1985 140hp Johnson tach not working sometimes

Today I ran my 140 Johnson and recently the charging system/tach was not working but thats been happening for the last 4 fishing trips. When I shut the engine off a drifted for awhile I soon had to start the engine because I was getting to close to shore. Before starting the engine I turned the battery switch to #2 it had previously been on #1. The engine started had now the charging system/tach was working. Shut the engine off to drift again and upon start up on #2 now the charging system/tach was not working. Does this help in the diagnosis of where to look for my charging system/tach not working. I can assume that the rectifier diodes are ok. Can I eleminate stator or the powerpact? If I clean the connections which connections should I clean? Thanks

Re: 1985 140hp Johnson tach not working sometimes

Intermitent problem such as what you describe can really be tough to solve.<br /><br />Diodes in a rectifier do not become intermitent. They are either good or bad, and if bad, they stay that way. However, if you have a water cooled voltage regulator/rectifier on that engine (and I'm pretty sure you do), to contradict myself, that unit could be intermitent.<br /><br />I know that sounds confusing but there are rectifiers that are simply that... rectifiers which aren't regulated, and there are the "Water Cooled" regulator/rectifiers.<br /><br />First, find the electrical terminal block at the engine and check for loose and/or tight but dirty connections. If that cures the problem, fine. If not......<br /><br />If the engine has a water cooled regulator/rectifier unit, find the gray wire that leads FROM the engine's wiring harness to the terminal block. It is not doubt connected to another gray wire that leads to the regulator unit.<br /><br />Move that harness gray wire from it's terminal and connect it to the yellow/gray wire that leads to the stator. If no yellow/gray wire but rather two yellow wires, try one yellow wire then the other yellow wire.... it may work on either.<br /><br />If the tach now operates as it should (constantly) but does not when the two gray wires are hooked together, consider the regulator/rectifer assy to be faulty and replace it.<br /><br />If the tach still is intermitent regardless of the above, consider the tach to be faulty.