Weak Spark

[tbfosback]

Ok here goes. I have a 1960 18hp Evinrude Model #15032. Here is the list of what has been done so far...
Compression is 117 lbs even on both cylinders.
Fully rebuilt carb including all orifices, float, needle and seat..
Set both the high speed and low speed jets using Joe Reaves techniques...
Resealed the lower unit. Replaced the water pump impeller and thermostat.
New fuel pump (could not find rebuild kit for the original).
New fuel lines.
New spark plugs.
New plug wires.
New coils, points and condensers.
Coils are set as close to flywheel as I can without rubbing...
Points were set with a Fluke meter and verified with a timing light.
The problem is I still have weak spark... it will jump about 1/8" gap but not a 3/8"gap.
This makes it hard to start... I bypass the thottle limiter by putting it in gear to give it more fuel.
Once it warms up it will start with 1 pull in neutral with no problem.
Anyone have any ideas?? Bad magnet in original flywheel?? If so how do I test it??

 

[Daviet]

Re: Weak Spark

Any rust or corrosion on the coil laminations or the magnets in the flywheel?
I always use emory cloth and clean them up, to make sure the air gap is as close as possiable.

 

[boobie]

Re: Weak Spark

Are the points clean and adjusted properly??

 

[tbfosback]

Re: Weak Spark

Both the coils and point sets are new. The coils tested good via a fluke meter with the air gap being set about as close as I can without rubbing the flywheel. The points were set via a fluke meter and verified by a timing light. The coils look great as do the points. The flywheel does show rub marks inside of it from mis-adjusted coils (from a prior owner)...

 

[lindy46]

Re: Weak Spark

Did you clean the points after you installed them. Any oil, even from your fingers, could limit the spark. I usually spray the points with carb cleaner after installing.

 

[orbanp]

Re: Weak Spark

Ok here goes. I have a 1960 18hp Evinrude Model #15032. Here is the list of what has been done so far...
...
Bad magnet in original flywheel?? If so how do I test it??

I was about to ask this!
Check with some ferrous material, how strongly attracts it. Compare it with another known good flywheel.
Handheld magnetometers are not that cheap...

Good luck, Peter

 

[tbfosback]

Re: Weak Spark

I did clean the points after I installed them. My flywheel seems to have good magnets but I do not have another known good flywheel to compare it to.
Can you use the flywheel from an electric start motor on a rope start model??
I am about out of ideas here..

 

[ultra353]

Re: Weak Spark

Omc point ignition system will only jump about 1/4" gap. Is your spark a nice blue/white that has a good snap to it?

 

[oldman570]

Re: Weak Spark

Omc point ignition system will only jump about 1/4" gap. Is your spark a nice blue/white that has a good snap to it?

^1 older OMC point ignition sets the timming and one has to be sure that the points both open at the same spot for good starting. You may want to set them to open a little sooner or later between the timming marks. If the flywheel is not torked down will effect the fireing of the plugs alos as the magnets are not all the way down and centered with the coils. Yes some flywheels will work on both depending on if they have bolt on gears or pressed on gears. I just did a tunup on a 1967 20hp rope start that had a electric start flywheel on it. JMO

 

[tbfosback]

Re: Weak Spark

Yes my spark is a nice blue/white. But I thought it would jump a 3/8" gap. It does jump a 1/8" gap great but not so good even on 1/4".
I will reset my points to open on the early stage of the gap and see if that helps.
I was wondering about the flywheel because I may be able to come up with one from an electric start model. Of couse it is already missing the starter and all of the mounting hardware and connections...
I will keep you all posted on the progress.......

 

[HighTrim]

Re: Weak Spark

The manget should pull a screwdriver out of your fingers from about an inch away and hold it vertical.

That being said, I have hundreds of 50s OMCS, and have not found a faulty magnet yet. It is rare.

Take a clean business card, and run it between the points. Better yet, dip it in acetone.

You say you set the points, but how did you set them?

 

[tbfosback]

Re: Weak Spark

I set the points with a fluke meter... Here is a video of the procedure that another member posted up...
http://youtu.be/ga1Cjymj6ms
Except on my motor I just used the kill switch wires instead of temporary wires.
I will try the business card on the points...

 

[Daviet]

Re: Weak Spark

When you have the flywheel off, check and see if the points have a .020 gap when the rubbing block of the points is aligned with the keyway on the cam for the points.