does not
seem to affect performance, as the two orifices for the fuel inside the
valve are offset.
Further, repairing the fuel valve can be completed easily. All
that is required is to drain all fuel by loosening the fuel hose from
either end, and opening the valve by pulling on the plunger, if still
operating. Then, remove the tap from the valve by loosening the
retaining screw on the side of the valve. The valve body does not
have to be removed from the fuel tank. Just carefully cut away the
cork, after removing the plunger from the valve body, and fit in the set
of four "O" rings.
A bit of engine oil helps to push the "O" rings in place, but do not use
any sharp tools in the process, as this will cause damage to the "O"
rings. The "O" rings are kept in position by the plunger and by
the body of the tap, and they produce a very effective seal.
One other repair technique I have
read about, but not used, is to boil the tap with the
dried-up cork in order to revitalize it. Actually,
I read about this after I had improvised with the "O"
rings, so I did not try it. I am surprised that
the original manufacturers of the fuel tap were using
cork for this purpose, as it is a material that degrades
easily. Particularly since "O" rings have been
around for quite a while.
Two special fuel-related situations: fuel is
flowing out from the carburetor side, or when tilting the engine.
The first is typical Seagull behavior, as this occurs after flooding the
fuel chamber in the carburetor with the special plunger on a cold start.
As soon as the engine is started, this overflow stops. If not,
then you should suspect that there is dirt in the fuel chamber, or that
there is a problem with the fuel needle or float.
As to the second situation, the Seagull manual recommends to use up the
fuel in the carburetor fuel chamber when reaching port by closing the
tap and letting the fuel burn prior to tilting the engine, or else it
will spill out. Do remember not to tilt the engine past the
I want to remind Seagullers of a tip oft repeated in the Seagull manuals
and oft forgotten: secure your engine with a lanyard. This is
often overlooked and the cause of many lost engines overboard.
Hope this helps.
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I remember having had a problem with my engine
rocking on the support. In my case, the problem was not related
directly to the support bracket, but to the tilt mechanism. I
described this problem to a Seagull parts retailer at the time
(Sailorman) as follows:
"I have noticed the engine support lug rocks a bit on the mounting
bracket, even with the security bar in place. Does it use some
gasket to reduce the space (about 3 mm) between the support and the
bracket to prevent this lateral, and perpendicular axis movement?
Inspecting the parts, I did not notice any adjustment possible, nor did
I notice this rocking movement when the engine was new. The new
engine support lug I installed is some 3 mm wider than the original
part, but still leaves a gap of about 3
mm. Both parts of the main frame member (alloy and bronze) seem to
be in mint condition."
I could not get any specific answer as to why this was occurring.
I remember that Bryan A. Nelmes, the Sailorman tech at the time, told me
he even contacted the factory on this problem, but no results. I
solved the problem by adding an appropriate-size "O" ring to one side of
the support lug, held in place by the security bar. This was
several years ago and it is still fine.
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Pictures of My British
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