1971 Johnson 25hp (No Spark in Top Cylinder)

[Vapour1ze]

Just got this locally today from a pawn shop. Carb is superior clean, I took all apart, looks amazing. Didn't even check for spark like I should have. Has good compression in both cylinders. I also bought 2 new spark plugs, Champion J8C's correct me if those are wrong thats what I was referred to.

Then the problem came upon me bottom cylinder good spark with both spark plugs, top cylinder, no spark with eathier spark plug, is this coils ? or what ? Thank You!

 

[ultra353]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Dirty or corroded points are the most common cause. Pull the flywheel and inspect all components. Tune-up kit is $20-30. J4c for normal running or J6c if your going to troll with it.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Ok, I got to the point of getting the flywheel off and I don't have a 3 prong puller thing, so I gotta rent one from AutoZone, so until then do I need the tune up kit or not? And also what am I looking for once the flywheel is off, it says on the flywheel set points are .020 or something like that.... Where do I go from here? Thank You

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

 

[Daviet]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

I would remove the flywheel first, inspect the coils for cracks, replace if any visual cracks, clean and reset the points to .020. The front coil controls the top cylinder. Reinstall flywheel and recheck spark.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

and is this the tuneup kit you were talking about? http://www.iboats.com/mall/partfind...gd_poid=111574&gd_row=18&**********=219842408

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

How do I reset the points what do I need and how do I do it?

 

[Daviet]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Look on the cam that opens the points, sometimes there is a spot that says "top", if not just use the highest point on the cam. Rotate the crank until the rubbing block on a set of points is in position on the highest point of the cam and set them to .020, rotate the cam lobe to the other set of points and repete.
You use a screw driver to loosen the screw that holds the points in position.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Ok onto the next problem, got the flywheel off, got to the points, turned the flywheel until it was at the highest point , which is what I thought was right before the flywheel got easy to turn when the pistons fall back down or whatever, I adjusted the points which were very incorrect and not at .020 I adjusted them to .020 thinking everything is going to work woohooo I'm on my way, because the coils aren't cracked, nope I put everything back together and now I get no spark on eathier cylinder where before the bottom worked and the top didnt, now neither work..... Should I readjust or should I buy the Tune Up kit for 17.99??

Pictures below of coils, which look brand new to me,

 

[Monte1961]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

From the pictures I can see it's pretty clean, so If you have good compression, this thing should run quite well. Here is what I think. Did you clean contacts? Was shear-pin installed? Go back and double check that points are set correctly. If you look where the shear-pin sets in crankshaft, that's your highest point on the cam. This is where you want the rub block on the points to be. Now set them one at a time to where .020" feeler gauge just passes through, but .022" will not. Make sure points are tight and clean by using break clean or some type of electrical cleaner. You get the idea!. Want no oil residue of any kind. Take shear-pin and aline it paralleled with crankshaft. Carefully set flywheel in place. Install washer and nut. Only tighten nut enough to keep flywheel in place. Now remove spark plugs, making sure your in neutral and kill switch is off or bypassed, and check for spark. If good, tighten Flywheel nut to spects, if not, well obviously something isn't right. Good luck and let us know.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Thank you very much for that reply, I should have read that sooner, however I took off the points and the coils just to get a closer look and I took a picture, so basically I shouldn't buy the tune up? Just try to clean everything and set everything and try again? I still am not sure what you mean by align the shear pin with the crank shaft, sorry I'm very noob with outboards, I can keep up but I need a step 1 step 2 step 3 or pictures, get what I'm saying? But anyway thank you so much that reply helped a lot, just the whole aligning this to get the highest point I'm unsure, about also one of the points when adjusting wouldnt adjust correctly, i would turn the screw for the move in or out and the point would just stay put, does this mean I need to buy new points or no? Sorry its hard to explain in a post, but its my 2 cents, heres a picture of everything out ,

Thanks again.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

i just figured because coils had some bad looking wires, and the points had adjusting problems kind of, maybe it was time for new coils and new points and then go back to setting just to make sure, i just still am not positive about the TOP POINT OF THE CRANKSHAFT, thats my only issue...

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

bump

 

[Daviet]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Look at the cam around the crankshaft, what does say on it? Or better yet, take a picture so that we can read it.

 

[Monte1961]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Ok lets see if this will help you? Where the points ride on the crankshaft, that's called the points cam. Take your spark plugs out just so you can spin the engine over easier and for no other reason at this time. Have motor in gear, foreword or reverse doesn't matter, have your wife son or daughter or a friend turn the prop by hand. While you watch the points and crankshaft. Now as you see the points begin to open on the cam/crankshaft, you can see where it looks like it's oval shaped. Thats the cam.! Now where the cam is at it's highest point in relation to points (Widest opening), this is where you adjust the point/s gap. Try and not over think it. I'll try and find a pic or two to help with this. But I can tell you that when you see this happening with your own eyes, It will make total sense to you. Good luck Vapor and post back.

 

[Daviet]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Put the crankshaft nut back on and use a wrench to turn the engine over, you can control it better.

 

[Monte1961]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

I'll wake up sooner or later Daviet! Should have said that, Now that I am confused!... lol

 

[Daviet]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

To be honest , many years ago I did it that way. Then I figured that if I took an old nut and welded a rod across it I could use it like a wrench, worked a lot better.

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

Ok, soooooo thank you everyone for the help, motor is running got to take it out today, and runs awesome wide open, but now if I set and let it idle it runs very weird, idles for about 2 seconds then hear a loud CLUNK then idles again for a few seconds then another CLUNK but nothing when its wide open, see the videos I attached please, they show it very well. Thanks !

[video]http://www.thenerdforce.com/videos/boat1.MOV[/video]
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[video]http://www.thenerdforce.com/videos/boat2.MOV[/video]

 

[Vapour1ze]

Re: 1971 Johnson 25hp (No Spark in Top Cylinder)

YouTube links,,,, (easier)

idling - http://www.youtube.com/watch?v=RGaQQ7CQq6c

wide open - http://www.youtube.com/watch?v=6uIJ6HeSlsg