No fire at the plug when trying to start 100hp evinrude

[heyitswebb]

I have a 100 hp evinrude 1972, I swap this motor from one boat to another, it was running fine before, now it won't start, Everthing appears to be fine, I feel it is someone im just overlooking or hooked up wrong when putting on the boat. I know that the rectifier is bad, one wire the black is burnt out, but it was running before I swapped it out. I'm totally lost on what to do, no mechanic near here. Also the rectifier is not available for my model, part # is 510885. Napa does not list one for a 1972 100hp and I cant find it listed on any parts list on the web. has writing on it p 268 varo r315. would part #582399 or 583408 work in it place it looks just like it. Help me, thanks Tim

 

[Joe Reeves]

Re: No fire at the plug when trying to start 100hp evinrude

The number you list of 510885 is not a OMC part number. If you're getting that number off of the rectifier, it's simply a casting number.<br /><br />The correct rectifier for the 1972 100 hp Evinrude is OMC part number 583408. (582339 superceeds up to 583408).<br /><br />You can check the powerpack as follows. If you need one (pack), I have a new left in my remaining stock which I will discount.<br /><br />(Battery Capacitance Dischage Powerpack Test)<br />Various OMC Engines - 1968 to 1972)<br /><br />Purchase a small 12v bulb at your local automotive parts store (the 12v bulb is to look like a flashlight bulb, not a headlight bulb). Solder two wires to that bulb, one to the side of the bulb (ground), and the other to the positive point. <br /><br />Remove the spark plugs. With the key in the on position, make sure that you have 12v going to the pack at the terminal block (purple wire). Now, connect the ground wire from the bulb to any powerhead ground. Connect the wire from the positive point of that bulb to the powerpack wire that is connected to the coil wire on the terminal board (blue wire). <br /><br />Crank the engine and observe that bulb closely (CLOSELY!). If that bulb glows even the slightest bit, the powerpack is okay. It may be a very dim glow... just so it glows! If it doesn't glow, the pack has failed. <br /><br />Keep in mind, that type powerpack (Battery Capacitance Discharge) demands a top notch battery of at least 70 amp hours. Any less will, in time, cause powerpack failure.

 

[heyitswebb]

Re: No fire at the plug when trying to start 100hp evinrude

Thanks Joe, but will the rectifier being burnt up now cause me to have an electrical problem trying to start? Thanks for the right number on the reictifier i'll pick up the new one on tuesday.

 

[Joe Reeves]

Re: No fire at the plug when trying to start 100hp evinrude

The only purpose of the rectifier is to convert AC voltage that is being emitted from the stator to DC voltage in order to charge the battery. It has nothing to do with the ignition system other than keeping the battery charged so that proper voltage is available to the various components.<br /><br />If you had no rectifier, but the battery was a top notch battery which was fully charged, and everything else was as it should be, you would have ignition.<br /><br />Caution.... Check the voltage at the terminal block where the RED wire of the rectifier will be attached. It must be 12 volts positive (+). The rectifier will not tolerate reverse polarity even for a fraction of a second.

 

[ajp]

Re: No fire at the plug when trying to start 100hp evinrude

Joe, <br /><br />What causes the packs to fail so often on these older units. Do you have a pack for a 74 Rude 115hp. #115493-B<br /><br />arlan@pldi.net

 

[Joe Reeves]

Re: No fire at the plug when trying to start 100hp evinrude

AJP.... The usual cause of powerpack failure if it's a case of the powerpack failing on the same engine frequently is that the ignition switch is shorting out ever so slightly to the black/yellow wire ("M" Terminal on the back of the ignition switch).<br /><br />That black/yellow wire leads directly to the powerpack kill circuit and it will not tolerate any voltage. That problem can be tested easily with a volt meter set to its lowest reading. With the key in the ON position, if even a fraction of a volt reads on that black/yellow "M" terminal, replace the ignition switch.<br /><br />I do have a few of those powerpacks on the shelf. ReevesJ32@aol.com