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This is my 1956 Johnson Javelin 30HP motor on my runabout. Apologies in advance of the long post – I wanted to try and give as much of my experience as possible to “paint the picture”
- Started this season off solid – multiple rips to water, tuned my high throttle nicely and everything seemed to be running just fine.
- Opening Day here in Seattle in early May – out on boat waiting for others. Stopped boat for a while, restarted fine. Motor died while traveling slow. Could not start the boat and eventually needed a tow to the boat ramp.
- Tested spark plugs – no spark on lower spark plug.
- Took flywheel off this weekend – replaced points and condensers. Coils tested out fine with Ohm Meter so left in place.
- BUT!!!! The “key” on the flywheel stem was sheared in half!! (this, *I think* explained some slippage I felt on the water occasionally and the fact that my top speed after tuning was 5-6 miles slower than usual) Got a replacement key and then got flywheel reinstalled. I did find that a chard of the key was touching the stem and the magneto assembly and thought maybe there was some short…
- Tested magneto with spark plug testers and both were firing great so headed to the water today…
- Was not able to start the engine except by using starter into the carb. Was able to get it started and idle for 5 minutes. Cut engine, tried to restart and no bueno. Tried more starter fluid, got some pops but never got it running again for any period of time.
- Headed home – tested spark plug /magneto and got a spark on both. Then tested both spark plugs and got a spark on both of those as well. Took flywheel off again to examine magneto. One of the points connections was off-parallel so I replaced that one so that it had a very even gap (could this have been the issue?!!! – Does not feel like it…). Set gaps to speck and put flywheel back on.
- The last thing I noticed was that after everything was installed. there was a little “play” of the magneto assembly if I put my fingers under the flywheel and lifted – just a little but did not remember ever feeling that before.
In the spirit of spark + fuel + oxygen, I feel the spark side of things is really good. The other 2 I am way less confident on how to diagnose. Any guidance from this esteemed group would be much appreciated.
Many thanks in advance.
Best,
Rich
Well I don’t know about an “esteemed group”! Most of us struggle just like you. We have all learned from doing. Fuel, spark and compression and its gotta run!
dale