Martin 75 Twist Shift

[davidk]

I’m looking for guidance on how the twist shift is supposed to work.  Does turning to the right move it to neutral?  Turning to the left releases it into gear?  What it the button on the end meant to do?  Also, what it a good starting position for the main metering screw (T screw) below the carb?  Thanks for any input.

[Tubs]

Two parts as just 2 links makes everything go poof.  Clockwise is neutral. Moving the magneto lever from slow, it will stop at 12 o’clock when its in neutral. The button on the end of the tiller controls the carburetor butterfly. You can control the speed of the motor without having to turn around. I find it most helpful when crossing a large wake. Video link – https://youtu.be/7_2ipgNUf-k You should also investigate the transom clamp option. Begin with the main jet out about 3/4 turn out.  Same with the low speed.  Low speed is air, not fuel. I find that the low speed adjustment changes from cold starting to when it’s warmed up, so I have modified mine so it’s easily adjustable.

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

1 user thanked author for this post.

davidk

[Tubs]

 Here is a link to an issue with mine last summer you might find interesting. https://www.aomci.org/forums/topic/1952-martin-75-twist-shift-rod-knocking/    The only negative thing I can say about this motor is some exhaust comes up the clutch cable tube. This brings up a bit of water, and oil, if the boot is missing. The oil makes a mess as much as this one gets run. Russ has an update kit I installed this winter. I made a small modification to it and it seems to be the answer.

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

[Tubs]

 

Clockwise is neutral. Moving the magneto lever from slow, it will stop at 12 o’clock when its in neutral. The button on the end of the tiller controls the carburetor butterfly. You can control the speed of the motor without having to turn around. I find it most helpful when crossing a large wake. Video link – https://youtu.be/7_2ipgNUf-k  You should also investigate the transom clamp option. Begin with the main jet out about 3/4 turn out.  Same with the low speed.  Low speed is air, not fuel. I find that the low speed adjustment changes from cold starting to when it’s warmed up, so I have modified this one so it’s easily adjustable. Here is a link to an issue with mine last summer you might find interesting. https://www.aomci.org/forums/topic/1952-martin-75-twist-shift-rod-knocking/    The only negative thing I can say about this motor is some exhaust comes up the clutch cable tube. This brings up a bit of water and oil if the boot is missing. The oil makes a mess as much as this one gets run. Russ has an update kit I installed this winter. I made a small modification to it and it seems to be the answer.

 

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

[davidk]

Thanks for the response, Tubs.  Very helpful, as usual.  I had this out on the lake this past weekend and it turned into a clusterfrig.  I thought the twist handle on the tiller would increase speed if I turned it clockwise.  I was surprised to find it drop into gear as I twisted counterclockwise.  I noticed the spark advance would stop halfway when I was in neutral (now that I know it was neutral).  The engine repeatedly stalled when I lowered the spark advance.  Lot’s of urgent fiddling with the high speed needle.  It was ugly.  I’m eager to try again, alone this time, to spare my wife from suffering my loss of composure and grace.

What do you mean about investigating the transom clamp option?

I’ll investigate the cable boot upgrade.

[Aidan Smith]

Bring it to Saco… I’m sure Lincoln will have a thing or two to say about it.

"Shells sink, dreams float. Life's good on our boat."
1949 Mercury KE-4
1952 Mercury KF-3,-5,-7
1952 Mercury KG-7Q

1937 Evinrude Scout
1938 Elto Pal
1946 Evinrude Ranger

[Tubs]

Check the carb float bowl and see what’s in there.  I would suspect the stalling in neutral is likely the slow speed mixture setting.  Try adjusting the slow speed mixture screw, in neutral, with the mag. advanced all the way against the stop. Mixture screw in for a lean backfire as it’s an air adjustment. If a backfire kills the motor, I need to choke mine. It will start and die, then with the choke back off, it restarts in 2 or 3 pulls. When I get mine adjusted where it runs well when its warm, its off about a ¼ turn when I go to start it when it’s a cold.  Tilt the motor forward and look for this pin.  Lift it and move it to its other position. Now you’ll be able to spin the motor into the boat to remove fishing line, change the shear pin, or just to get people around you wondering how did he do that!!!  

 

 

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

1 user thanked author for this post.

davidk

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