1975 Johnson 135 weak spark in #1

[fseventy]

1975 Johnson 135. Carbs and waterpump rebult 2 years ago. Gas tank cleaned out this year. Compression 125-135 in all cylinders. Looks to be mostly origional except new starter. <br />Engine runs great for 1st 5 minutes than power drops considerably. Determined that it had weak spark in #1 cylinder (pulled the plug while running and not much change in #1, plus it just had a weak sounding spark compared to other cylinders) I started with the switching coils #1 with #2, but the problem stayed in #1 cylinder. After running poorly like this, the three other plugs are "used" and have carbon on them, while #1 is clean and wet with gas/oil.<br />ALSO... the rectifier is dead. I did the test and it failed, plus no change in voltage from idle to WOT.<br /><br />Do I test for the power pack next???

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

I'm currently trying to troubleshoot this same exact problem with my 1974 Evinrude 135. If you find the solution please post it here.

 

[buddyholly]

Re: 1975 Johnson 135 weak spark in #1

i had a problem like yours and found that i had the wrong brand plugs in it and also i rebuilt the carbs. the thread is on the forum. it is rebuilding and not getting soaked. my motor is a 1975 115 johnson.

 

[Solittle]

Re: 1975 Johnson 135 weak spark in #1

Before you check the power pack swap the plugs & wires to see if the problem moves. If not check the pack.

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

So Party Barge... What cylinder had the misfire in it? It seems curious that a carb problem would only cause a problem in the #1 cylinder....<br /><br />I already swapped coil and wires, and the problem did NOT move.<br /><br />Carbs were professionally rebuilt less than two years ago.<br /><br />I can pull the #1 plug wire (when it's running well), attach it to a grounded plug, and see and hear a nice hot blue spark. When I do the same thing when it's not running well, the spark is audiably softer, and the spark is more of a yellowish color (in #1 cyl only).<br /><br />Plugs are the surface gap type (Champion UL 77-V). I bought them three months ago from a dealer, and they are the exact same plugs recommended by my origional 1975 Johnson service manual. I should also add that I pull the plugs after every run and cleam them with carb cleaner and an electric toothbrush. I might try to swith plugs themselves with another cylinder to see if the problem moves, but I have yet to read in any posts that one bad spark plug caused a problem like this.<br /><br />I guess I could try to spray some premix in to the carbs to see if the misfire goes away, but It seem apparent to me that it is a spark problem....

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

fseventy, check the connection at the spark plug boot/cover for rust. I just checked mine because I have an almost identical problem to yours with my 1974 135 HP Evinrude and there was considerable rust on the connectors for the #1 and #2 cylinders.

 

[dafox99]

Re: 1975 Johnson 135 weak spark in #1

For what it's worth, I was a boat mechanic back in '75, and we found those surface gaps could foul easily if you idle or troll much. There is no visible indicator, but it simply stops firing well after running very long at low speed. I'd swap plugs just to double-check

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

Interesting thoughts from both kevin88 and davef. <br />I also took a small pipe cleaner to all of the boot ends, crimped the ends tighter with a pair of pliers, and I add a small dab of dielectric grease to the connector of each spark plug after I reinstall them. Remember, I pull and clean the plugs after every run. I origionally replaced the plugs when I started having this problem, with no change. The boat is for pleasure, so when it runs well, it's at WOT most of the time. It only idles at the dock.<br /><br />So kevin88, are you saying that cleaning the boots solved your problem? Dosen't make sense in my case because I have swapped coil/plug wires and the problem stays in the #1 cylinder.

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

Well, I'm actually looking for some more input on that. I currently have no spark at all on #1 which is very similar to your problem. I suspect that the rusty boot may have fried an output on my power pack? Anyone have an answer on this? Is this possible?

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

fseventy, I have just found the root cause of my problem which was similar to yours so I have a test that I can recommend that can be done without turning the motor over. If you have a multimeter (ohmmeter) connect one lead to any of the 4 coil output terminals on the power pack and with the other test for resistance at each one of the spark plug connectors. A good coil will measure about 2K Ohm in resistance. A bad coil will be considerably higher. With a higher reading the coil will still spark (weakly)causing the motor to idle rough, dog out, and not reach top end. This will eventually feed back into your power pack and burn it up as well. I have learned this the hard way. And now I'm off to buy a new coil and another new power pack.

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

kevin88, if the power pack is "burned out", wouldn't this problem be constant rather than intermittent like mine is? I probably forgot to mention that I have been able to take the boat out and have it run great for 4-5 hours (multiple trips) before this problem pops up again.

 

[dafox99]

Re: 1975 Johnson 135 weak spark in #1

Hmmm. I've seen low battery voltage make that era of power pack act flakey (as well as a bad ground). Doesn't sound like that is the issue. Also, a cracked coil will fail more often as they get hot, but I think you've already checked this.

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

fseventy. The part I failed to mention I guess is that the common symptoms were obviously before that output to the power pack finally went. I now only have 3 working cylinders and the engine won't rev above 2500 RPM with a load on it.

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

Just to further my assertion, I have also had my boat run great for hours and then something kicked out and I couldn't get more then the stated 2500 RPM. I figure it was a broken wire inside the coil that was making contact intermittently. When it would make contact the motor would run great. I have ran my motor in the driveway all the way to 5200 RPM at WOT and then towed it 15 minutes to the lake and couldn't get 2500 out of it. That's when I found the spark problem.<br />I'm just trying to help you avoid burning your power pack like I did..

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

I was told by a reliable marine mechanic that the broken wire inside the coil caused all that energy to feed back into the power pack because it had nowhere else to go. And after burning 2 power packs in the matter of just 3 weeks time I'm not going to question him.

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

so kevin88, it sounds like you are suggesting that my power pack is still good, but rather the problem is with a coil? If so, that still does not make sense as I have switched #1 and #2 coils, and the problem stays in the #1 cylinder. I guess I'm still not sure what you are trying to share with me. I should have time this Tuesday to check resistance across the coils to see what is going on there. I will also try to run the various tests of the power pack, etc... Thanks for sharing what you are learning.

 

[kevin88]

Re: 1975 Johnson 135 weak spark in #1

Remember because this was only an intermittent problem it also fooled me. I also switched the #1 and #3 coils and had the spark problem stay with the #1 cylinder. If you are checking for spark with a timing light make sure your pickup isn't getting signal from one of the other plug wires, etc. I had no spark at all for a long time before I knew it due to that. It was then that I realized that the #1 output on the power pack was bad as well as whatever caused it to blow.

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

Just checked the resistance in each coil, and they were all around 2.2K Ohms. At this point I'm assuming it's the power pack, and since I don't have a "Neon Test Fixture" to test the other components, I'm going to keep my coils and fork out the $$ for a new power pack. <br /><br />Trying to diagnose a 30 yr old outboard is turning out to be very difficult even with a manual and help from you guys. Hopefully a power pack will fix the issues and it will be smooth boating for a long time.<br /><br />Thanks.

 

[fseventy]

Re: 1975 Johnson 135 weak spark in #1

Well I know that I have abandoned posts in the past, but in this case I took me awhile to save up the money to buy parts to hopefully fix this engine. I ended up buying a new power pack and recitfier. Took the boat 1st time tis year and it ran great. No stumbling problems at all. After reading other posts, now I'm worried that it was the coils or possibly other ignition parts that caused the pack to fail. Ugghhh. what a decision. DO I buy 4 new coils as a prevenative measure now, or 4 coils and a power pack later.....