1957 johnson 7.5 hp AD-11 fire on one cylinder

[JimVmd]

Newbie here, find good info, but need help. I'm no electronic engineer, and my VOM meter is foreign and not utilized much.

Anyways, got spark in lower, not upper.

So, I do the coil checks, and though it has two differing aftermarket, both appear in good shape. Primary checks, and I get some resistance on both secondary, I think. I hit ground on the coil, and end of each spark plug boot. running meter at 20K ohm, shows something like 4.3 display on one coil (a black one) and 3.6 on the green one (like sierra coil). The green one is on the upper bad. No spark using tester on upper, so it is not a case of bad plug.

OK experts, tell me what to do. Am I hitting the right points on the probe to test secondary coil? Do I have a simple spark plug wire short? Are the reading telling me something I don't understand?

In a "go-figure" state, gotta be an easy solution, just don't care to be in a replace all stuff position, but I can I guess. Points look good, gapped, condensers are just that, conns are tight.

Coil suspect I think.

 

[HighTrim]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Clean the points and reset. Run wet/dry through them many times. DIp paper stock in acetone and run that through to clean. Set to 020

 

[cajuncook1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Your going to need to inspect your point, condenser and coils. They are located under the flywheel. Hopefully all you need to do is clean and regap your points and you might be in business. Still check your coils and condensers and plug wires.


Here is how to pop your flywheel off and it gives you information about re-torquing you flywheel nut.

How to Change Coils and set points on old OMC's?/ 294072


Here are two link to show you how to test your coils and condensers.

How to test a coil in an antique outboard engine - YouTube

Antique Outboards and all about condensers - YouTube




How to replace your coils, points and condenser. Please take digital pictures as you go, so it will help you return everything back in the right order. Keep cheap zip lock bags available to put your parts in so you don't lose them. They are small.

If your coils are good, but your points and or condensers are bad, then you can certainly order a set of points and condenser here from iboats. Easy breezy.

Here is some information I put together for a guy on another forum, but the information should help you out just the same.

Here is a diagram of a generic OMC (Johnson/Evinrudle/Gale) ignition assembly. You will have to remove the coil designated for the top cylinder and put the oil wicker in. It should be already be coated with a very light oil. (not grease). The purpose of the oil wicker is to lightly lubricate the outside riding surface of the cam so the point shoes do not prematurely wear. If you look at the points they have little shoes that ride along the cam. Please make sure the (breaker)points cam is on the correct side or the ignition will be out of timing. It should have the word [highlight]top[/highlight] machine written on the side facing up.

FYI: You can only set(gap) one set of points at a time. Put the flywheel nut back on(turn with a wrench or ratchet clockwise) to allow you turn the crankshaft. (Please remove both spark plugs to make it easier to turn the crankshaft and prevent accidental starting)

You gap the point to 0.020 when the point shoes is at the top(high point of the cam). It should have a mark along with the word top. Then you will turn clockwise to the next set of point 180 degrees and set those points the same way. You will notice that the point of the previous set will be closed and when you come around again they will open up. *** When they are open no current is allow through. This is how you set your timing with the points.***

When you go to set the point's gap. Very gently snug the anchor screw, then adjust the gap with adjusting screw and the feeler gauge until the feeler gauge is sliding through with slight resistance only. Then tighten the anchor screw. Repeat procedure with second set of points. Please make sure your hands are clean and the feeler gauge is clean, because oil on the points can foul them up and create resistance....poor or no no spark. ALways use a spark check to evaluate spark. It should jump minimum 1/4 inch. Blue sharp snappy spark.

Here is a picture of a spark check...Cheap $6

Here is a picture of how to tell which wire is going to the correct cylinder. Thanks to Garry for providing the picture on other post.

If your using the existing wires then cut about 1/4 inch of end going the coil, so you have clean un-oxidized copper contacting the spiking in the coil. Twist the end of the spark plug wire onto the coil spike. If you have replaced the wires, make sure they are 7mm copper metal core and not the automobile stuff.

***** Please make sure two things*****

1.) Make sure all the wires are tucked away under the flywheel and not rubbing up against the cam or crank, because with will eventually get damage and create a short, then no spark!!

2.) Make sure the coil heels (ends) are evenly lined up with the mounting boss.

Here are some pictures. (Compliments of JBJennings..nice fella)

Lining up the coil heel with the mounting boss prevent damage of the coils and the flywheel magnet, prevent rubbing as the flywheel turns.

[highlight]*** Make sure the throttle is advanced to that start position***[/highlight]


Here is another picture that Garry (thanks Garry!!) supplied on another post with some modification.

Both diagrams, should answer your questions.

 

[cajuncook1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Not professional videos, but they can help guide you through ignition diagnostics and repair. The motor in the video is a 1968 Johnson 6hp.

I posted this to help another member, it may help you with the ignition.






Hopefully will give you a visual and help you some.

Evinrude Gale and Johnson ignition video 1

Evinrude Gale and Johnson ignition video 1 - YouTube


Evinrude Gale and Johnson ignition video 2

Evinrude Gale and Johnson ignition video 2 - YouTube


Evinrude Gale and Johnson ignition video 3

Evinrude Gale and Johnson ignition video 3 - YouTube


Evinrude Gale and Johnson ignition video 4

Evinrude Gale and Johnson ignition video 4 - YouTube


Evinrude Gale and Johnson ignition video 5

Evinrude Gale and Johnson ignition video 5 - YouTube


Evinrude Gale and Johnson ignition video 6

Evinrude Gale and Johnson ignition video 6 - YouTube


Evinrude Gale and Johnson ignition video 7

Evinrude Gale and Johnson ignition video 7 - YouTube



Sorry the camera and video edit software was not all that great. It is very hard to see the spark when I am checking with the spark checker, but in the end I get both set of spark plugs to fire even though you may not be see them. Anyway, I think you will get a good idea how to work on OMC ignition from 1950 to 1973.

Hope it helps anyway. Oh, sorry about the caption that the video edit was not activated so it is a little distracting.

Cheers, hope y'all have fun working on old outboards!!!

 

[JimVmd]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Thanks all, I have read and seen most of these suggestions and I should have gotten out here earlier with my question and would have saved myself some time finding links.
I think I may have a motor worthy of fixing the ignition, sooner or later I'll figure what I need to replace. In the meantime, I was wondering what compression these '55-'58 AD- models should have.
I was looking around, and didn't see it jumping out. I "dry-tested" (no oil, no knowledge of history on mine - ebay buy), and got 62 and 64 readings.
Is this worth continuing with? They were close, but I don't know if they should be at 80-90 lbs or whatever. I should buy a service manual (I will if this is a runner).
Can anyone tell me on my 1957 7.5 h.p. AD-11 if this is a workable engine worth ignition part(s) and carb kit based on initial compression?

Thank you.

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

No.

 

[Steve A W]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Jim
If You can get spark without putting much money in it, get it running then run SeaFoam in the gas/oil mix.
This will clean carbon from the rings and combustion chamber.
After some running check the compression again.
The first classic OMC I brought back from the dead was a 1955 Johnson 5.5hp and had compression in the low 60s.
After a season of SeaFoam in the fuel its up to mid 80s and runs great.
Good luck with Your motor.

Steve A W

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Maybe this would help: Parts should cost in the neighborhood of $125 to $145. If you end up with a motor that still won't fit your needs, most of the parts (maybe all) can be reused in a similar motor. Can't say what your expectations are, or course, or what additional money you want to spend. Good luck -- nice motors (I have a few of them.)

 

[HighTrim]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

The 7.5 are not high compression motors by any means. The fact that they are equal would be good enough to proceed. As mentioned, once running give a heavy dose of seafoam. Not all meters read the same either. Im never worried about compession numbers like that on a 7.5. Might need head gasket and the head dressed as another alternative say. Doubt you have any major surgery to worrry about here.

 

[JimVmd]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Root cause determined. The top cylinder point set lock-down screw is screw-doodled. I set the points again (with new ignition plug wires installed) and got fire in the suspect hole! Success, until I turned a few times more and lost it. Found the point set lockdown screw never really locks down on top cyl offender. Hole stripped, what a common occurrence older folks like me experience.
I need a new plate or some powerful loctite. Pills will not remedy.
Is the plate available? Lots off parts available, but I may need to dive deeper on a new plate with good hole.
Suggestions please.
Reason for fine motor with loss-cause problem via ebay.
Thanks,
JimV in Maryland.

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

Jim -- I think I would try a slightly larger machine screw and see if you can get it to fit, or tap the hole and then replace it with a larger screw. It would be nice if Loctite (or a pill!) would do it, but probably not -- but might be worth a try (Loctite or a dab of epoxy, maybe). There's probably no harm in getting creative. The obvious solution is to replace the plate, but unless you have a box full of '50s parts from other projects, that can be tough.

Off the topic a bit (but not entirely), the Old Bay Chapter of the Antique Outboard Club is located north of Baltimore, and might be a group you would like to join. Unfortunately, it will cost $50 for a two year membership in AOMCI plus a few bucks for membership in the local chapter. But this gives you a source for parts. You can also go to the website (AOMCI.org) and post a request for free (membership not required).

 

[Crosbyman]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

no offence to the high compression folks but my 7.5 was around low 70's

converted it to pump, refurbished electricals, impeller and carb kitted the oldie

Ran it 24/1 on Amsoil syntec oil
Super smooth.... trolling along side my 75 ETEC last summer. Starts easy and purrs Paid $75 plus parts

I expect my winter rebirth of a 5.5hp mdl 5512 Evinrude to be the same ....compression in high 60's ( will seafoam it next Spring)

Motor had upper cyl. stuck but it loosed up nicely. Aside from surface scratches I think it was just a sleeping beauty with originall (old) cracked coils and a dirty carb. Paid $125 plus parts

just my experience.....with oldies 0 compression is bad.... anything over 60 is hope

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

pretty much agree with Crosbyman, but add that the 7 1/2 (uniquely) should be run at 16:1 by the book -- though admittedly would probably run for another lifetime on 24:1, like the other '57s (smaller and larger). These motors are pretty durable. I do try to use TCW-3 Bombardier or Quicksilver 2-cycle.

 

[HighTrim]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

I do have spare mag plates if loc tite does not work.

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

There you go, Jim! In the meantime, thinking you might just try another screw from your supply of oldies. Just try for something that will grip (same size even). Diff. thread count, something. Maybe in combination with Loctite. Not really any serious stress on the anchor screw, but on the other hand want it to stay tight -- could get pretty tired of removing flywheel.

(ah, but maybe you are doing this through the adj hole on top of the f.wheel? might work.)

 

[JimVmd]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

I do have spare mag plates if loc tite does not work.

Thanks for the note HighTrim. I do have interest in purchase of a good plate. Mine is marked p/n 580210-1. I do not know if that is the correct plate, as I have no history on this engine. If you have a part number manual, perhaps we can start with confirmation of this current installed.

If you confirm a good/right plate is available, shoot me a note about your price on PM. Thank you.

And to oldboat1, thanks for all your help and information throughout this string. Greatly appreciate everyone's returns, and for someone starting out new with the old, it has been very beneficial.

More on the larger screw. Evidently that repair has already been once tried. The screw on the bad set is noticeable larger in diam. I also see on the underside where the previous repairman grounded of the end of this larger/longer screw to get it flush on the backside of the plate. Not leaving me with too many choices other than to locate the correct plate and replace.

 

[oldboat1]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

yup. been there. all fun though (well, sometimes more than others). Best.

 

[HighTrim]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

I think my collection of 50s OMCS mag plates tops 100, so Im sure I have one

You should see my boxes of carbs. Im proud of them, my wife says Im an idiot. I think she is jealous.

 

[JimVmd]

Re: 1957 johnson 7.5 hp AD-11 fire on one cylinder

The stator plate was replaced, and good spark obtained. Thanks all, good references in this string. JimV