'70 40hp ESL-70a Magneto Wiring

[dmgroh]

I'm doing this from a 40 year memory, and I'm pretty sure it is correct, but no spark. <br /><br />This setup is exactly like the '50s & '60s I have tuned up when I was a teenager. 2 coils, 2 points, 2 condensers. The coils have 2 small (18 gauge) wires; one off the top of the coil is a ground and the other opposite that ground coming off the bottom of the coil goes to the points (correct?). Double checked the plug wires & point gap, everything that grounds is grounding, no shorts, etc.<br /><br />Is there a way to check the coils?-they look good visually, and there are no shorts (that I can find). Is there a way to check the condensers?<br /><br />This is such a simple system and I'm scratching my head! What have I missed? <br /><br />Is there

 

[JB]

Re: '70 40hp ESL-70a Magneto Wiring

How about the history, dmgroh?<br /><br />Has it ever run for you? How long ago?<br /><br />Except for any kill circuit (you don't mention one) that is two, independent magnetos. Really unusual for both to fail at the same time.

 

[OBJ]

Re: '70 40hp ESL-70a Magneto Wiring

DM....did you disconnect the harness lead and hand pull the engine? Problem might lie in the key switch. There is also a vac switch on the side of the engine (port side) you can disconnect. If there is a shorting harness on the engine, that also could be disconnected to rule out the shorting switch.<br /><br />You can test the condensers with an ohm meter. Put the meter leads across the condenser. Meter should rise and then fall to "0" ohms. If the meter stays up, bad condenser. You can also ohms check the coils. Can't remember off the top of my head what they should read. I'll take a look when I get to the shop.<br /><br />EDIT: Took a replacement coil and read through the primary winding, very low ohms...less than 1. Secondary (spark plug lead) very high. But JB is correct in saying that for both coils to go out at the same time is unlikely. As posted, isolation of the system should lead you to the culprit.

 

[dmgroh]

Re: '70 40hp ESL-70a Magneto Wiring

Thanks for the help... I am rebuilding this from a bucket of parts(history died with the owner). I never installed the vacuum cut-out or any other wiring...wanted to see spark before I got too far along. Just a simple magneto, and checked all wires for abrasion, continuity, shorts. I agree that both would likely not go out at the same time. Everything has been isolated to just the condenser, coil and points (which are new).

 

[Paul Moir]

Re: '70 40hp ESL-70a Magneto Wiring

You should have a pair of wires that lead down from the magneto plate, one from each point terminal. These are used for shutting down the engine as well as for the vacuum cutout switch. If you just want to test for spark, these wires should be isolated from each other and ground (taped off).<br /><br />Most common failure in the igntion system is cracked insulation on the ignition coils. They almost never fail internally. If the points are cleaned and gapped correctly, and the coils are healthy it should fire. You do have the crankshaft key in place for the flywheel right?

 

[dmgroh]

Re: '70 40hp ESL-70a Magneto Wiring

Thanks again for all the great advice. Problem was (at least) one of the coils. It looked like almost new, but insulation was flaking off. Other coil gave erratic ohm numbers; especially while I was moving it around during the test to check for just such a problem. <br /><br />Anyway, I've decided to dump the magneto and go with battery ingnition, I need a 12v battery anyway for both the electic starter (no recoil on this motor) and the electric gear clutch.

 

[Paul Moir]

Re: '70 40hp ESL-70a Magneto Wiring

The magneto is cheap and easy to fix. It is also far more reliable than any battery system. Why not just fix it? The modern coils are superior to the old ones, especially the aftermarket coils (18-5181).<br /><br />The biggest problem you're going to run into if you try to convert it to battery is to get the points to work backwards. On magnetos, they spark when the points open while battery systems spark when they close. The cam isn't going to accomadate you.

 

[CATransplant]

Re: '70 40hp ESL-70a Magneto Wiring

There's really no need to to to battery ignition. As long as you have the flywheel off, just replace those coils. The aftermarket coils are very reliable, at least the Sierra Marine ones are.<br /><br />Here's why: Even though you don't have a recoil starter on that motor, you can still rope start it in an emergency. If your battery's dead, you'll want that, and batteries go dead from time to time, for various reasons.<br /><br />That old magneto system is reliable as can be, especially with a fresh pair of coils installed. While you're at it, replace the points and condensers too. You'll be set for another 35 years of reliable service.<br /><br />That's my advice, for whatever it's worth.

 

[dmgroh]

Re: '70 40hp ESL-70a Magneto Wiring

Thanks! You talked me out of it! I can spend a few hours searching for those coils, but can your experience point (no pun intended) me to the best place to purchase those coils?

 

[Paul Moir]

Re: '70 40hp ESL-70a Magneto Wiring

I'm obliged to recommend our hosts, Iboats. They've got a good price on them. Locally, if you're located in the US, you can get them at NAPA autoparts. That's the aftermarket P/N I gave you so you'll find it all over the place. The dealer P/N is 584477.<br />If you're outside the US, please tell us where you are so we can help you find an exporting supplier.<br /><br /> http://www.boatmotors.com/mall/part...gd_poid.109172/gd_row.1/**********.756267476/