I never met an outboard I didn’t like until now – 1960’s 40Hp Evinrude

[raglover]

Are all the linkages still on the carb? Maybe one shook loose? I had this happen on a big twin and it gave me fits until I found it on a previously good running motor.

Another item on a big twin was a cracked cam all the way through where it sat over the pin on the crank. Looked fine on the motor but would open up when turning on engine and through off timing.

In both cases mine would run very poorly or at least pop but perhaps worth a look

[kevinrude]

A little out of my league here, but I am currently working on a 1963 28HP Johnson which, I believe, has some similar characteristics to your motor, so here goes:
(1) Does the motor have a ‘kill’ switch/button? If so, is it engaged?
(2) Does the motor have that annoying fuel efficiency contraption? If so, is the linkage between that and the throttle set up properly?

Other than that, I remember hearing somewhere that ‘bad’ coils will work for a while and then crap out once they warm up. But, if that were your problem, I suspect that the motor would have quit sometime during your initial 20 minute test.

About the only other thing that I can think of is that perhaps your initial run loosened up some crud in the carb or the fuel tank and said crud is now plugging something up somewhere in the fuel delivery system chain.

The prior suggestions are probably better than these, but I thought I would throw my 2 cents worth in (1 1/2 cents accounting for inflation).

Good luck!

[wedgie]

Is it possible that even though there is spark that the Atoms have failed, and wont produce enough fire under compression. Maybe swap in some different ones, or if you have the original points and caps try those.

Where do you mount them Ron? I have a set on a 33hp Evinrude SkiTwin. Initially I mounted them under the flywheel, but thought better of it and moved them out onto the side one of the brackets. I still haven’t run it on the water, but hope to sometime this summer. Runs great in the barell. too bad the Atoms are NLA.

[rvpapasso]

Just to catch up……

The carb linkages are all attached and verified to be working at each “crank” session when the engine would not start. The engine does not have a kill switch but shuts the engine off with the ignition switch that connects the two mags together. I disconnected one mag from the switch to ensure an intermittent ignition switch was not shorting the mags together. The engine does have the fuel economy linkage and this checked out to be adjusted properly. The vacuum cutout is working properly and tested.

I have been using the ATOM modules on my 1960 Johnson 40Hp for since 1996, on my son’s 1967 33Hp since 1998, another big twin since 2000 and this engine since it was brought back to life 3 years ago. I have never had one module fail and these motors are regular runners.

On all the engines I installed the ATOM modules on I always mount them to the side of the block. When you do this it is imperative that you run a braided ground strap from the block to the mag plate. The current between the magnetos thru the mag plate and the block can be impeded by the grease allowing the mag plate to move with the throttle. I learned this one frustrating day on the water!

Given my history of the ATOM units and never had a failure I find it unlikely that both units failed at shut down on the second barrel run, especially when the visible spark was bright blue when checked. I will be going back to work on this engine next week and will start with the simple first, new spark plugs.

Thanks

[george-emmanuel]

Here’s another thought. When you shut it down the agitation in the float bowl stopped which would allow and sediment to settle. It is possible you’ve now got a clogged carb.

[olcah]

This afternoon I was struggling to bucket start an RJE-18 I acquired and worked on this winter. The motor had no interest even with mixed gas directly into the cylinders. Before supper I read this thread. Afterwards I took the plugs out of my RD-15A that did run in the bucket today. Put them the in RJE-18. Fiddled with the carb needles. Engine soon started and settled into a nice slow smooth idle. You have to love this site…

[1946zephyr]

Never give up!! These old big twins are tough and always prevail.

[kees]

quote Wedgie:

Is it possible that even though there is spark that the Atoms have failed, and wont produce enough fire under compression.

For what its worth; Use
*New coils,
*Copper core sparkplug wire,
*NON resistor sparkplug caps

[rvpapasso]

Just a quick update…….have not run it again but closer examination in the daylight showed the coil laminations were splayed out and rub mark on the magnets. This was caused by super excessive wobble on the magneto plate. Since we are using the ATOM igntion modules instead of points this does not affect spark however that much wobble to cause the ru bmarks can’t be good! My friend is switching out the mag plate with one from a spare poarts motor which has minimal wobble. Thsi could be the magic bullet. WIll updated again on the next session. Thanks!

[Author]

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