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Aidan Smith.
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October 17, 2026 at 3:14 pm #330182
Hello all…
Picking up a Martin 40 in the next couple of days here, that is supposedly not locked up. I believe it has been stored inside, but am looking for some information on these. Never worked on one before, as I understand, it has a poppet valve instead of reeds, among other many differences.
Any help on where to start would be great. I’ve already found a good manual online for it from SoCal AOMCI.
Thank you,
Aidan
1952 Blue Streak "B-Stock Runabout" - 1952 Mercury KG7Q
1955 Feather Craft Vagabond - 1956 Mercury Mark 55EOctober 17, 2026 at 7:21 pm #330193The intake valves are not what we call poppet valves, they are in fact positive acting , cam operated valves. This a unique feature on Martin outboards. I believe that the earlier models had metal seat surfaces on the valves, later model had a rubber “o” ring.
Joe B
1 user thanked author for this post.
October 19, 2026 at 2:58 pm #330264Well,
I’ve learned something new. Very interesting on the whole aspect of them. Anything that is known to break often?
1952 Blue Streak "B-Stock Runabout" - 1952 Mercury KG7Q
1955 Feather Craft Vagabond - 1956 Mercury Mark 55EOctober 20, 2026 at 10:05 am #330318The condensers are probaly shot. They run about $15.00 each plus around $15.00 postage and handling. I’ve found a way to install capacitors in them. Much, much cheaper.
October 20, 2026 at 10:33 am #330321
These pictures are from a 75. In case you don’t get this deep into yours, levers in the block run on eccentrics on the crank that operate the valves. My son-in-law uses this motor for fishing and running around the lake. In 6 years there have been 2 issues. After 4 years the original cork gasket for the cover on the head, that seals the water jacket, began leaking. Last year the crank shaft broke but I’m sure that is a rare occurrence, if not to only time that has ever happened, and it still ran to get him home. Fixed it and he used it this summer without any issues. This motor gets run a lot and aside from the broken crank, its been very reliable.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.
October 22, 2026 at 8:56 pm #330426I seem to recall opening the carb needle valve LEANS the mixture (lets in more air, not fuel)
http://www.omc-boats.org
http://www.aerocraft-boats.orgOctober 23, 2026 at 10:55 am #330446Got the motor, and its in quite nice condition. Someone has added a rope sheave over the years, which I am not sure is an original Martin accessory option. It has great compression, and is really clean. No spark though.
1952 Blue Streak "B-Stock Runabout" - 1952 Mercury KG7Q
1955 Feather Craft Vagabond - 1956 Mercury Mark 55E -
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