56 Johnson Javelin one cylinder not working

[oldboat1]

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[oldboat1]

Jimmbo, you said " the access port for the points and coil inspection is plainly visible" but I guess I'm bleary eyed tonight because I can't see any access port. Here's a pic of the top of the flywheel. Where would I find the access port so I can visually inspect?

Take out the three hex bolts in the device at the top, then the three short screws holding the triangular plate underneath. Look through the hole under the plate -- check for cracked coils, which you would need to replace. (You can also adjust the points through that opening.)

If you can clean up and use the connectors on the ends of the wires, you will save some work. A little carb cleaner and some sandpaper should do it (maybe a wire brush). Those appear to be the style that attach under the terminal on top of the plug -- would screw off the terminal, put the wire in place, then screw the terminal back into place. Later plug wires have connectors in a boot, which I'm sure you know -- the older style is actually simpler. The wires have a solid core, either wound strands or solid copper -- as opposed to carbon core automotive wires.

If cleaning up the ends works for you -- gives you connectivity -- I would go with that. You can always go back and replace the wires. On the other hand, if you have to replace coils, you might want to just get some solid core wires and the newer boots and connectors (standard 7mm with a solid copper core). Do it all at once.

 

[SteveVT]

No spark check yet? Seems like that's where to start before buying all new ignition parts, pulling the flywheel, etc.

I say this, having personally bought all new parts, pulling the flywheel, etc., LOL.

Sometimes you compound a problem...... I did, when the replacement condenser wire rubbed against the flywheel and created an intermittent spark.

Anyway, a spark test wouldn't hurt even now unless things are so far apart that it isn't possible to do.

 

[KathyD19]

Steve, no I hadn't done that yet. Honestly I didn't know how so I'm googling it.:facepalm:
They are brand new spark plugs so I assumed they worked. I also switched the top and bottom plugs out since the top cylinder was working ok but perhaps doing a spark test is actually testing more than just how well my plugs work? This electrical stuff is no for me. I don't have a boot on the lower cylinder wire right now; it split apart in my hand as I was removing it. I'm in the process of trying to remove the plate for the access point so I can view and inspect the coils, etc. I have the 3 bolts off but the single flat-blade screw is stuck good. I've soaked it in PB Blaster and WD40 all day but not getting it to budge. I don't want to strip it so I'm considering using a heat gun on it next. One step forward, one step back with this project. But I'm learning something each time so it's ok. Thanks for your input....always welcome another voice!

 

[jbuote]

Hey Kathy..

​You did do a "Cylinder Drop Test" by pulling the plug wires..
It ran on the top cyl, but not on the bottom..

​That alone says there is an ignition issue with the bottom cylinder, which you are investigating.. (plug wire, connector, coil etc... )
​I guess folks (myself included) pointing you to coils first is because in engines that old, if they weren't replaced and are factory coils, then they are bad... (more than likely.. lol)

​However...
SteveVT does make a good point.. A spark test would tell the story.. It would confirm if that cylinder is firing or not..
​
​I could be wrong, but a "Drop Test" as you've done by pulling plug wires off the spark plugs and it runs or dies is indicator #1..
​Then it becomes, "Ok, WHY does it stay running and therefore not fire" on that plug wire you pulled off. (to paraphrase.. )

​There, it could be plug wire, coil, points, condensers etc... That's where the troubleshooting comes in...
​Coils are a common issue in an engine the age you have.. (if never replaced..)

​You've identified corrosion on the plug wire, and some other things, so as newbie myself, I do believe you are on the right track already...
​I'd be willing to bet a spark gap test would also show that the bottom cylinder has weak or no spark at this point..

​The spark gap test shows if the ignition system is capable of providing spark across the small gap of the spark plug..
​It does this by expanding the gap to say 3/8 inch in open air, under no compression by pistons at all..
If spark can jump that gap in open air, with no compression by the cylinder, and it's a bright blue spark with a crisp "SNAP", then it can jump the .030 gap when under compression in the cylinder.
​Compression affects how the spark will work..

​If the spark gap test fails (spark is orange, or no crisp "SNAP"), then you troubleshoot the ignition system to find out why you aren't getting appropriate spark as tested..

​All specs I stated above are just generalized, and I in no way mean they are applicable to your engine..
​Truth is, I don't know the open air spark gap needed to test your particular engine..
Just the theory behind it.. lol

​All in all, I still think you're on the right track already, but just hoping that helps clarify what a "Spark Gap Test" does... (As I understand it... )

For what it's worth..

 

[SteveVT]

Yes a spark test checks all of the ignition components. If there's a healthy spark, you know the magnetos, at least, are good, that the points are opening at approximately the right time, and the plug wires are not open or shorting the spark, and the condenser is good.

It doesn't mean things are perfect -- the timing might be off so points might need adjustment, for instance. Or they may be getting pitted. But fairly likely you don't have to send for new magnetos.

A spark test is just a matter of looking at the spark. There are several ways to do that, but basically they all involve having one piece of metal connected to the spark plug wire, and another connected to the ground, and an air gap between them.

The gap recommended here to me and in several posts for these motors is 5/16". This gap can be between two finishing nails in a board.

Or it could be an old spark plug with the electrodes bent to that gap with a plug wire on it, and the base grounded to something metal on the engine.

It can be hard to see the spark in bright daylight, unless something dark is behind it.

Don't get shocked by holding the plug or anything metal (like pliers) on the plug to ground it against the engine.

Don't do this where there is any free gasoline or vapors present in the vicinity.

If there is no spark, then the question is -- why, since anything then in the ignition system could be at fault. Magneto, condenser, points, or plug wire.

Through a process of elimination, you narrow that down.

You can individually swap parts to narrow it down, if you have one cylinder that sparks and the other does not.

Hope that explains the most general part anyway.

 

[SteveVT]

jboute, posts crossed.....hadn't seen yours when I wrote mine.

 

[KathyD19]

Wow! Thank you for all of that info. I have a deep seated fear of getting shocked so I am going to have to push myself to do the spark test. We've had nothing but rain here this weekend but it's supposed to be nice tomorrow so I can pull the boat out of the garage and get the motor in a barrel. Maybe I can bribe (trick) my husband into doing the spark test for me. :lol:

 

[jbuote]

If you're going to do an open air spark gap test, there are "Adjustable Spark Gap" testers available a most local auto parts stores.. Around 8-10 bucks..
​They are encased on 3 sides in plastic, and are adjustable.. An alligator clip on one end to connect to ground (engine block) and a post on the other end to attach plug wire (boot or connector)...
​
​With that, it's pretty much hands off, so no risk of shock.. lol..
(Unless you are curious if hubby gets shocked or not.. )

Always a good tool to have in your toolbox, but again.. Just informational.... Still think you're on the right track already with other advice than mine.. lol...

 

[KathyD19]

Sold! Heading to Harbor Freight tomorrow for that little gadget as well as a flywheel puller (just in case)

 

[jbuote]

Just be sure that you set the tester at the right open air gap if you test that way..

SteveVT indicated 5/16".. I'd go with his figure because I have no idea.. Sounds like he does.. LOL..
Setting it to the correct open air gap is important to get accurate results.
​If that's what you do..

 

[SteveVT]

Nope, 5/16" not my own preference, just passing it on from racerone (and others here). That actually seems like a pretty wide gap, to me, but I'll go with the majority opinion.

More than likely, you won't get a spark at all on that misfiring cylinder.

Just to let you know in advance, if you replace the magneto, condenser, and have the points set right, replace the spark wire, and STILL have a problem, here's another possibility, at least on my own engine.... (Evinrude 1963 Lark V 40hp):

There was a safety system that intentionally blanked out the spark on the lower cylinder at certain conditions of engine vacuum and low RPM. It was intended to prevent over-reving from throttle runaway. It involved a wire from the vacuum sender, and a throttle position sensing safety switch mounted to the engine. This safety switch on mine was held by two screws -- one of which was missing, allowing it to ride out of position.

I'm not saying you should concern yourself about this -- your present problem is more likely to be something normal failing in the ignition system (mag, points, condenser, plug wires), BUT if all else fails look to see in your manual if your engine has anything like what I found on mine. Maybe your engine doesn't even have that feature, but if it does, and nothing else seems to be wrong, it does explain on my engine why one cylinder might be firing and the other not. In fact, under certain conditions, that's what it is designed to do.

 

[racerone]

Some will argue.-------The wonderfully simple universal magneto can develop up to 28,000 volts.-----In good condition it can jump a gap of 5/16" with ease !

 

[KathyD19]

No Title

I have all my ducks in a row to work on this on my day off tomorrow. I am still unable to get the last screw on the access plate to budge (as seen with blue arrow in pic). I have soaked it in PB Blaster and also WD40 for a couple days now with no luck. My next idea is to use a heat gun then let it cool and try it again. Other than that, I'm out of options. I'd just like to see what the coils look like so I can find out if I need to replace them. Also I found that spark gap tester jbuote told me about, will have to use that. I got a package of replacement boots/terminal sockets on Amazon that came in today but the boots are a little big and the terminals are too long...practically swallow up part of the spark plug end and don't click into place like the old metal terminal did. I decided to use my Dremmel and clean the corrosion off the old metal terminal and try to reuse it. I had to use the new boot since the old one crumbled and it's not as snug as the old one. The spark plug does give a solid click into place with the cleaned up terminal socket. A cold front came through and it's only supposed to be in the mid 40's tomorrow but I'm going to barrel test this and use the spark gap tester as well as see if my corrosion-free old terminal/boot work. If anyone knows where I can get the correct fitting replacement for the boots/terminals I'd appreciate it! I asked at my local Auto Zone and O'Reillys and they were of no help.

 

[jimmbo]

If the inspection cover won't come off, remove the flywheel, you probably would have to anyway. Then with the flywheel resting on something solid, get one of the impact screwdrivers you hit with a hammer.

 

[Willyclay]

If anyone knows where I can get the correct fitting replacement for the boots/terminals I'd appreciate it! I asked at my local Auto Zone and O'Reillys and they were of no help.

I believe the OMC/BRP p/n for one Boot&Clip is #0580339. Clip is what they call the terminal. Cannot find a Sierra p/n except for a ten-pack. Did find a Sierra p/n for 7MM marine solid core spark plug wire sold by the foot which is #18-5226. NAPA stores handle Sierra brand. FYI, my Harbor Freight flywheel puller broke on the first use and the main bolt bent so you might want to save your money. Most of the chain auto parts stores will loan specialized tools if they have the proper three-leg type you need. Good luck!

 

[KathyD19]

Great to have those part number Bill!! Thank you! The bottom dropped out on us temperature-wise here in central Illinois...down to the 40's in the day time so I haven't had the chance to barrel test the motor. It should be in the mid 50's this week so I will make an attempt before I put it away for the season. I'd really love to get this working on both cylinders before putting it up so it will be fresh and ready to go next Spring. I already bought the flywheel puller from Harbor Freight...hope I have better luck with mine than you did with yours! It was only $13.00 so I can afford that if it doesn't work. Still would prefer to get that access panel off and take a peak to see if I even need to remove the flywheel. I have to get that stubborn screw out first. Going to try the heat gun and look around for the impact screwdriver (pretty sure we have one because I remember using it on something else years ago).

 

[Willyclay]

Did find some 7MM tinned-copper spark plug wire on O'Reilly's website which I believe is equivalent to the OEM stuff and Sierra's. See the link below. Us old geezers used to ask for Packard 440 wire but now the snot-nose kids behind the parts counter just roll their eyes. ACDelco may still be making it. Stay warm!

https://www.oreillyauto.com/detail/...plug-wire---bulk-17889/plug-wire/mw11/2601650

 

[oldboat1]

I wouldn't hammer on the flywheel trying to remove the view plate. Find or buy a bladed screwdriver big enough to fit those screws without tearing them up. Take one of the screws you've removed and go out for a screwdriver to fit.

Attach a pair of vise grips at the blade of the screwdriver. Bear down hard on the screwdriver to hold it in place, and try to break the screw loose by simultaneously using the vise grips as a lever.

Additionally, you can get boots and spring clips here at iBoats e.g., http://www.iboats.com/Magneto-Group/dm/cart_id.631356365--session_id.225116946--view_id.1532255 I find the 7mm wire at the local NAPA outlet.

 

[jimmbo]

I wouldn't hammer on the flywheel trying to remove the view plate.

On reconsideration, that might not be the best idea, in theory it could weaken the flywheel magnets.
However, since you are pulling the flywheel, the inspection plate in not too important. It only allows visual inspection and adjustment of the points, without having to pull the flywheel. Replacement of any parts will require removal of flywheel

580339 is the part number I have in my parts manual, but it is 50+ years old