old style rectifier help

[ChrisD2725]

Ive got a 1965 90hp tower of power that i suspect has a bad rectifier. With the engine running, im getting 101 volts ac at the output terminal and the tach pegs as soon as the engine starts. Additionaly i have continuity from the output side to the ground side and it looks to have been arching between the ground side and the engine shroud.

Im almost convinced it is bad but as far as i can tell the diodes test ok. So what gives? And what is a suitable replacement for the long discontinued oem part?

 

[sam am I]

How old style? Like this old?

Did Merc make a 90HP in 1965? Perhaps 50HP or 65HP?

Or it's an 850XS from 1976'ish with a tach max at 6K?

 

[flyingscott]

Yes mercury made a 1965 90 hp merc are you checking the correct outputs. 100 volts ac sounds right for the ignition side seems high for the charging side. Do you have a manual fort the motor.101 volts ac to the battery would be BAD.

 

[ChrisD2725]

http://m.ebay.com/itm/272182439185 one of these.

 

[sam am I]

Well for crap sac's, I only see 500M, S and E, 650S and E manu'd in 1965....hmmm, google, go figure!!

Yes, any of the more present day rectifiers rated for your stator/system/enviro such as this one, will work fine.

or

this if you want to add different connectors and save $$$. Runs at 50 Amps with 600V reverse voltage at 150 degrees C. Probably better rated and run forever as compared to the smoke and mirror things that are over priced (and conveniently have no real electrical spec's) we see all too often.

 

[GA_Boater]

When I had a local Radio Shack, which is now closed blue, I picked one of these to replace the original rectifier and it is still working great after 5 years - https://www.radioshack.com/products/50v-bridge-rectifier?variant=5717581317

 

[sam am I]

Lil low on the PIV GA, some can be up @ approx 200VAC @ 5K+ but, 5 yrs ain't nothing to sneeze at....:thumb:

 

[GA_Boater]

It works better than the original selenium rectifier - This one works!

I only got a 6A stator - So that's 400 % margin. I'm safe on the PIV, too. If I wasn't, I would have grabbed a $6 rectifier. LOL

 

[sam am I]

No doubt.........and amazing savings too!! Cheap meter even went full scale