Flyingscott, Thank you. I'm adept mechanically, however I wasn't about to try to sync up 4 carburetors. I'm glad you reminded me that it idles on 2 cylinders - overall an ingenious design. Oil injection plus an all-mechanical approach to switching from 2 cylinders to 4 cylinders at about 2,000 rpm makes for a very reliable engine. So far, knock on wood, it has been very durable. I only use it to go 3 miles out on Lake Michigan to start trolling (using a kicker motor), then coming back in 3 miles. Each round trip is about 30 minutes, thus 20 trips maximum per year is only 10 hours of use each summer, plus a few spins around the lake with the grandkids and I may put on 10-12 hours per year. Great engine.
I do have an online manual, and it specifies that there is no traditional idle speed adjustment. Rather, adjusting the idle speed (as you say, when the engine is at normal operating temperature and under load, thus in gear) is accomplished by adjusting the idle speed ignition timing vis-a-vis the stop screw on the long bracket that terminates under the flywheel. The adjusting screw on the bracket causes the bracket to slightly retard the timing, thus slowing the engine. I wish I could take a photo to show you. My plan is to lower the boat while in its hoist, start the engine and allow it to completely warm up, put it in gear at idle speed (it can't go anywhere in the hoist), then adjust the bracket stop screw slightly to see if and how it affects the idle speed.
Your thoughts?
It may be my imagination but it seems the "clunking" when going from neutral to forward, has become more pronounced, thus I'm trying to reduce the idle speed to decrease the clunking and presumably reducing the gear wear.
