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She's on, She's off. intermittent fault.

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spudgun60

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I have a springer 20ft narrowboat, about 25 yrs old with what I think is original engine. it is a Honda 9.9 outboard engine. she can run for weeks at a time without missing a beat, but then for no apparent reason she will not start. I'm sure it is electrical as power fails to reach the plugs, no spark. at the moment she has not been running for a week, this is the longest period so far. please if there is anyone who is more of a mechanic than me and has had a similar problem and solved it, please let me know. just to let you know, I've cleaned everything that can be cleaned, if this helps, it is an electronic ignition with manual choke and electric start. Yours in desperation Pete.
 
If you could post the frame serial number for the motor, we could determine exactly which 9.9 that you have.

Anytime you are trouble shooting a spark issue, you should first disconnect the stop switch. Just disconnect the two wires. Do not connect them together. Connecting the wires will kill the spark.

If it is the vintage 9.9 that I think it is, one of the two connectors on the cdi unit (the pack of cigarette sized unit on top of the motor) sometimes has connection issues that cause the motor to either run bad or not run at all. Disconnect it and make sure the pins are clean. Then give each one a little twist so that it makes better contact but still goes into the connector.

The good news...believe it or not.....is that you have no spark all the time. Makes troubleshooting easier than intermittent spark.

Go the Honda website and download an owner's manual, if you do not have one. http://marine.honda.com/support/manuals/models/BF9.9

There is a wiring diagram at the end of the manual. It does not tell you how to troubleshoot, but will help if you try to test. You will know what color leads go where.

I know you said that you are not much of a mechanic, but I don't think you want to just through money into parts, based on a similar experience from someone else.

Spark is not Rocket Science on these things...but you do need to know a little about electricity or maybe you have a friend who does. The friend does not really need to know anything about motors. Just how to read a wiring diagram and how to measure voltage and/or resistance.

You asked "what time is it"? I am about to tell you how to "build the watch".

Under the flywheel there are two sets of coils. The flywheel has magnets that move past the coils producing AC voltages. The Exciter coil produces one of the voltages to make the spark. The charge coil produces the voltage to charge the battery. Do not worry about the charge coil....it has nothing to do with spark. The output from the exciter coil is normally somewhere between 100v - 200v. I do not remember exactly...but if it has 100v, it is probably ok.

There is also a coil right next to the cam pulley, at the top rear of the engine, called the pulsar coil. The voltage from that is generally very small.....maybe .5v or so.

These two voltages go to the CDI pack. The CDI pack just acts as a switch. The pulsar coil output tells the CDI pack when to switch the 100 + volts on to the coil.

The coil then takes the 100 volts and multiplies it to 5000 - 10000 v. I do not know the exact voltage, but I think you get the picture that it is a pretty high voltage, that then arcs across the spark plug anodes.

When the stop/kill switch is activated, it shorts two leads going to the cdi and tells it not to do any switching and the spark stops.

That is why, you first disconnect the kill switch, to take an issue with the switch or its wiring out of the picture. If you get spark when disconnected, then you may have just found the problem (the kill switch).

One other thing....both spark plugs fire at the same time....everytime. So when testing spark, make sure that your tester is connected to both spark plug leads or you are grounding both spark plugs. The spark is not real big on these motors, so if unsure if you can see the spark, test it in the dark...for easier viewing.

I like to test for the voltages from the coils at the connectors at the cdi. If either of the voltages (exciter or pulsar) are not there, then the problem is either one of the coils or associated wiring. If the voltages are good going in, but there is no voltage going to the coil, then the problem is the cdi unit or connections. If there is voltage going to the coil, but no spark, then either bad spark plugs, bad connections, or bad coil.

Make sure you are using good spark plugs.....NGK DR5HS.

Like I said, this is probably more than you asked for, but there are several pieces to this puzzle and the more you eliminate, by testing and seeing what pieces work, that helps zero in on the one that is not.

Mike




I
 
Hi Mike thanks for your reply. I will print off and take with me to check all that I can check. will post my results. the frame number for my engine is 99AHCDS. thanks again.
Pete.
 
Mike - that's an excellent description of the procedure. I've copied and saved it for future reference. Thank you for taking the time to do that.
 
spudgun60,

Normally frame serial numbers consist of 4 letters and 7 digits (like BABL-1000001). What country are you in? It might be a different arrangement there.

Mike


Chawk,

Thanks. I should do that too, but I always forget or have some other distraction.
 
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I'm going to print it TOO! Thanks Mike, for the "concise" ignition tutorial!

spudgin60: I just want to point out that, on your outboard....you have two TYPES of voltage. Your starting system will use a storage battery and that will supply 12 volts....DC (Direct Current) voltage.

The testing Mike gave you for the coils in the ignition system involves AC (Alternating Current) voltage.

I bring it up because you will need to make sure that you are setting your meter to the correct "scale" for reading the appropriate voltages. Even the "pros" forget to do this from time to time.

Good luck!
 
thanks guys for all your helpful info, a sparky friend of mine has done a circuit test for me and seems to think its the pulser coil? think that's what he said, anyway, have sent for a new one, it is in the post at the moment. cant say anymore till it arrives and we fit it. will post results. thanks again.
Pete.
 
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