weak spark

[bucs.win1@gmail.com]

I had a ground wire short out and melt the insulation on the wire. The engine was running, and I turned it off which stopped the smoking. It will not start, but it does have a weak spark on a spark tester, however, it will not jump the gap on the spark plug. The ground wire runs from the engine block to the ignition coil. I have isolated the burnt wire, it did not affect any other wires in the harness. When I checked the ignition coil, there was a loose bolt where the burnt ground wire was connect, I am thinking this was the cause of the short. I used a multi meter on the coil, it checks with in range to the ohms per my service manual for both the primary and secondary. The primary has continuity, the secondary does not. The pick up coil on the stator test fine per the ohms test, and it does not have continuity. The position sensor side of the stator tests at 0.3 ohms, the manual states the range for this test is 0.085 to 0.105. It also has continuity, my meter beeps. Is there another way to test the stator, or did I test it correctly? Does the 0.3 ohms show that this part of the stator is out of range and needs to be replaced? thanks for the help.

[99yam40]

I had a ground wire short out and melt the insulation on the wire. The engine was running, and I turned it off which stopped the smoking. It will not start, but it does have a weak spark on a spark tester, however, it will not jump the gap on the spark plug. The ground wire runs from the engine block to the ignition coil. I have isolated the burnt wire, it did not affect any other wires in the harness. When I checked the ignition coil, there was a loose bolt where the burnt ground wire was connect, I am thinking this was the cause of the short. I used a multi meter on the coil, it checks with in range to the ohms per my service manual for both the primary and secondary. The primary has continuity, the secondary does not. The pick up coil on the stator test fine per the ohms test, and it does not have continuity. The position sensor side of the stator tests at 0.3 ohms, the manual states the range for this test is 0.085 to 0.105. It also has continuity, my meter beeps. Is there another way to test the stator, or did I test it correctly? Does the 0.3 ohms show that this part of the stator is out of range and needs to be replaced? thanks for the help.

Not sure how a ground wire can short out except to a hot wire as it is grounded already.
A loose connection would not cause extra current to flow in a ground wire to melt the insulation. But it could cause the connection to heat up but probably would have just not fired properly instead.

If you are reading ohms then it has continuity.
Follow the manuals instructions to take voltages from inputs and outputs with the proper testing equipment.
make sure you take into consideration the resistance of the meter leads when taking readings.

[bucs.win1@gmail.com]

weak spark

Thanks for the response. The multi meter I have shows a resistance of 0.2 when I touch the leads together, so when I am showing 0.3 ohms when testing the position sensor side of the stator, it really is testing at 0.1 ohms after I minus off the .2 for the resistance in the tester leads. Basically, the ignition coil and the stator are testing the right ohms per the service manual. The only thing I have left to test is to see if the position sensor side is grounded. The meter I have shows continuity with anything under 0.5 ohms, and the ohm range for the position sensor side is under .085 to .105, so the meter buzzes. I am going to get a different meter to see if I can get a good test on the stator. Both sides of the stator should not be grounded, right? I have spark, it is just not strong enough to jump the spark plug. Thanks, Todd

[rodbolt17]

depends on what smoked and what your testing and why?
your description has left me confused for two days and I spent 6 years in the United States Navy's advanced electronics program.
there are simply NO sensors on the stator.
can ya post a picture of said smoked wire?
like it was said before, ground wires simply dont short out.
make sure you get in your head the difference between a poor connection(high resistance then heat) open circuits and shorts.
so my question is what are you testing?
why?
and possibly what kind of motor is this?
yamaha makes and has made outboards from a 1 lung 2HP to an awesome 5.3L V8 350 HP.
all use a slightly different spark ign.

[bucs.win1@gmail.com]

The confusion is coming from my inability to properly explain, so let me try again. This is on a Yamaha 4x4 (2004 bruin 350), I know this is an outboard engine forum, when I call for parts information they recommended I try this forum. I had a wire in the wire harness get hot and melt off the insulation. It is a black wire and when I chased it through the harness, it runs from the engine block to the ignition coil. The bolt on the ignition coil that held this wire was lose, so I assumed that this was the cause of the over heating. I shut off the bike, and it would not restart. I have a weak spark (using a spark tester), however it will not jump the gap on the spark plug. I used a multi meter on the ignition coil, and both the primary and secondary circuits on the coil check out to the correct range of ohms. Next I tested the wires running from the stator, they also check out per the ohms range listed in my service manual. I am going to run through the wire harness again tomorrow to make sure I don't have any other wires with broken insulation. Just looking for some other areas to test or to look at. Thanks for any help.

[99yam40]

I have never worked on a yamaha bike, but if you have a service manual for it , I am sure it will have specs for the voltage inputs and outputs to the ignition system and tell you what kind of test equipment is needed to take the readings.
I would think that if that connection for the coil got hot enough to melt the insulation on the ground wire, the wire tied to that connection point inside the coil probably got just as hot and is shorting out some of the winding so you need to be testing as the manual states.
You probably need to find a bike forum