70 hp merc stator ohm specs

[russellackland]

I have a 1979 3cyl 70HP mecrury outboard. The battery is not charging. The voltage output at the main wire (with no battery connected) is about 6-8V at idle decreasing to near zero as the RPMs increase. The same reading comes straight from the Voltage Regulator "red Terminal." I checked the two yellow wires to the stator (disconnected from VR) and I get continuety ( 0 ohms). The engine still runs without the battery, so some power is coming from another system in the stator I guess. There must be separate charging sytems for the battery and the power pack? Does the entire stator have to be replaced? What is the spec reading for the ohm meter supposed to be for the battery charging part of the stator?

 

[hltenterprises]

Re: 70 hp merc stator ohm specs

Russell<br />Try this website<br /><br /> http://outboardparts.com/mercury/miscellaneous/troubleshootinghelp.htm

 

[petryshyn]

Re: 70 hp merc stator ohm specs

russellackland<br /><br />Stator spec is .74 ohm<br />(don't forget to take your lead resistance into account)<br />You need an accurate meter for this test.....<br /><br />Because of the voltage dropping off when rpm goes up, I suspect you should have the battery hooked up when testing with your exact meter. With the battery connected, see if the voltage climbs when engine rpm is up to 2000 or so. Best to take it for a run while monitoring the voltage for a few minutes. If no rise, do a rectifier test. If rectifier tests OK, check the a/c voltage at the rectifier while running. This will check the stator.<br /><br />Remove these 2 leads from the rectifier and check the a/c voltage. It should be 15v or higher.....

 

[russellackland]

Re: 70 hp merc stator ohm specs

That is a great picture! and that is exactly what I have (except I removed the grey tach wire). I was using a digital automotive type ohmmeter, and it only goes to the tenths in ohms. Still it indicated 0.0 ohms.<br /> At idle, I checked the AC volts on one yellow wire, getting 1.0V and the other wire was 0.0V. It will be a couple weeks before I get to the lake again to check it some more.

 

[petryshyn]

Re: 70 hp merc stator ohm specs

you must connect your meter across both stator leads at the same time to take this a/c voltage reading..... remember, leaving the leads connected to a possible shorted rectifier may skew readings.....disconnect them before testing

 

[russellackland]

Re: 70 hp merc stator ohm specs

finally got to lake,<br /><br /> the AC volt readings are 30V @ idle and up to 90V at 3000 rpm. There is Zero volts at the red lead of the VR (with a load connected and no battery). I am guessing that hte VR needs replacing. I got a 1.1 ohm reading from the stator.<br /><br />thanks for the help.<br /><br />russell