Rectifier or Stator-'03 Mercury 90 hp Stroke

[TrenchFisherman]

I know this has been gone over but I think I have narrowed it down but before I go over to my boat today I wanted to get a final opinion of what could be wrong. I was out the other day and when I went to start my boat it cranked a few times then stopped. I figured I left something on and that is why so I went and jumped it and drove around for about 45 mins and anchored up for a while and when I went to start it again I got a few cranks and then died again. So i though for sure my battery was bad so I brought it home and charged it overnight til 100% on the gauge and took it over for a load test and the guy said it was fine. So now I was like great so let me take it over and put it on the boat and do a voltage check while running. Well it read about 12.7 with the motor off and with the motor running about 12.9volts. I am assuming its either the rectifier or stator going bad and I hope its the rectifier because my tach is bad as well. I was going to go over and do the yellow grey lead to the grey lead on the tach trick like it says in the FAQ section but what else should I be looking for other than a melted stator?

 

[gm280]

First of all if you're reading a higher voltage with the engine running, then the charging circuit isn't gone. It could be suspect, but not gone. You can check the AC out of the stator on the yellow wires with it running to see what voltage is there. Or even disconnect the yellow wires on the rectifier and read resistance and make sure it isn't shorted to ground. If it reads in range, and not grounded, the stator is good. You can also verify the rectifier by the forward reverse readings. If any of them shorted or open, then replace the rectifier. There is one other possibility for low voltage from the stator. You could have a magnet missing on the flywheel...

 

[NYBo]

Start with clean, tight connections at both ends of the motor cables.

 

[TrenchFisherman]

i checked the stator and that was within spec and it turns out that it is the rectifier. After looking it over I noticed that there was a blow out in the gel type material. I also gave the wrong information as the voltage drops about 0.2 volts when the engine is running compared to when it is off. The new rectifier is on it's way today so I am excited to get it on there!