Evinrude 25253r ignition points questions

[webbrs]

Which is the coil that is for #1 cylinder, front or back in relation to the carb? Also the manual says the "flat retainer 'must' be horizontal in relation to the armature plate." The spring of both sets of points is too long for this. Do I have them in wrong or do I have to grind the spring down? I can put the clip on from the top but don't know if that's ok.
Plus a bit confused about my coil test readings. The coils I removed had impedance of 6900 and the new OMC coils both test at 44 and 4500. Product support sent me a link that said anything from 3000 to 8000 is a good coil. I would think the lower resistance would make for better conductivity. but I also think that the higher resistance would create a more powerful spark by creating a delay in the release. Maybe I have it wrong, I'm not a mecho/electrical engineer.

 

[flyingscott]

You should not need to grind anything to put them on you need to put them on from the top. When you put the points in on the post the spring needs to be set so it pushes the points closed. When you put the part with the spring down on the post make sure the spring goes inside the aluminum stop. Then slide the retainer in from the top to hold the spring in place. I don't know why you need to know which coil is #1 but you can follow the spark plug wire back to the right coil. If I remember right the retainers have an indentation in them that matches up with the hole in the aluminum post.

 

[oldboat1]

Here is a good instr. on coil testing: http://www.penn.itgo.com/video-pages/coil-testing.html

Back coil should fire the top cylinder*** (have me rethinking it now -- points and condenser on the right for top cylinder). Plug and play if you have the right points. Maybe a pic somewhere on Leeroy's site: http://www.leeroysramblings.com/index.html

[ed. ***nope. Front coil, top cylinder. See F_R's post, below.]

 

[webbrs]

One would need to know if there were no ignition on the powerhead when it was bought. Or if one took it all apart without noting where stuff was....
​Anyway thanks for the info. Testing wasn't a problem just the readout was in question.

 

[flyingscott]

Coils will fail one of 2 ways 99% of the time they either crack and the humidity gets them. The other way is they fail when they get warm which is why I don't like coil tests because people seldom test the at temp and heat raises resistance. That is why there is such a wide range for testing.

 

[F_R]

My 2 cents: That little copper clip is supposed to slide in from the side (horizontal). Reason is, if vertical it may interfere with the points arm opening all the way. But if no interference, no problem with it being vertical. Why does the spring extend out too far? Answer: Crappy parts we get nowadays.

As for the coil's secondary resistance, what produces the available spark voltage is largely due to the turns ratio between the primary and secondary windings. However, there is nothing written in stone as to the diameter or length of the wire. Therefor, the resistance may (and does) vary from mfr to mfr. Or even within the same mfr. I just look for several k-ohms and let it go at that.

Finally, the coil nearest the front of the motor (carb end) is the TOP cylinder.


photo uploading

 

[racerone]

As usual Frank is correct !!

 

[kbait]

Go to 1st page of this forum, click on 'top secret files', then click universal magneto troubleshooting and read up. Tons of info!

 

[flyingscott]

I have a question I have had the problem he has with the springs being long usually shows up more on after market points. The problem I had was the spring was long and over time actually pushed the clip off and was rattling around under the flywheel. How do you fix that.

 

[oldboat1]

Thanks, Frank, for the correction and the pics.

 

[webbrs]

Bad thing is that these are OMC points. I get outsourcing tho, probably still made in china. Nope scratch that I just read made in Turkey. The spring is much too long to go at it from the front, no way it would reach the retainer. Hope it doesn't come off that could be bad. So 1 coil is the front as looking at the carb. Thanks, much needed.

 

[F_R]

What can I say, OMC points used to be made in Illinois, USA. Sign of he times, I guess. I'll bet the spring tension is way off on those new points also. Just a gut feeling. Besides, I don't know what the spec is/was.

 

[oldboat1]

If OMCs are that far out, might be an odd case where Sierra or Mallory points fit better. Sounding like a crap shoot. Don't think there are too many ways to mess up installation (spring inside the vertical boss, then clipped. Contacts lined up, and fit down on post with the little wire clip in place. I keep the old clips, as they pop off onto the shop floor real easily.)

 

[webbrs]

One set lines up perfectly the other is off center horizontally but makes full contact otherwise. The set I took off was the same way. The spring is pretty stiff, it seems to work fine just way too long. I had to go aftermarket on the float needle, they sent one that was all steel from OMC. Didn't have the viton tip. I made em send me the sierra which is supposed to be viton, so it is all a crapshoot I guess.

 

[oldboat1]

boy, just doesn't sound right. Using the right screw hole to attach the points? A pic might help, if you could.

 

[webbrs]

I keep trying to upload pics but it says I'm exceeding 400000 k. odd, it let me before. I never took out the eccentric and there is only one other hole save the condenser mount.

 

[oldboat1]

identical install to the set that fits(?) done a lot of them, and still do it one side at a time if I can.

 

[flyingscott]

If the clip comes off it's magnetic sticks to the flywheel and flies past the coil and tears it it up. You may need to exchange your points for different ones or put the clip on from the top and make sure it doesn't interfere with the points.

 

[webbrs]

I put it in from the top and set the points, no worries I'm more trying to wrap my head around this idea of setting the points to open at TDC. All that I have had experienced with is that the ignition should fire around 3* past TDC. Ignition shouldn't occur at TDC as it puts to much stress on the rod bearings.

 

[racerone]

????-----I think you are mistaken by thinking that ignition does NOT occur before TDC , Very mistaken.---Sorry.