Basic Engine Theory

[bigbadjim]

If I increase points gap will I be able to get a hotter spark? Weak spark- New coil gap is only at .010?

New igmition system- Yes I did put a condenser in

 

[F_R]

Re: Basic Engine Theory

The dwell time does matter on an automotive battery ignition system such as you are trying to create. Beyond that, you are more or less treading in unknown territory. I know a lot of people have attempted the conversion, but I haven't heard any long term success stories. Be sure to let us know if you do succeed.

 

[bigbadjim]

Re: Basic Engine Theory

I will post my results once I have succeeded.

 

[Chris1956]

Re: Basic Engine Theory

When you say "hotter spark", you mean greater voltage? if so, you need to up the input voltage to the coil, since the voltage output of the coil is proportional to the difference in the primary and secondary windings.

When you increase the voltage to the coil, it will tend to jump the point gap more easily. I do not know what this will do to the spark or the condenser.

A lot of aftermarket CDI units are available to work with battery-coil-points igntion systems. These can power the coil with 300V, yet put just a few volts across the points. This avoids burning the points and allows a std condenser to be used.

There are other kinds of aftermarket ign systems that use special coils, no points, and other modifications.

 

[JB]

Re: Basic Engine Theory

Do you think you might tell us what brand and model engine you are messing with??

There is no answer to your question without knowing what system you have.

 

[bigbadjim]

Re: Basic Engine Theory

I am working w/ a 1969 85HP Johnson. Has points ignition-- trying to convert over to standard automotive coil with w/ internal ballast and condensor. I am getting spark out of the coil wire but cant get it to come out of the cp any ideas? No fire at plugs but getting spark out of coil. How does this cap transfer its energy through the caap I dont see how it does this. Is it firing all four plugs at once? every time?

 

[bigbadjim]

Re: Basic Engine Theory

Also Anybody know how rotorless cap fires onoutboard? I cant get plugs to fire but I can get good spark out of coil. I am stumped. even changed out cap with spare I had and same thing.

 

[F_R]

Re: Basic Engine Theory

Rotorless??? Well no wonder it doesn't work. There is supposed to be a rotor in there,

 

[bigbadjim]

Re: Basic Engine Theory

FR Thank you! she fired right up and the ignition sytem seems to be working fine- new automotive coil and etc. I didnt realize it (rortor) was gone as someone had gotten to it before I did. Having worked on alot of motorcycles and other stuff didn't realize it didn't have one.Anyway she runs. but alas its something else, I also had pulled the lower unit and had a heck of a time alignig the lower unit. I dont think I got it aligned right with the cooling tubes as after about 5 min of run time it turned on the hot light. I was right by the ignition switch when it went on so I dont think anything was damaged. I am going to take it around the corner and have the Evinrude dude pull & reseal it and realign it. Any thoughts on what the costs should be assuming parts are not damaged?

Thanks Jim