1975 50HP Evinrude, no spark. Sensor coil?

[KeithLuneau]

My dad just picked up a 1975 50 HP Evinrude (50573B). It's got no spark on either cylinder. I started checking things, kill wire is working, not always grounded. Stator seems to check good. The sensor coil is always open, infinite resistance between the two wires, and from each wire to ground. That doesn't sound right to me. Could that make it stop firing on both cylinders?

I just want to have a better idea of what I'm looking at before I start dropping money on parts. Someone said he thought it might need a power pack since both cylinders stopped firing. Is it possible to check the power pack before replacing the sensor coil, if it is in fact bad?

Thanks in advance!

 

[KeithLuneau]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Anyone?

To rephrase and shorten my question...

If the pickup under the flywheel (timer base?) is reading always open with an ohm meter, does that mean it's bad and needs to be replaced? Will that make the engine stop firing on both cylinders? Is there a way to test the power pack if that pickup is bad?

 

[KeithLuneau]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Thanks for all the help!

 

[EN2]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Open circuit would indicate that it is bad.

 

[KeithLuneau]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Thanks for your reply. I was starting to think that there wouldn't be one...

I've ordered the timer base assembly, it should ship out Monday. I'll let you know if that cures it!

 

[KeithLuneau]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

How about a LOOONG overdue reply?

So we bought that new timer base, it came in, checked just like the old one, open circuit. I thought maybe my meter was being weird or something, asked a couple of local shops, both of them told me the sensor coil can't be checked with an ohm meter on this engine. That goes against everything I know, but then again I'm no outboard mechanic, and I have seen stranger things than that... lol So trusting their advice, I put the new sensor on, still no spark. I sent it back for a refund. I went to another shop that had supposedly worked on this engine before my dad got it. That guy said he remembered it well, and that the coil pack was bad when he looked at it. So I ordered a coil pack. Put that on, still no spark!

So, I started loosing faith in these local shops, and started trusting my own judgement again. I ordered a new sensor coil from another web store, which came in today. This one tested 18.4 ohms, that's more like it! I put it on the motor, and both plugs give a nice big fat blue spark now. So I put it all back together, mixed up a gallon of gas, and the engine fired right up, runs great!

I haven't checked the oil in the leg yet, so we just ran it a few minutes to see if it was going to pump water, and if it would even run at all. It seems fine.

So now I just need to check/change the oil in the leg and get the boat in the water and try it out.

(Any idea where to look to find out how to check that oil? No search terms I've tried seem to bring it up. I'm guessing there will be a plug somewhere, and oil level is to the bottom of that hole like on most other things, but I don't want to make assumptions and ruin a good motor.)

Anyway, thanks for the help! I'll be sure to ask here next time instead of asking the few local "mechanics" around here...

 

[EN2]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Click on T.D "S TOP SECRET FILES.Scroll to Changing Lower Unit oil.

 

[jay_merrill]

Re: 1975 50HP Evinrude, no spark. Sensor coil?

Pretty simple. Look for two stainless screws in the gearbox with heads that are about a half inch across. They will have straight slot type screw heads. The bottom one is the drain/fill point and the top is a vent.

When you drain the oil, be sure to open the top screw too, so that the gearcase drains completely. Drain the oil into a pan so that you can feel the oil with your fingers to see if there are any signs of grit or metal in it. Also look at the oil for color - if it has a milky appearance, you are getting water in the oil.

If you have no obvious problems, fill from the bottom until gear oil starts coming out the vent hole. Reinsert the vent screw, tighten and then unscrew the oil fill fitting and reinsert the drain/fill plug. The vacuum created by the vent being closed will prevent you from losing too much gear oil as you do this.

When doing the job, be sure to buy new crush washers for the drain/fill screw and the vent screw. Replace the old washers, as they are intended for one time use. This is very important, because the screws are the most common point for water intrusion. Of course, be sure to use the correct gear lube for your engine. If your motor calls for "Type C" gear oil, use BRP "Premium Blend," which is the current equivalent.



???