1973 Evinrude 85 HP - No Spark - One Bank

[RDJuhl]

Hi everyone,

My engine is an Evinrude 85393M.

I have owned this motor for a year, and have had intermittent starting issues, as well as spark issues. Last week, I finally started prepping the boat for the summer. I replaced the plugs, fuel filter, cleaned the battery terminals, ensured a charged starting battery, fresh fuel, etc.

The engine fired right up on muffs in the driveway, and did so on 3 different occasions (hot days and cool days). I also verified via spark tester a strong spark on all four cylinders. I also used a timing light to verify consistent spark when running on the muffs.

Went to the lake on Saturday...it would not start...it would fire occasionally, but would not start.

I got it running on the ear muffs again tonight, but using the timing light, I verified it was only running on cylinders 2 and 4. Cyl 1 and 3 were not firing at all.

According to CDI, I need to swap the timer base wires #1 and #3 pair with #2 and #4 pair to see if the no spark follows.

Questions
1 - Are the timer base wires I need to swap in the powerpack, or under the flywheel?
2 - What is the next step if the problem follows the swapped wires?
3 - Would a worn wire cause this type of intermittent spark issue?

Thanks for any help...I want to take this in steps to ensure I only replace what needs to be replaced.

 

[Daviet]

Re: 1973 Evinrude 85 HP - No Spark - One Bank

1- You switch them at the power pack.
2 - If the spark moves with the wires, the pack is defective.
3 - I guess a broken wire could cause the problem, but a broken wire should be easy to see.
You also have 4 ign coils, strange that 2 would fail at the same time, but I have seen stranger stuff. You can also swap coils and see if the problem moves.
If you are going to maintain and repair you engine yourself, you might want to think about getting a factory manual. It will have all the test procedures to help you find the problem and not replace good parts.

 

[RDJuhl]

Re: 1973 Evinrude 85 HP - No Spark - One Bank

Thanks Daviet - I should have asked one more question...if the problem does not move with the wires, does that indicate a bad stator?

Also, since this seems to be "intermittent"..sometimes we have spark, and sometimes not...would a bad power pack act like this?

 

[Daviet]

Re: 1973 Evinrude 85 HP - No Spark - One Bank

I supposed it could be a timer base or the power pack. This is where the manual comes in handy. Any electrical componet can act like this, sometimes you have to trouble shoot the engine at temp to check some componets.

 

[emdsapmgr]

Re: 1973 Evinrude 85 HP - No Spark - One Bank

It's a little harder to diagnose the power pack when the engine has only one, like yours. You will find some excellent troubleshooting infomation at the cdi electronics website: cdi electronics.com.