1969 Evinrude 55HP 3-cyl Triumph - Intermitent Spark when cranking - Why??

[john corvette]

I have a 1969 Evinrude 55 HP 3cyl- Triumph with electric shift. When cranking to start the engine sometimes produces spark and sometimes no. There does not seem to be any reason for the lack of spark on some cranking attempts. It seems random. The wiring seems in good condition. When it does produce spark the spark from the plugs is very deep blue and bright that indicates to me there is lots of voltage. However, on the next cranking the engine may produce no spark at all. It seems as if someone is flipping some phantom switch off and on at random. I see no reason why the engine produces strong spark on one cranking and absolutely no spark on another random cranking. The engine has low hours, is in excellent condition, has not been tinkered with, has 135 - 140 lbs per square inch compression cold. The engine has sat for some time in dry storage. I have started it and it runs great and idles fine. The next time I try to start it it is totally dead. There is no spark. After several tries it will fire up and run rough until it clears the raw fuel from the previous failed starts. After the engine clears itself it will start and run just fine. Then on another attempt later the engine will not produce any spark at all again. It seems totally random. What can cause this seemingly random lack of spark???

 

[DJ]

Re: 1969 Evinrude 55HP 3-cyl Triumph - Intermitent Spark when cranking - Why??

It won't start unless it is in nuetral. Are your shift switches OK?

When you have no spark, does the prop turn freely by hand?

 

[john corvette]

Re: 1969 Evinrude 55HP 3-cyl Triumph - Intermitent Spark when cranking - Why??

It won't start unless it is in nuetral. Are your shift switches OK?

What should I look for or check to see if the switches are OK?? How should I test the switches??

When you have no spark, does the prop turn freely by hand?

I will check to see if the prop-shaft turns freely when I have no spark in the morning.

Earlier this evening when I last tried to trouble shoot this problem while doing some bench testing. I had a hose on the engine to wet the impeller when I cranked it over. I had pulled all three spark plugs and had no fuel in the carbs - the cylinders were still lubed from an earlier failed start attempt. The shifter was in neutral and I tried cranking the engine. It had lots of dense dark blue spark.

I stopped cranking and touched nothing but the ignition switch. I recranked the engine a second and third time and had lots of strong spark.

I touched nothing and went to answer the phone.

When I returned and cranked the mengine again there was no spark. Totally dead and I had touched nothing but the ignition switch. I cranked the engone again several times and no spark. I tried and retried and still no spark.

I expect that when I crank it over in the morning I will get a strong spark again. This is the way it has acted since I took it from storage.

Tomorrow morning I will check to see it the output shaft is free-wheeling or if it is in gear when I fail to get spark.

Thanks for the initial push in the right direction.

 

[john corvette]

Re: 1969 Evinrude 55HP 3-cyl Triumph - Intermitent Spark when cranking - Why??

An update on what happened today.

Had a real bad problem with this intermitent spark and then this morning found a chaffed wire from the powerpack / ignition module to the coil. The blue wire that runs to the coil had some of the plastic insulation rubbed off it on a mounting screw for the coil in behind and beside where the main electrical system diode / rectifier mounts. When I repaired the bare wire the problem seemed to be resolved and the engine started great for a large number of startups. However, it is back again but not as bad.

The prop shaft does not turn when the engine is cranked over. The electric shift switches and associated mechanisms all are working as designed. The engine cranks over in neutral and cranks over well. The prop shaft does not turn.

The engine fired up great after the initial wiring repair described above. However, after several starts and stops, on the next cranking the engine again produced no spark at all. It seems as if someone again is flipping some phantom switch off at random.

I again see no reason why the engine produces strong spark on several crankings and then absolutely no spark on another random cranking.

As before, the engine has low hours, is in excellent condition, has not been tinkered with, has 135 - 140 lbs per square inch compression cold. The engine has sat for some time in dry storage.

Hold on now for my unorthodox attempt to get it started. I tried a quick and questionable emergency fix I saw a friend do on a 115 HP Evinrude of about the same year.

This emergency fix to get started is suspect but it worked for me just like it did for my friend years ago.

After the no spark issue returned I disconnected the three contact hardshell that connects the rectifier / diode ?? that sits just ahead of the coil on the powerpack side of the engine and just above the power pack. This hardshell has two yellow wires and one red wire that run down to the electronic device (rectifier / diode - that turns the a-c current from the flywheel to DC current - I think). When I had no spark on cranking I disconnected this hardshell connector. I recranked the engine and it started immediately and ran smoothly. I shut it off and restarted it several times with this hardshell disconnected. It started great with the hardshell disconnected.

I then shut it off and reconnected the three wire connector and the engine started again no problem.

The no spark still seems totally random. What can cause this seemingly random lack of spark.

What is happening when I disconnect this hardshell connection? Why will it start with this connector disconnected Then after the no spark issue seems to be resolved I reconnect the hardshell and all is as normal. What is my real problem and what should I be looking at to repair this intermirent spark issue.

What am I liable to damage with this unorthodox quick fix of disconnecting the hardshell connection?

Thanks for yesterdays feedback.

I look forward to more feedback and help.

John