Re: 1990 Merc outboard 115 piston replacement
CharlieB I owe ya a beer! Though I had previously tried grounding the sparks and had negative results, your post encouraged me to try it a different way. I made a contraption to screw the plugs into and ground them so they would fire outside of the block. After doing that my timing/switchbox issues seemed to have disappeared. I made some timing adjustments and fired up my new engine. I think all is well!! I had it on the water last night with great success.
An interesting thing about the timing is that the "max timing (while cranking) was way the hell off. Off the scale to advanced. That is assuming I'm not doing something wrong. If I'm not than this could be the reason for the previous piston damage. As far as I can tell it is now limited at 20deg BTDC.
Only thing I have to deal with immediately is the warning/buzzer system. It buzzes when IGN is turned on but never stops buzzing after the engine starts. As far as I understand an intermediate buzz is for low oil, contstant buzz is for over temp. The temp gauge doesn't appear to work either but that is a separate temp sensor altogether. I will test the warning temp sensor/switch later but I'm curious as to what signals the warn module to stop beeping after the engine starts. I guess it would have to be increase in voltage or is it supposed to stop after a few seconds of IGN being on? In fact I don't get what the module even does being that the temp switch is connected both to the module but also the buzzer directly and its other input (low oil float switch) is also a simple switch.
Well the boat floats and runs and despite the expense of the new powerhead I'm a happy camper.
CharlieB I owe ya a beer! Though I had previously tried grounding the sparks and had negative results, your post encouraged me to try it a different way. I made a contraption to screw the plugs into and ground them so they would fire outside of the block. After doing that my timing/switchbox issues seemed to have disappeared. I made some timing adjustments and fired up my new engine. I think all is well!! I had it on the water last night with great success.
An interesting thing about the timing is that the "max timing (while cranking) was way the hell off. Off the scale to advanced. That is assuming I'm not doing something wrong. If I'm not than this could be the reason for the previous piston damage. As far as I can tell it is now limited at 20deg BTDC.
Only thing I have to deal with immediately is the warning/buzzer system. It buzzes when IGN is turned on but never stops buzzing after the engine starts. As far as I understand an intermediate buzz is for low oil, contstant buzz is for over temp. The temp gauge doesn't appear to work either but that is a separate temp sensor altogether. I will test the warning temp sensor/switch later but I'm curious as to what signals the warn module to stop beeping after the engine starts. I guess it would have to be increase in voltage or is it supposed to stop after a few seconds of IGN being on? In fact I don't get what the module even does being that the temp switch is connected both to the module but also the buzzer directly and its other input (low oil float switch) is also a simple switch.
Well the boat floats and runs and despite the expense of the new powerhead I'm a happy camper.