90 HP mercury 2 stroke not charging

[Mrnecks]

I have a 1994 90 hp mercury that isn't charging. I checked the stator last night per the manual and it reads .4 ohms. I'm not sure i understand the manual if this is correct. I also noticed a burnt looking spot in my voltage regulator, pretty sure that shouldn't be there but I'm just trying to confirm which part to replace. Any help is appreciated.

 

[delta229]

Re: 90 HP mercury 2 stroke not charging

I would bet that its the regulator. If the Stator tested good and the face of it and the rotor are clean and free of rust, it is a safe bet to say that it's good. The Stator is a very basic electrical device. A hot spot, burnt spot or melted spot on the regulator indicates that an internal component has failed or is overheating. If you do replace the regulator put some thought into how much load you have on it. Have you overloaded it or do you have some wiring issues. I would spend some time just cleaning connections and looking the wiring over before I started the motor with the new regulator.

 

[MrMikeTN]

Re: 90 HP mercury 2 stroke not charging

Its worth the $26 to put a new regulator rectifier and test.
I bought 2 of them for my 1986 Merc 90hp Inline 6. Only takes 10 minutes to change it, it'll take more time getting the cowl, front palte and the motor cover off then it will to replace it.

BUT make sure you NEVER NEVER NEVER NEVER ever never hook the battery cables up backwards or let the ground pop out of your hand and hit the POSITIVE post or vise versa for even a MILLISECOND.. Because you probably just blew that rectifier!! And who knows what else!!
And right after I changed the Rectifier I would ease out onto the lake and run a few DVA multimeter tests, Because the rectifier might be whats blowing, but you might have a different componet like a Switchbox, stator, trigger or something else thats causing the rectifier to blow.
I just went thru the whole chasing my tail around and around the motor untill I fixed my Electrical problem.

 

[Mrnecks]

Re: 90 HP mercury 2 stroke not charging

I ordered a new one and will give it a try when it shows up. It was more in the 60 dollar range though. Thanks for the Help!

 

[Texasmark]

Re: 90 HP mercury 2 stroke not charging

If you are using a digital multimeter, you need to zero your leads and add that number to what you read in the circuit under test. My DMM measures 0.4 ohms lead resistance on the lowest ohm scale (200 for mine) with the leads touching . If I were running your test with my meter and got the reading you got I would conclude that that the stator was shorted.

For the red 16 amp stator used on the 90 engine, between the two yellow stator leads the resistance shall be 0.16 to 0.19 which has to be added to your zero'd number. The reading varies as a function of temperature being hight with hight temps. Either yellow stator lead to engine block (ground) should be an open circuit on a higher resistance range, like 1k or more.

The burnt spot on your regulator is probably your smoking gun. You should only see epoxy potting, black as I recall on the face of the rect/regl.

Mark

 

[Mrnecks]

Re: 90 HP mercury 2 stroke not charging

My DMM is the same, 200 is the lowest setting. So you think both reg and stator are bad?

 

[Mrnecks]

Re: 90 HP mercury 2 stroke not charging

 

[Barnacle_Bill]

Re: 90 HP mercury 2 stroke not charging

Your stator is good. Replace that burn't rectifier/regulator.