1955 fastwin weak spark When throttle is turned up???????????

[Anthonyfasttwin]

Hey all I have been working on my ignition system replacing everything when I do a spark test I get a good spark when The throttle is turned down. When I turn it up I get no spark. Any Ideas???????????

[kbait]

Sounds like it's arcing out the plug wires when they're 'moved' when advancing armature plate? Both at once would be unlikely. Did you 'replace everything' correctly?

[lindy46]

Sounds like it's arcing out the plug wires when they're 'moved' when advancing armature plate? Both at once would be unlikely. Did you 'replace everything' correctly?

Ahh - good thought. Did you replace the spark plug wires? Other than that, I can think of no reason why advancing the throttle would affect spark.

[Chinewalker]

Are the plug wires firmly "screwed" into the coils? Only other thing I can think of is that your mag plate is loose or out of whack and the point gap is closing when it is turned...

[Anthonyfasttwin]

I replace the plug wires screwed them in good I cant figure it out.

[nwcove]

are you using a spark tester? you should be able to see if its loosing spark gradually (cant imagine it) or if its losing it at a certain spot. (most likely). use a spark tester, find the spot where it looses it, remove the flywheel and have a GOOD look at things.

[kfa4303]

When in doubt, take a step back and start fresh. It can only be one of a few things. If you got a new tune up kit with points and condensers and each set of points are properly set to .020" at the TOP position on the crankshaft cam, then you can eliminate them as a problem. If the coils are not damaged, cracked, or scorched, then they should be ok as well. If you've twisted on new, copper core spark plug wires on to each coil post, then they can be eliminated. If the crimp on boots are properly attached, then all that remains is are a couple new spark plugs. Champion J4C or J6C should work fine. That's really all it can be. Use a proper gap tester, available from any auto parts store, to verify spark. You should get a bright, blue spark that jumps a 1/4" gap. This link may help.

http://www.outboard-boat-motor-repai...%20Tune-up.htm

[HighTrim]

I think you should check out the armature plate as mentioned above.

[Tim Frank]

One problem is that you have now got six or seven threads running about the ignition system on this motor and the work that you have done on it.

This fragments the information, wastes responders time repeating stuff that was dealt with already, hides important clues that might help us to help you, and can be frustrating.

This should have been a continuous thread, and what is significant is that you had trouble with the mag plate already. You may not have the coil screws properly installed which would account for it being loose.
Also, any chance you used automotive plug wire instead of marine?

[Anthonyfasttwin]

Ok so After many hours of head scratching I finally figured out what the problem was. On the Arms of the points, the end where it touches the round magneto cam. When I put the flywheel on the first time the magneto cam was up because of the spring and when I pushed the flywheel down it messed up the ends of the Arms. I got a new set of points and it worked like a charm. Thanks for all the help guys It was my mess up