1975 9.9 Evinrude Spark

[mark.h]

I'm having an issue getting the top cylinder of my outboard to fire.

Its a 1975 Evinrude 9.9 (10524C). Last night I had it running and pulled the top plug boot off the plug to confirm it was the dead cylinder. There was no change to engine, so I assumed it was the dead cylinder. When I started to put the plug boot back on the plug (engine still running) it appeared that the spark jumped the 'gap' inside the plug boot to the plug and fired the cylinder (I could here the change in the engine). When I 'seated' the plug boot all the way down on the plug (as it should be) the cylinder drops dead though.

This is a new coil/plug wire/boot that I assembled myself so I may have got something wrong...

Has anyone experienced this? and if so, what did you do to remedy it?

Tonight I plan on swapping the coils to see if the problem moves from top to bottom.

Thanks in advance for your help, this looks like a great forum.

- Mark

 

[Rick.]

Re: 1975 9.9 Evinrude Spark

It would have been easier if you hadn't already changed out everything. Then I could have told you to change out everything. LOL. Take a few minutes to recheck all your connections paying particular attention to the bad plug boot connection and if you have an extra plug put it in the dead cylinder just in case it's a bad plug. Swapping the coils is a good idea too but I would check connections first. Also if you fire it up in the dark of night you might see spark jumping to ground. Best of luck. Rick.

 

[OptsyEagle]

Re: 1975 9.9 Evinrude Spark

Did you do the second part of this test, where you pull the boot off the bottom cylinder and see if the motor dies. These things run amazingly well on one cylinder. I agree that you can usually see a difference when you pull a boot of a two working cylinder motor but not always. I would suggest pulling the bottom and stalling the motor before you assume your cylinder is not firing.

The coil switch test is also useful as well as a proper external spark test. Perhaps you have weak spark. Enough voltage to jump a small closing gap as you put a boot back on but not enough to jump the spark plug gap in a compression environment. Your ignition needs to produce enough voltage so a spark can jump a minimum of quarter inch gap and optimally three eighths of an inch.

So in a nutshell, I would do a proper external spark test, then a proper plug boot pull test and then a coil swap test. I would bet with those results you will be led in the proper direction of your problem.

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

Rick - thanks for the suggestion...I'll check/clean all the connections tonite before the coil swap...hopefully I'll find something...

OptsyEagle - last night I did pull the bottom plug wire (with top wire still connected) and it did kill the engine...I'll swing by the parts store and pick up a tester on my way home

I'm concerned that I didn't assemble the metal end on the plug wire and the plug wire to the coil correctly....any tips on this???

 

[OptsyEagle]

Re: 1975 9.9 Evinrude Spark

I can't help you on the coil wire since I have never done that before but the spark tester can be homemade. I used the design from Leeroy's ramblings site with two bolts inserted into a piece of wood with a common ground. Attach a wire to the ground and you are ready to go.

Adjust the gaps between the bolts and ground to 3/8". Put the boots on the bolt ends and connect the ground clip to your powerhead and pull the cord. This is done better if you remove the spark plugs to remove the compression. You need that flywheel to really fly so to speak to generate the proper voltage. You should see spark alternating from each bolt. If you don't re-adjust the gap to about a 1/4" and try again. If you still don't then you have none or insufficient voltage for spark.

I have attached a picture of what I use from Leeroy's site.

 

[iwombat]

Re: 1975 9.9 Evinrude Spark

Sounds to me like you've got a fouled plug. Sometimes putting an air gap in front of a bad plug will get it firing again. Swap plugs and see if the problem changes.

 

[nwcove]

Re: 1975 9.9 Evinrude Spark

did you screw the boots into the wires, or just push them in? they need to be screwed in at the boot and the (wires) need to be screwed into the coils.

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

did you screw the boots into the wires, or just push them in? they need to be screwed in at the boot and the (wires) need to be screwed into the coils.

I screwed the wire into the coil but didn't have that option on the spark plug side...they came with a spring looking clip with an "L" shaped extension. I poked the sharp end of the "L" into the wire and then pushed the wire into the boot with the clip leading the way ...didn't seem like a real sturdy setup

Here is a link to a picture of what I'm trying to describe... http://www.mfgsupply.com/m/c/24-8750.html?id=ttqweQM5

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

I ordered a "store bought" tester today from local parts store...it will be here in am. Thanks for the link to LeeRoy's site...I've spent quite a bit of time on there GREAT site and great guy.

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

Sounds to me like you've got a fouled plug. Sometimes putting an air gap in front of a bad plug will get it firing again. Swap plugs and see if the problem changes.

swapping plugs did it...top cylinder fires now...curious if it was bad out of the box or fouled in the 15 minutes or so I had it running in the tank. Going to pickup new plugs in am and will try a new one & see how long it will last...what causes fouled plugs?

 

[Rick.]

Re: 1975 9.9 Evinrude Spark

I have had a bad plug right out of the box before. Actually more than once. Too rich a mix can cause them to foul but not normally that quick. Hope the plug is the fix. Is this engine now to you or have you had it for some time. Plugs should be gaped to .030. Rick.

 

[OptsyEagle]

Re: 1975 9.9 Evinrude Spark

swapping plugs did it...top cylinder fires now...curious if it was bad out of the box or fouled in the 15 minutes or so I had it running in the tank. Going to pickup new plugs in am and will try a new one & see how long it will last...what causes fouled plugs?

What spark plugs are you using?

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

What spark plugs are you using?

I'm using NGK B7HS...First time I tried these...I was using Champion UL81C...now I'm thinking of switching back!

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

I have had a bad plug right out of the box before. Actually more than once. Too rich a mix can cause them to foul but not normally that quick. Hope the plug is the fix. Is this engine now to you or have you had it for some time. Plugs should be gaped to .030. Rick.

I've had the engine since the late 80's...its been a pretty good engine but always seems to need something...I'm trying to learn how to take care of the 'somethings' myself...Thanks!

 

[OptsyEagle]

Re: 1975 9.9 Evinrude Spark

Well I have had the opposite experience on my 1975 9.9 Evinrude. The champion plugs you named caused me different problems but the NGKs you mentioned never caused me a problem. I suspect you may have another problem causing the fouling. Your spark test should be informative. If you had a weak spark or intermittant spark or even a poorly timed spark (too low of point gap) you will get a plug to foul.

How did the other spark plug, that wasn't fouled, look? Also, why did you decide to change the wires on your coils in the first place? Was there an operational problem?

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

Well I have had the opposite experience on my 1975 9.9 Evinrude. The champion plugs you named caused me different problems but the NGKs you mentioned never caused me a problem. I suspect you may have another problem causing the fouling. Your spark test should be informative. If you had a weak spark or intermittant spark or even a poorly timed spark (too low of point gap) you will get a plug to foul.

How did the other spark plug, that wasn't fouled, look? Also, why did you decide to change the wires on your coils in the first place? Was there an operational problem?

The 'good' plug was grayish/black and seemed to be working fine...

I actually replaced both coils (which came with wires/boots)...I decided to replace both coils as they were cracked and hadn't been replaced since myover heating incident...I had already replaced points & condensors and was still having problems getting it to run on both cylinders & coils seemed like the most logical place to go next...I admit I'm not really diagnosing problem but just throwing new parts at it and hoping for the best due to my limited knowledge...good news is everything is new now...

I'll have the plug tester and new plugs tonight...I'll check spark tonite on new plugs and report back...Thanks everyone for all your help

 

[iwombat]

Re: 1975 9.9 Evinrude Spark

When assembling the spring end on the coil, the arm leading to the spring should be 90-degrees from the plug wire when pushing the pointy bit in. Once it's in you flop the spring over on top of the end of the lead. It's tough to explain. I hope that made sense.

 

[Rick.]

Re: 1975 9.9 Evinrude Spark

A 75 could use some new parts here and there so I see no problem with what your doing. Probably the best item you could get for it would be an OMC service manual. There are so many procedures outlined in detail and the members of this forum will guide you when it comes to trouble shooting and good methodology. I'm thinking iwombat is referring to the spark plug boot coil not your ignition coil. Took me a couple of reads to understand that. LOL. He is one of the most knowledgeable posters on this forum for sure. Rick.

Edit: I must say this many posts into it is not the time to casually mention your overheating incident. Better tell us more about that and if you've had this problem since/before the overheat.

 

[nwcove]

Re: 1975 9.9 Evinrude Spark

overheat?......have you done a compression test since the "incident"?

 

[mark.h]

Re: 1975 9.9 Evinrude Spark

OK OK I guess I did kinda try to slip that in! Sorry!!

Here's the story...summer of 2007, I took it out and it got hot enough to kill the engine...I had to row back...

Luckily the engine did not seize...With loads of help from 'the machinist' and his web site, I rebuilt the water pump, pulled the power head and cleaned out all the water passages, replaced the T-stat, and the rubber grommet(?) where the the top of the copper water line meets the bottom of the power head (it had collapsed and was certainly contributing to the overheat problem)...then put it all back together

Sadly, I've only had it out 2-3 times since then...the good news is it was pumping out more water than I'd seen in years! The last time I had it out it appeared I was losing power to one cylinder when it warmed up...my theory was it was a bad coil since other than the driver coil it was the only electronics I hadn't already replaced...

As far as compression, I was confused on how to do the test. I thought you were supposed to measure it each pull and release pressure each time...doing it that way, I had 75 on one cylinder and 80 on the other...I have since read you pull 5-6 times and measure the cumulative pressure...is that correct? If so I'll borrow the tester again and redo it.

Well now I feel like an idiot but I still want to work through the issues with this engine and get it running properly and I'm really enjoying the process and the help I'm getting from you all. Thanks for sticking with me on this...