1972 50 hp Johnson 50ESL72C Starting Issues

Freddyb18

Cadet
Joined
Nov 2, 2011
Messages
14
Hello all,

Since I purchased the motor, I have replaced the starter solenoid, impeller, plugs, rebuilt the carbs, and purchased a new starting battery.

After rebuilding the carbs, it was suggested to me that with my motor I should back out the jets about 3/4 of a turn and fine-tune from there.

I adjusted the low speed jets on muffs at idle, which I just read on another thread is not a good thing...

With my brand new fully charged battery on muffs in my driveway, the puppy fires right up.

Yesterday, I started it a couple times in my driveway on muffs (after changing to new plugs) to be sure that it would start and I took it out to the water. I put it in the water and it seemed that I was not getting spark... After cranking on it for about 20 minutes or so, it fired up. I headed out and it died on me before I could get outside of the no-wake buoy.(Which is actually a decent distance at this location.) I tried to start it periodically for the next hour or so as I headed back to the ramp with my trolling motor. I tied up to the dock, and tried it one last time. VROOM! It sat and idled for about the same amount of time and died again.

Last night I took the battery off of the charger and started it on muffs. I started it 10 times at least. I let it run for different periods of time at idle to see if it would kill itself, but it ran and started fantastically.

This morning, after placing the battery on the trickle charge all night, I took it to a different location. I started it ONE TIME in my driveway (again, beautiful). I took it out to the water and it acted like the battery was dead... After cranking for 20 mins or so, the motor fired up. I got it past the no-wake buoy (much shorter distance here) and ran it WOT. Up on plane, full power, and sounded great. I left it running while I tossed my cast net, and it died on me after about 10-15 mins of running.

I cannot figure this out... It almost seems like there is some extreme resistance in the water. It is such an automatic start on muffs, it just seems strange that it would have these issues in the water.

I have tried taking the cover off and leaving it on, I have tried wiggling wires gently while trying to get it to start, pumping the bulb, none of which have effected anything (or at least it seems).

Hopefully, I have answered my own question here and am just not seeing it... Any thoughts?

THANK YOU !!!!
 

eavega

Lieutenant
Joined
Apr 29, 2008
Messages
1,377
Re: 1972 50 hp Johnson 50ESL72C Starting Issues

Have you verified that the gearcase is in neutral when trying to start? It sounds like when you put it in the water, you are getting resistance at the prop or back pressure that is not allowing the motor to spin at an appropriate speed for starting. That pressure would not exist on muffs. Start it on muffs and make sure you can cycle through forward, neutral, and reverse. When the electric shift (I assume that motor is a hydro-electric shift) fails, it defaults to forward gear. If it is not in neutral, there is a troubleshooting procedure that you can search for here on iBoats. Things to check are the shift switch, the shift solenoids, and make sure you have the right gearcase oil.

Rgds
 

Freddyb18

Cadet
Joined
Nov 2, 2011
Messages
14
Re: 1972 50 hp Johnson 50ESL72C Starting Issues

Thank you all for your help. After checking with a local shop we discovered that we had the wrong gear oil in it. The hydro electric shift does require a premium lighter weight oil.

Took it out with some starting issues. Fired up once and ran for an hour with no issues.

Replaced the rectifier. Took it out again. Starter decided to not engage. Replaced the Starter's Hot lead and brush with a spare. I took it out today and works better than I would have ever dreamed.

The starter...

Man, Hopefully this helps someone else out. THANK YOU ALL!!!
 
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