Thanks again for the pointers. I found the following in the FAQ on the
Edson Web Site:
Q4: My throttle doesn''t hold when I push it full forward - what can I do?
A4: Some Engine have a very tight spring on the throttle lever. Depending on the Engine Control Model, you may be able to tighten the Throttle Friction Adjuster. Older controls may not have this adjuster, but a "horseshoe" cable-clamp can easily and inexpensively be clamped around the outer jacket of the engine control cable to add the proper cable resistance.
http://www.edsonmarine.com/faq/index.html