" I have a 1986 GM 350 Volvo-Penta I/O. The recommended timing setting is 8 deg BTDC at idle. If I set the timing at 8 deg it idles VERY rough, hard to keep running. If I set it to about 20 deg BTDC it purrs like a kitten and runs great on the water.
Its a new boat to me and I upgraded from the old points ignition, and I had never checked the timing with the old points system so I don't know where it was to start with.
What bothers me is, is running so far out of spec dangerous to the engine and why is it this way? All I can figure is the pulley has moved, a sheared key or whatever causing the mark to be in the wrong position.
My idea it to "Power Tune" the boat i.e. run it on the water at cruise speed and adjust the timing to get the max RPMs and not worry about where the marks are. Some friends said this was a good idea, others said a bad one. Looking for opinions/suggestions.