no spark with plugs in

[srl123]

Hi-I have a 1977 johnson 85hp. With the spark plugs in, I get no fire at all. With the plugs out, I get good fire. RPM's are well over 300. Checked kill circuit and rectifyer-no change. Help.
Thanks

 

[F_R]

Re: no spark with plugs in

Hi-I have a 1977 johnson 85hp. With the spark plugs in, I get no fire at all. With the plugs out, I get good fire. RPM's are well over 300. Checked kill circuit and rectifyer-no change. Help.
Thanks

How do you know the rpms are over 300? Well, ok assuming they are, then it still isn't developing enough voltage with the difference in rpm between plugs in and plugs out. Can be the charge coils on the stator or sensors on timer base. When you checked the kill circuit, did you check it by disconnecting it? Rectifier has nothing to do with it.

 

[srl123]

Re: no spark with plugs in

Yes, I diconnected the wire per manual instructions.

 

[outboardnut]

Re: no spark with plugs in

check your starter, battery, and battery cables

Make sure you are using a good battery with a high cold cranking amp ratings.

On old V-4's I like to buy the biggest truck battery I can, 1000 cold cranking amps is what I am currently using.

Also 300 RPM isn't enough on those if I recall, you need up around 400 I believe. Tach it with the plugs out, and put one plug in at a time and see what RPMS you are losing spark at.

Easy fix though, bigger battery or maybe time for battery cables and a starter.

 

[srl123]

Re: no spark with plugs in

Thanks, I'll try all of those. It would be nice if it is that easy of a fix. Thanks again.