electronic ignition

[joho5]

I just started working on an 87 9.9 Johnson motor. This will be the newest motor I have ever owned, and the only difference is the ignition components. This one is electronic ignition.

Could someone just briefly explain to me how electronic ignition works and when you are maintaining it, do you have to time it, etc...?

thanks

just trying to get a better understanding.

 

[F_R]

Re: electronic ignition

To simplify: A "charge coil" under the flywheel generates about 300 volts AC. That is rectified to DC and stored in a capacitor in the power pack. At the correct instant, a magnet passes by a sensor, also under the flywheel, which generates a small voltage that turns on a SCR (electronic switching device), also in the power pack. When the SCR switches on, it completes a circuit from the charged capacitor to the primary winding in the extermally mounted spark coil. That 300 volt surge induces a high voltage in the seconday winding, producing a spark to the plugs. There is a SCR for each coil. The engine is stopped by grounding the yellow/black wire going to the stop switch. That shorts out the capacitor.

Spark advance is adjustable. Don't mess with it unless you have good reason to suspect it needs it. Then start with a service manual to get it right.

Other than that, there is no maintenace other than checking for worn wires, corroded connections, whatever.

 

[coolguy147]

Re: electronic ignition

make sure u dont have cracked wires and dont i mean dont pull the spark plug wires off with ur bare hands!!! been there dont that ouch 300 volts man kinda a lot. use a big copper glove so it will hurt more lol jk jk jk

 

[F_R]

Re: electronic ignition

Actually, 300V is the input to the coils. The output to the plugs is in the k-thousands. It will throw a 1/2" lightning bolt with ease. Or knock you right out of your BVDs. Do not touch!

 

[joho5]

Re: electronic ignition

I dont have a manual for this motor and the setup is working correctly, but is it easy to set the timing on the sensors if ever needed?

also, what is the life span of these electronic ignition components?

 

[lowkee]

Re: electronic ignition

If I were to put a rule of thumb to electronic ignitions.. If the engine starts, it's working.

Think of it as your digital camera.. If it turns on and takes photos, you use it and leave the innerds alone.

This may seem a simplistic viewpoint, but I've found fuel/air cause many many more issues than spark. If you're looking to twiddle with your engine, rebuilding the carb will likely result in the best return.

 

[jay_merrill]

Re: electronic ignition

Actually, 300V is the input to the coils. The output to the plugs is in the k-thousands. It will throw a 1/2" lightning bolt with ease. Or knock you right out of your BVDs. Do not touch!

Yup. On my 1972 Johnson 65hp, the output voltage from the ignition coils is 30,000 volts, to be exact. That is why I shut my motor down every time I need to do something involving the spark plug wires - I don't even fool with them using insulated pliers!

 

[kaferhaus]

Re: electronic ignition

Unless the components have been removed for some reason, once properly set the timing on an engine equipped with electronic ignition should never need adjusting.

Leave it alone!

 

[jay_merrill]

Re: electronic ignition

The best thing that you can do to better understand your motor, is to purchase a factory service manual. The manual will tell you when to check timing, and will describe the procedure to do so. Manuals are available right here at iboats, and in a few other places.

While it is true that you won't often have to adjust timing, there are some circumstances in which you might. For example, in some OMC motors with CD ignition, timing should be checked if the power pack has been replaced.

In the mean time, here's a site that you might find to be interesting.

http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm

 

[Boatist]

Re: electronic ignition

The procedure is very much the same as with older motor only difference is no points that can affect timing. Only time I have seen the timing off is when the flywheel key was broken but you should have a timing light and know how to do it. Buy the Factory Manual as it is the very best. It will save you time in any work you do and you will always have the right procedure. It is the first tool I buy weather it be a car, truck, I/O, or outboard.

If your going to time the motor with no manual (not recommended) then I would at least post your questions in the Evinrude outboard motor Fourm.

 

[F_R]

Re: electronic ignition

The main reason they get out of time is somebody sees that adjustment that seems to limit the throttle. Aha!!, they say. Back that off a few turns and it will go faster. Not.