"J.J.... Your question is bein
"J.J.... Your question is being listed under a topic pertaining to a 1960 20hp Mercury. If you're reading this, when you're done, hit your back button to the previous page that lists all of the member topics. Page down to the bottom of that page and you'll see a large button there that states "Create New Conversation" (something of that nature). Click on that button and your message will be entered under your own topic and at the top of the list. You did contact me via e-mail also, which I answered so I will enter a duplicate of my answer here for others who might obtain some benefit of my reply.
To set the timing on that 1987 115hp Evinrude, with the s/plugs out, and with the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary). Rig a spark tester and have the spark gap set to 7/16". Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4° less that what the engine calls for. In your case, the engine calls for 28° so set the timing at 24°. The reasoning for the 4° difference is that when the engine is actually running, due to the nature of the solid state ignition componets, the engine gains the extra 4°.
If you set the engine to its true setting (28°) at cranking speed, when running it will advance to 32° which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place.
No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting.
You have some doubt as to what engine you have.
The 120 and 140 are "Loop Charged" engines which incorporate four (4) single throat plastic like carburetors that are contained (hidden) within a huge carburetor face plate. The 115 is a "Cross Flow" engine that has two (2) metal dual throat carbs that are in plain sight with a moderate sized face plate attached to the front of the carbs.
Your engine has a plate on the port transom bracket or on the top of the swivel bracket that contains the model and serial numbers of the engine. The model number reveals the horsepower and year. There is also a core plug on the powerhead (looks like a quarter size freeze out plug) that also has those numbers. Get that "Model Number" to me and I'll pinpoint exactly what you have.
Joe (30+ Years With OMC)"
