mercury ignition questions

[mrmarvc]

Hi again,<br />I haven't been on here for a while as have been so busy. I have a 1966 Mercury 650 65 hp that I have been doing things to get it back up to par. Mostly done except the distributor. Put in new points and condenser, but need to know if anyone can tell me what the gap should be set at. Also, the motor accidently got cranked over just a touch with the distributor off the motor. Will I have to realign everything to have the timing and stuff right? If so, can I just get #1 cyl. to top dead center of compression stroke and point rotor to #1 on dist cap? On the toothed shaft of dist that slips into motor there is one spot that is sort of flat like it will go in only one way, is this right? I can turn the dist shaft by hand and there seems to be a very good spark that bites my hand pretty good, so I think the dist is good. Also do any of you know about condensors, when they go bad, are they dead. I thought on a condenser, they are either good or bad, no inbetween like good till they are warm then act up, is this true? Better stop here, as I have dumped a lot of questions on you and may be a little overwhelming. Thanks, Marv.

 

[petryshyn]

Re: mercury ignition questions

The mag can be taken off the engine a couple of ways. Did you remove the belt and sprocket? If not, the mag will only go on the appropriate way to mesh the missing tooth.<br /><br />>Point gap .008-.010<br /><br />>Capacitors can fail intermittently or abruptly. There are several tests for a capacitor. Capacity, series resistance and leakage. The best tests require a special meter. Likely you don't have one. If you don't do the above tests, the capacitor condition is un-determinable. Since most capacitors fail "internally shorted" you can play the odds and check a capacitor with an ohmmeter, looking for shorts from case to lead. Again......this is not definite in its condition. The condition of the points (how they are wearing) also give hints to the capacitors condition. <br />If you don't have access to all of these special tools, simply replace the capacitor.<br /><br />>With regards to the magneto, were you missing spark?<br />>Were you missing spark at all cylinders?<br />>Did you inspect the caps and rotor carefully?<br /><br />The coil can give up as well....

 

[mrmarvc]

Re: mercury ignition questions

Thanks schematic for your reply.<br />The points seemed to be wearing pretty good, except in one tiny spot where there was just a very small pit on one side and a very small peak on the other side. I can spin the dist by hand and touch the copper contact with one finger and the housing with another and get a pretty good bite from it with no condensor installed. Will go ahead and replace it anyway, along with a new cap and rotor. Also, can you tell me if automotive plug wires will work on here, or do they need to be the kind with multi-strand wire in the center? Thanks for your help, the dist is only thing left fo put together and put back on for the big trial of seeing it run.

 

[petryshyn]

Re: mercury ignition questions

If you have pits and peaks on the points, replace the capacitor. Getting a shock from the mag can be a long way off from enough voltage to jump the plug, so it doesn't mean much.<br />Automotive high tension ignition wire comes in variety of styles. There are metal core wires available for industrial engines. The problem you might run into is the end connectors. It may be more feasible to get a new OEM wire if required. I'm not one for the "replace all" approach. Are you sure you need a cap, rotor, wire etc.? It might be worth your while to get a marine shop to look at these components first....<br />Parts are expensive and usually non-returnable...

 

[tmcalavy]

Re: mercury ignition questions

replace the points and capacitors, clean the rotor/cap contacts. the dist. shaft is notched to go back on only one way, so you're good there. when I am rebuilding the ignition on antique outboards with magneto ignitions, i replace the plug wires/boots with solid core wire I get from my local mower/ small engine shop. Just an idea. Oh yeah, the Seloc manual for you merc comes up quite often on ebay....get one, its a good investment if you plan on doing your own maintenance/repairs.