Reply To: 1973 6Hp Evinrude Fisherman hard starting cold

[Tom Bertulli]

Wow, What brain trust here. There is almost too much to answer at one time but I’ll try to address each of you.

To John Holbik. I Know how you feel but i’m sure most of us here have as much fun trying to fix this old stuff as we do running them. It brings me back the 50’s & 60’s when my dad could fix anything with just a library book. Spent a lot of time in the basement with him. What he couldn’t afford, he made. He wound his own A/C welder in the late 30’s. The guys in the electrical shop near us gave him scrapped transformers for the iron core and scrounged magnet wire for him. We had that welder in the garage until he bought the “Miller” in 1970.

Cosbyman & Billw I cleaned the rubber line and ports on the side of the block with carb cleaner, wire and compressed air. I did not see any dirt but the motor now starts in 2 pulls cold at just over 1/2 throttle. I’m reading throttle position from the cam under the mag plate, because Fleetwin is right- those handle markings are always suspect. I’ve Cut back the LS needle to just over 2 turns, the motor idles down just a bit slower and is still smooth.

Fleetwin, There is no linkage binding the mag plate- full range of motion is smooth and without major slack. Starting position is read on the throttle cam. Good point about the flywheel / key geometry. A small change at the flywheel centre produces a large change at the flywheel edge – can’t believe I missed such a simple concept. Part of the issue with this motor was the excessive slack in the mag plate bearing (which I shimmed out using a piece of .005 brass shim stock). No matter how well I set the points, they would always end up way off after 10 minutes of running. Have you checked for slack in yours which would throw the point setting off during use? I can’t think of anything more to advise you on. I have more thinking to do on this concept of OMC timing. Please school me here anyone.

1 When measured against the index marks on the mag plate ( and assuming points properly set) A timing light will show the spark firing in the same spot REGARDLESS OF THE THROTTLE HANDLE POSITION. yes or no?

2 Spark timing at the plug is governed by the movement of the mag plate because it’s movement changes the relationship between the when the points close and when the piston reaches top
dead centre. Yes or no? Or is my thinking completely screwed?

3 As engine speed increases, is the spark timing is advanced or retarded? For example as the mag plate moves to the right and engine speed increases, is the timing advancing or retarding? Should be advancing – correct?

Thanks all