Replace Rectifier in 1965 Merc

[vampirefish]

Hello all. Well, I'm almost to the point of troubleshooting my charging system. I'm guessing I will have to replace the rectifier. If I do, I have a couple questions for the experts! I have a 1965 Merc 900E Short Shaft O/B, 90hp, Inline 6. <br /><br />Looks like I have 3 differents routes I can take here:<br /><br />1) There's a rectifier on sale for a merc on this site: http://www.iboats.com/mall/index.cg...ectify&**********=320290981&*******=765397606 - Would this work? I googled this and see that it works with 'All applications with square, 3 post rectifier'. I'm not sure what type I have..but here's the part (ref #7): http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=%2038612&ivar=images/MERMAR/38612/11.png&inbr=394&bnbr=7&bdesc=STARTER+MOTOR%2C+STARTER+SOLENOID%2C+RECTIFIER+AND+WIRING+HARN ES<br /><br />2) I've heard (from this site) that one can go into Radio Shack and buy a $3 Full-Wave Bridge Rectifier: <br /> http://www.radioshack.com/search.as...ier&site=search&SRC=1&image1.x=34&image1.y=43 <br />I never have much luck with the 'help' at the shack, so of course when I mentioned it to the sales guy there, that it would be for a boat, he poo poo'd that idea...so I'm not sure which to buy.<br /><br />3) Don't do anything (not an option)<br /><br />I'm guessing it may be better to just buy one from this site (if it will work)? Any suggestions would be mucho appreciated!<br /><br />THANKS IN ADVANCE

 

[vampirefish]

Re: Replace Rectifier in 1965 Merc

Any advice on this would be greatly appreciated!

 

[Laddies]

Re: Replace Rectifier in 1965 Merc

As a Marine Mechanic I would only use Oem or the eqivalant part for liablity reasons, so I couldn't advise you any differantly, I see a lot of stuff that works that is hardly proper or in a workman like matter that owners and freinds do to marine engines to save money. I guess I don't blame them, their just trying to save money, but when sh!t goes bad I don't want to be the one responsable--Bob

 

[vampirefish]

Re: Replace Rectifier in 1965 Merc

Thanks, Laddies -- I tend to agree. Do you think this will work:<br />http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=%2038612&ivar=images/MERMAR/38612/11.png&inbr=394&bnbr=7&bdesc=STARTER+MOTOR%2C+STARTER+SOLENOID%2C+RECTIFIER+AND+WIRING+HARN ES

 

[JasonJ]

Re: Replace Rectifier in 1965 Merc

I am one of the "hethens" who uses the 'shack Bridge rectifier. Guess what, a rectifier is a rectifier. There is no difference between it and those super spiffy "marine" applications as far as function goes. It is epoxy sealed, it is cheap, and it works. You can spend big loot if you want, but I have used the cheapies for years with no bad results. I do mount them on aluminum heatsinks so they last. I have never had one fail, even if I disconnect the battery while the motor is running, which is a big no-no because it pops those superior marine expensive rectifiers. Do what you want, its your cash..

 

[69GlassparMan]

Re: Replace Rectifier in 1965 Merc

I need to replace mine as well. I see the radio shack one is a component small recifyer. What one did you use Jason? How did you install it<br />thanks buddy.<br />I will be at Hayden lake in July, Maybe I can drop by and introduce myself with my boat!<br />tod

 

[Laddies]

Re: Replace Rectifier in 1965 Merc

Jason, if you burn yourself and family up up no one cares, if you are a marine shop and burn up some one else the laywers will love you. As a marine mechanic I wouldn't want to put someone else in that position, there is a big differnce in what one does on their own stuff and that is done for hire--Bob

 

[vampirefish]

Re: Replace Rectifier in 1965 Merc

Laddies, do you think this rectifier would work with my 1966 Merc? It says it works with 'All applications with square, 3 post rectifier'. <br /> http://www.iboats.com/mall/index.cg...172406&search_type=keyword&keywords=rectifier <br /><br />I'm not sure what type I have..but here's the part (ref #7): <br />http://www.mercruiserparts.com/Show_Pictures3.asp?dnbr=%2038612&ivar=images/MERMAR/38612/11.png&inbr=394&bnbr=7&bdesc=STARTER+MOTOR%2C+STARTER+SOLENOID%2C+RECTIFIER+AND+WIRING+HARN ES<br /><br />thanks!

 

[Laddies]

Re: Replace Rectifier in 1965 Merc

The 18-5707 will work fine, you might have to drill a couple of holes to mount it--Bob

 

[vampirefish]

Re: Replace Rectifier in 1965 Merc

SWEET - That's what I'm going to go with then. THANKS SO MUCH!!!

 

[JasonJ]

Re: Replace Rectifier in 1965 Merc

Laddies, lets ease up on the drama. I know they teach gloom and doom in wrench school, but you have to know that I know better. I am well versed in what works and what does not work, and a simple diode that clips the alternating current to give direct current mounted to an oversized piece of aluminum via heat conducting grease is not going to explode or burn up. At the very worst, it would just pop, not unlike what happens with the oem part. As I said before, a rectifier is a rectifier, not much can be said to make a person think otherwise. I would not expect a shop to do such a thing, a shop should use the proper part, that is what the customer is paying for. A do-it-yourselfer has to do what they have to do sometimes. <br /><br />BTW Vampire, thats a cool little Tahiti. I rebuilt the Mercuiser 470 in a 1980 17 ft Tahiti last year. Yeah, the 470 isn't a fantastic inboard, but that 175 ponies in a boat that weighed nothing was pretty impressive. That thing definately peeled the eyelids back when I was done with it, pretty sweet. The owner promptly sold it and went out and bought a big **** package Tige wakeboard/ski boat that is just crazy. Got a good deal on it for $30somthingthousand, must have been nice...

 

[timmathis]

Re: Replace Rectifier in 1965 Merc

It is like the old saying YOU CAN LEAD A HORSE TO WATER BUT YOU CAN'T MAKE HIM DRINK.

 

[JasonJ]

Re: Replace Rectifier in 1965 Merc

Tim, it has nothing to do with bullheadedness or stubbornness. It is Laddies's job to make sure people do things that do not damage their equipment or cause injury, and to make money. My point was that I am no novice, and I know what is safe and what is not safe to do, so I don't appreciate disproportionate drama. That is how people in the service industry make money, they create a sense of emergency where there is none just to panic people into spending money they don't need to. It is not ethically sound. I know, I am in the service industry, and refuse to blow things out or proportion just to turn a buck. That is my point. I think this has run its course, time to fish...

 

[vampirefish]

Re: Replace Rectifier in 1965 Merc

UPDATE: I got the rectifier from iboats<br /> http://www.iboats.com/mall/index.cg...172406&search_type=keyword&keywords=rectifier <br /><br />Here's my question....it's a 3 post and my old one (still connected) appears to be a 4?? ...how do I hook this puppy up? There are some other wires connected right now to my old one.... Just don't want to ruin anything.<br /><br />I do know that I'll need some heat sink compound... (from reading through this forum)..<br /><br />thanks!

 

[JasonJ]

Re: Replace Rectifier in 1965 Merc

I am fairly sure that 4th post was a ground wire. The 3 post would ground to the block through the housing. Check the wires on the current rectifier, one probably goes to ground. Laddies can confirm, since he knows his stuff.

 

[Laddies]

Re: Replace Rectifier in 1965 Merc

You have should have 2 yellow wires that come from the alternator and 1 red that goes on the + termanal, I have never seen a ground wire but anything is possible after a few years, someone may have installed a grd. you never know. Just make sure that the red is on the + termanal and the yellows are on the other 2, in some cases there is a signal wire for the tach on with one of the yellows for a alternator driven tach. If this don't explain it enough try to expain to us were the forth wire is attached--Bob