1976 Johnson seahorse now no spark

[Jeffdoss]

Changed driver coil Friday got plenty of spark but wouldn't fire up and run so after checking everything 10 times ended up changing plugs yesterday and it fire right up and ran so today went to start it up and wouldn't fire checked plugs and now no spark again I had a guy work on it a couple months ago and done same thing to him does anyone have any idea any suggestions would be great

 

[boobie]

Got a model # ??

 

[Jeffdoss]

35e76s

 

[boobie]

Have you got the breaker points good and CLEAN and set properly ??

 

[Jeffdoss]

Yes did that today to after it wouldn't start they are brand new and the condensers

 

[boobie]

How did you clean them ??

 

[Jeffdoss]

Sorry said it wrong put in a new set today gapped at 0.20

 

[tomhath]

Changed driver coil Friday got plenty of spark but wouldn't fire up and run so after checking everything 10 times ended up changing plugs yesterday and it fire right up and ran so today went to start it up and wouldn't fire checked plugs and now no spark again I had a guy work on it a couple months ago and done same thing to him does anyone have any idea any suggestions would be great

A tiny bit of moisture might be enough to ground the ignition. Check everywhere for worn or cracked insulation: kill button, connections to the points, plug wires, etc. Especially if it was working on a dry afternoon but won't fire in the morning when it's damp.

 

[oldboat1]

breaker points would be .020. Plugs normally .030. In and out spark might be spring connectors in the boots -- spike needs to contact wire core.

 

[Jeffdoss]

Do u think it could possibly be grounding out and burning the driver coil up??

 

[gm280]

Do u think it could possibly be grounding out and burning the driver coil up??

If you have a meter you can verify the driver coil. If it reads to ground, you have a problem. If it doesn't read at all, you also have a problem. According to my Johnson factory shop manual for my 1976 40 HP engine, the driver coil for a manual starter should read 1.45 ohms +/- .4 ohms and for an electric start model 2.70 ohms +/- .7 ohms. I can't say for certain that yours would be the same. But they could read pretty close. JMHO

 

[Jeffdoss]

Does it need to be hooked up to check it or can I take it off and check it ??

 

[Jeffdoss]

Ok appreciate it but does the coil need to be hooked up to read it correctly??

 

[gm280]

Does it need to be hooked up to check it or can I take it off and check it ??

If you are going to check the driver coil, It has to be disconnected for the reading. But as you read across the wires from the driver coil, You should get readings pretty close to those I posted above. Then take one lead of the meter and touch either wire of the driver coil and the other meter lead and touch it to a ground point. You should not read anything what so ever. If you do the driver coil is shorted to the core and in turn ground. If it doesn't read anything, you are good to go with the driver coil anyway. JMHO

 

[Jeffdoss]

Ok thanks I will do that in just a few My mind is beyond exhausted thinking of everything it could be to be running fine then cut off and not crank anymore

 

[Jeffdoss]

Checked driver coil with ohm meter was 2.4 ohms so it's good guess it's time to start chasing wires and checking the whole electrical system

 

[gm280]

Checked driver coil with ohm meter was 2.4 ohms so it's good guess it's time to start chasing wires and checking the whole electrical system

Well that is a good thing. Now you know the driver coil is good and can rule that part out as the problem. So move onto the next part in the ignition system and check that out in the same manner. Check the points, condenser and the spark coils as well. Just don't jump around, go after it in a systematic fashion and either verify parts are good, or bad. That way as you prove parts are good, they are removed from the problem search. JMHO

 

[Jeffdoss]

I really need a service manual so I know the ohms everything is supposed to be but I'm gonna change points and condensers again is they're anyway to check them with a meter???

 

[gm280]

I really need a service manual so I know the ohms everything is supposed to be but I'm gonna change points and condensers again is they're anyway to check them with a meter???

Actually Jeffdoss there is a very easy way to test both points and condensers with a standard meter. Measure the points closed with a meter (resistance setting) to verify they are closed and contacting each section well. There should be near ZERO ohms closed. Anything about zero is not good. There could be a film on the contacts causing such resistance. So use a piece of 600 grit (or higher) wet/dry sandpaper and clean the surfaces smooth and clean off the contacts with Alcohol, Lacquer Thinner, Carb Cleaner Spray or even Acetone. Of course they shouldn't read anything when opened. For the condenser, which are really just capacitors, you can read across the condensers and see the meter needle spike quickly. Then reverse the leads and see it again. And every time you swap leads, it should jump a little, IF you are using an analog type meter. For a digital, some DVMs have a capacitor setting on them and you can read them direct. If you don't have either situation, you can simple check them for short. But if you still suspect the condenser(s), you can always run the ignition setup with out the condenser connected up to see if you get any spark. The condensers are there to keep the points form arching and burning over time. Next would be the spark coils. Again you have a primary side to check and a secondary side. The primary side should read a low resistance and the secondary side a lot higher resistance. If all that checks out correct, you should have spark. JMHO

 

[Tim Frank]

Of course they shouldn't read anything when opened.

????? Very confusing statement.

If you mean with the points open, you shouldn't try and measure across them because of all the loads attached, I'd agree.
If you meant that with the points open the reading across the points will be zero, that is incorrect.

Otherwise, the points should be disconnected from all circuits and when open, resistance across them should be infinite.