1955 Johnson RD17 25hp - Hard To Start

[jb93]

The post WW2 flywheels are much improved, and have never had a 50s OMC with bad flywheel magnets. Maybe if you left the flywheel off the motor for a hundred years or so it may weaken, but nothing you will have to worry about. I doubt that is the issue. I find your symptoms are almost ALWAYS dirty points. Even when new, they often need cleaning and dressing. Wrap wet/dry around a hacksaw blade, and polish those buggers to a shine. Blow off with compressed air. Dip business card or paper stock in acetone and run that through. This is after verifying they are set correctly at 020. How is the coils air gap? Maybe too big?

I pulled flywheel and dressed (again) points with 320 grit. Sprayed clean with electronic contact cleaner and wiped with paper stock. Reset at 0.020. Coil air gap set with Franks ring from this site. Absolutely ZERO spark on spark tester, which is good and my 1957 Fastwin makes it pop. If I ground the spark plug to the block it sparks the plug gap 0.030...so spark is weak. Everything is new on the ignition and redone several times. I can see having one cylinder that wasn't sparking if I happened to have got a faulty coil or condenser...but I highly doubt that all the brand new coils, condensers and points are faulty. What else could it be other than the flywheel? The magnet looks fine. I do see where at some point there was rubbing on the coils and it left some marks...but not damaged or any chunks missing.

Man...I don't know what else to do to get some sparkage??

 

[jb93]

Got a tip from an old hand. He asked what color my new coil lamination bars were. When I told him black he asked if I had to "Argue With Them" to get the sizing ring on and off...which was indeed the case. He said those are CDI coils and they don't fit proper (even though they are the right part number). I came home an reinstalled the original coils (not cracked but I replaced for posterity). Buttoned her up and I am getting 3/16" bright blue spark on both cylinders nearly every pull.

Is it normal that I would not get spark every pull...maybe getting it 7-8 out of 10 pulls? I'll probably go ahead and get some new OMC oem coils and replace the old ones anyway.

Appears my problem is solved or very nearly. I would appreciate any input on the 7-8 out of 10 sparking...if that should be a concern?

 

[jb93]

Still no joy on this motor. I am getting gas to the carb but not to the plugs. Carb has been fully disassembled (including welch plugs), soaked and rebuilt. I pulled it down and soaked it a second time just to make sure. I am beginning to think the motor isn't pulling to draw fuel in. It has good compression 90/90. How would I be able to check to see if it isn't pulling a vacuum to pull fuel out of the carb bowl?

 

[HighTrim]

Will spraying pre mixed fuel into carb throat get her going momentarily?