1969 85hp evinrude spark question

[kaupinator]

I have a 1969 85hp evinrude electric shift. Two questions 1. When running at ide I can take the bottom plug wires off of the plugs and can not hear any difference in the motor. If I pull of either of the top spark plug wires the motor dies instantly. It seems to run pretty smooth when the throttle is opened up. The main reason I am asking is I had the boat out 2 weeks ago and it ran fine. Last weekend I took it out and could not get it to stay running. I had to start it using starter fluid and then it would die when put into gear. I got it home and in the process of cleaning the carbs with some spray cleaner realized that the battery was almost dead. I charged the battery and now it stays running and idles ok. 2. Can a weak battery cause the motor to not stay running at idle?

 

[HighTrim]

Re: 1969 85hp evinrude spark question

Welcome to iboats.


You seem to be intermittently running on 2 cylinders. You should hear a noticable drop in RPMS when removing the plug boot. What is the condition of the coil? What do the plugs look like?

Also, dont using starter fluid on an outboard, use some premixed fuel in a spray bottle.

 

[kaupinator]

Re: 1969 85hp evinrude spark question

Thanks for the quick reply the plugs are new. The coil I have no idea how to test the condition. It is located on the back of the motor, black cylinder? I was going to pull the flywheel to look at the points but it is on there pretty good. So I thought I would wait and see. There is some spark I can here the wire sparking as I put the bottom plug wire back on the plug but I do not hear any difference in the motor RPMS or smoothness.

 

[Fuzzytbay]

Re: 1969 85hp evinrude spark question

You might want to check the lower cylinders for low compression. The motor could be running on "kick n coast" the top cylinders doing most of the work, so when you remove the lower cylinder plug, which is not giving much of a kick anyhow, you don't notice a change. However the top plugs which do most of the work, cause an instant die out. It could be just the coil, but.....
if it is a compression issue, thats a much more expensive fix, I'd do the quick compression test just to be sure.

 

[kaupinator]

Re: 1969 85hp evinrude spark question

I will check the compression and post the results. I have been meaning to do that just have not purchased the gauge yet. Any ideas about the low battery and dying at idle?

 

[kaupinator]

Re: 1969 85hp evinrude spark question

Ok I have the compression results!
#1 is at 130
#2 is at 125
#3 is at 122
#4 is at 125

 

[Rscardina]

Re: 1969 85hp evinrude spark question

id say compression is good..

do you have a spark tester, the in-line variety??? I find that when you do stuff alone its helpful to get a visual..

I would get one if you dont have one...and check all four.. you might find the culprit and possible the lesser of the expensive repair as well..the coils..

 

[kaupinator]

Re: 1969 85hp evinrude spark question

The bottom two cylinders have a weak spark but do spark. What does this tell me?

 

[kaupinator]

Re: 1969 85hp evinrude spark question

With the previous question I would also like to know what the red blob is on one of the wires. Does everything look pretty normal on this motor?