1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Clippership821 · Aug 17, 2011

The brush on my old cap broke in half after 50 years. Not a bad record. I've got the replacement coming. Is it difficult to get the spring out of the old cap? I don't find a procedure for doing this. Also, been going through a lot of rotors lately. Would it be worth just replacing the whole cap? It's available as a vintage part. Thanks in advance for your responses.

Chris1956 · Aug 17, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

What goes bad on your rotors? I would think they would last a real long time.

I think the spring just pull out, but I really do not remember,

Clippership821 · Aug 17, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Not sure on the rotors. I just don't get any spark and once I put a new rotor in, she fires right up. Thanks for the response.

boobie · Aug 17, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

The rotors were not known to have lasted to long but I would check all the resistance values in the cap. If they are to high they could cause the voltage to build and take out the rotor.

Chris1956 · Aug 18, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Boobie, How would the voltage build "take out the rotor"? The rotor was a solid flat piece of brass fastened to the plastic rotor base.

Clippership821 · Aug 18, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Thanks for all responses. I'm thinking the reason for no spark is because the brush was probably original and leaving a lot of carbon build up on the rotor. Let's see how the new brush and spring works on it and I'll keep you all posted. I still have all my old rotors. I'll polish them up and give it a go. But, I tend to agree with you Chris, not a whole lot to go wrong with a straight piece of metal...

Daviet · Aug 18, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Excess voltage will burn a hole/crack under the flat piece of brass through the plastic rotor and short out on the dist shaft. If you have a coil checker it's easy to check.

Clippership821 · Aug 18, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Daviet said:
Excess voltage will burn a hole/crack under the flat piece of brass through the plastic rotor and short out on the dist shaft. If you have a coil checker it's easy to check.

Sorry, what's a coil checker? Also, what would cause the excess voltage and would that blow out my brush as well? thanks Daviet

Clippership821 · Aug 19, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Chris1956 said:
Boobie, How would the voltage build "take out the rotor"? The rotor was a solid flat piece of brass fastened to the plastic rotor base.

I don't think they make them out of brass anymore. The ones I get look like steel.

boobie · Aug 19, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

Daviet, you beat me to my answer. As they say, "great minds think alike". I don't know how many I found over the years using a coil tester and checking the rotor and found it grounding out to the dist shaft. The dist cap should be checked for zero resistance on all wires and the cap itself from the coil to the brush and spring.

Clippership821 · Aug 20, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

How do you check with coil tester? Sorry, I'm a novice at troubleshooting this problem.

boobie · Aug 20, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

You'd have to find an "Old" OMC dealer in you area and an "Old" mechanic. They should have a coil tester and the mechanic should know how to test the cap and the rotor for any high voltage leaks. A coil tester was mainly used in shops years ago. Now it's all laptops.

Clippership821 · Aug 21, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

There's no way to test it yourself? I've done everything else on this boat.

boobie · Aug 22, 2011

Re: 1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

You have to have a coil tester to produce the high voltage to check for any high voltage leaks. The only other thing you can do is just replace parts till the prob is cured.

1961 Johnson Seahorse 75hp V4SL-13 Brush and Spring assembly replacement on cap

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