TOPIC: Choke control for Merc Mk. 55A

Well, I'm new to the forum and I'm off and running with a restoration of a 1964 Evinrude Sport 16. It currently has a 1959 Mercury Mark 55A which I think was just thrown on the boat to help talk someone into towing it away.

I plan to get the Merc running (as long as it doesn't call for a teardown) and then sell it, using the money as part payment for a 70-90 horse motor with electric start. I've done my time pulling on starter ropes and my rebuilt shoulder will never pull another one.

My question is this. I've made a new rod that connects the two carb chokes, as the old one was broken. But - what actuates the chokes?



Is there a missing solenoid? The engine controls (which I found lying on the floorboard) have a SPST switch, but no choke lever like on my old 19' Johnson with the 140 Chev I/O. I assume the switch may be for choke activation, but I see no mechanism on the motor for this.

I also need to replace a return sping on one of the starter dogs. I sure hope the whole starter assembly doesn't need to be disassembled for this!

Any words from the wise would be appreciated.

the choke rod runs up thru a hole in the top cowl with a choke rod knob for manual operation

for auto choke...bolted up inside the top cowl is a solenoid in which a piston plunger will retract to close the chokes

the piston attaches to the choke rod assembly by a cable , rotate the piston around facing up into the solenoid once the top cowl is on

your going to need that "choke rod assembly with piston" , assuming the solenoid is still in the top cowl

choke wire from solenoid to internal wiring harness is blue

That confirms my suspicion that it could be an electrically operated choke. There is no solenoid or choke piston evident. I don't believe there is a hole in the top cowl for a rod and knob, but that would be the easiest solution - especially since I will be selling the motor.

I won't just drill a hole in the cowl if it's not there. I think this motor is in pretty good shape for an unrestored example of the marque. Just think - it was manufactured only a year after I graduated from high school!

I'll have to take another look at the top cowl to be sure there isn't something like a hole and grommet in it. Do you happen to have a picture showing the manual choke knob?

By the way - the only wiring evident on the motor is a short wire coming off the magneto. I assume this is the wire which, if grounded, kills the mag. Except as mentioned below, there is no "wiring harness" for the motor. It has no electric starter, alternator or rectifier.

There were two wires, a red and a black, taped to the throttle/shift cables. They terminate inside the throttle quadrant and, I'll bet, connect to the SPST switch which is sticking through the side of the throttle housing. Those may be for the choke. They were all grungy, so I untaped and tossed them.

Thanks for the info!

if you have no wiring then it sounds like a manual start motor and there wont be a choke solenoid

can be be upgraded to electric start for about $100-150 in parts

Oh, it is a manual start. Aside from the missing starter motor, the flywheel is not toothed for a starter.

As soon as it warms up a few more degrees, I'm going to bundle up and walk out to the boat to see if there is a hole in the top cowl for a choke pushrod and knob. The Climate Change is setting new record low temperatures here in the Puget Sound region.