September 25, 2020 at 10:46 am #217254
I am in the process of trying to restore my father in law’s old Martin 40 outboard motor which probably hasn’t run in 50 years. It has been stored in the back of our garage for years. It’s in decent shape and is not seized up. So far, I was able to get it to spark by cleaning the points and changing out the spark plugs. I’ve removed the carburetor, separated the float bowl, and soaked in gas for a couple days. I then fabricated a gasket and reassembled the motor. After adding fresh gear lube and gas/oil, I was able to get it running. It runs at high speed, but I can’t seem to get it to keep running at lower speeds. When I move the control lever past the mid (Start) position, it seems to starve for gas and stops. Does anyone have any suggestions?
Also, I did replace the water pump rotor. However, I’m not sure how well the motor is pumping enough water to cool it down. It is spitting out water out of the two ports mid way up the stem (motor support tube), but I was expecting to see a steady stream of water. Does anyone know whether this is normal for this motor or tell how to determine if the motor is being getting sufficient cooling?
Topics: 48September 25, 2020 at 11:55 am #217260
The thin brass tube going down through the center of the carb from the top is the idle tube. All of the idle fuel comes up through that tube, which has very small passages which get clogged easily. So make sure it is squeaky clean. Also, the slow speed mixture needle on that carb works backward from what you would normally expect. Screwing it “in” makes it richer.
US Member - 2 Years
Topics: 47September 25, 2020 at 2:11 pm #217264
Be careful when taking the carb apart. IIRC, you should remove the high speed needle before you separate the carb top and bottom, or you can bend the high speed needle.
The low speed jet should be removed and cleaned, as noted above. Do not scratch or deform this tube. If there is a gasket on its flange, make sure the gasket goes back in. Also, remove the plug in the top of the carb and clean out the area where the idle tube goes. These areas are typically plugged up with old fuel.
Spitting out of the hole in the rear of the leg is typical. You will not see a steady stream.
TSeptember 26, 2020 at 2:20 pm #217332
Thanks all for your replies. I will remove the carburetor again and clean per your suggestions. I will post an update after I run the motor again.October 24, 2020 at 7:20 pm #219248
An update on my progress in restoring my Martin 40. I thoroughly cleaned the carburetor, replaced gaskets and packing. The motor is running better and I was getting it dialed in when the starter rope broke. Is there a trick to replacing the starter rope? Is there a clip for attaching the rope? I tried using a knot, but I can’t clamp down the starter housing on top of the knot. I did not pay attention to how it was installed before the rope broke.
In case anyone is interested, I attached a file that I made while working on the carburetor that you might find useful. I couldn’t find a good spec sheet on this carburetor, so I decided to make one.
You must be logged in to access attached files.October 24, 2020 at 10:19 pm #219264
You're only as smart as the person you're talking to.October 25, 2020 at 11:52 am #219292
Is the pin that you are referring to in your first photo item 106 of the Starter Cover and Assembly drawing? If yes, do I need to punch out the pin in order to place the end of the rope with the melted glob behind it inside the pulley?
You must be logged in to access attached files.October 26, 2020 at 9:29 am #219354
You're only as smart as the person you're talking to.October 27, 2020 at 11:22 am #219420
Thanks for the information. I was able to replace the starter rope as you suggested without having to disassemble the starter housing. I might not have made the melted glob big enough and will give it a try later today. If the rope does not stay in place, I can might try using a bigger melted glob, and/or crimp a stainless steel hog ring next to the glob to keep it from sliding thru the rivet.
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