Ignition Troubleshooting

[Bullnose Gator]

Hijack away, maybe I'll learn something.  Also, I'd like to learn how to use one of those testing meters you tested your repaired coil with.  That seems like it would be a worthwhile test to run on mine once i pull it out.

[grumpin]

Here’s a how to I googled and found, many more out there.

A multimeter is a very good tool to have. The one in the post is fairly inexpensive from Harbor Freight. I recently fixed up an old favorite Craftsman that I’ve had for years. I also keep a cheap analog (needle that swings) around. Sometimes when I’m just looking for voltage or continuity and all I need to see is movement, I like them.

https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/all

[Bullnose Gator]

Great, I'll be picking one up thanks. Another question, how do I remove the black ninja star looking thing from the distributor shaft?

[Gary Lewis]

Sparkfun is a great outfit, so I'm sure their how-to is a good one.

And I agree that a cheap DVM is plenty.  But a meter with a needle sure would be handy!

[Gary Lewis]

You pry up on it gently.  It is held with a roll pin in a slot that provides pressure, and sometimes the shaft can get rusty, so a bit of oil can help.  But only a bit.  And did I say GENTLY?

[Bullnose Gator]

I'm not sure that I can get anything down in there to apply leverage to pry. How would you go at it?

[Gary Lewis]

I've done it with small screwdrivers, just prying in one place a bit then in another place and walking it up, slowly.

But the best thing I've used is a small 2-jaw gear puller.  Put a piece of metal across the top of the shaft to press against and bring it up slowly.  And if you don't have one you may be able to "rent" one from your local parts store.  They usually charge you the price of the tool and then give it back when you return it.

[Bullnose Gator]

That sounds perfect. Heading to harbor freight. Tonight's grocery list: 1) multimeter 2) 2 jaw puller.  Let me know if I'm forgetting eggs & milk or anything else.

[Gary Lewis]

LOL!  Looks like my kind of shopping.

You could consider a 3-jaw puller, but they are usually larger and you want something pretty small.  Most pullers allow you to turn the jaws around for inside or outside work, and some of them have two or more slots on the arm to install the jaw, allowing you to make it larger or smaller.

[grumpin]

I used a 3 jaw puller. Sometimes though I could get it off by hand.

[Bullnose Gator]

I finally got the pickup coil replaced, but the same symptoms persist.  Since this seems to have originated with the ICM, I guess I'll go back to messing with that again, but I appreciate any other guesses yall might have.  Also, I don't know if it is in my head, but it seems like when I put the rotor back in today it wasn't pointing the same way it was originally.  Any chance I turned the shaft while getting the gear out?  If so, what issues would that cause?  I can get it to turn over, but after idling roughly for a bit it stalls.  

[Gary Lewis]

I don't know about turning the shaft, but I saw the writeup below in the 1980 factory shop manual the other day and its discussion about the alignment of one of the spokes of the armature being in alignment with the stator might be applicable.  I would see if the spoke and the stator line up.  And, if the rotor aligns with #1's terminal at the same time - when the timing mark for #1 is at TDC.

Oh, and another thought.  How old is the damper?  I've seen the outer ring on them slip such that the timing mark was a long way from where it was supposed to be.  So if the damper isn't new you might want to find TDC and see if the mark aligns.  You may have the timing way off.

[Bullnose Gator]

I don't know anything about how timing works, or even what a damper is, but I'll google around and try to trouble shoot what you're suggesting, thanks.  Well, I will after I find a replacement roll pin for the distributor gear.  I took it back off because I forgot to put the pickup coil spring clip back in when I put everything back together and fired it up.  Then it fell out of my magnetic holder somehow

I've googled the pin's part number, but can't find any specific specs on it.  Any idea of it's dimensions?

[Gary Lewis]

What is the pin's part number?  Maybe I can find it.

As for the damper, that is the thing on the end of the crankshaft, on the very front.  It is made in two parts - the inner hub and the outer ring, and there's rubber between them.  When the rubber gets old it can lose its grip on the metal parts and the outer ring can slip in relationship to the inner hub.  Which means your timing marks are wrong.

So you find top dead center (TDC) on the compression stroke and check to see if the TDC mark is aligned with the pointer.  Again, this has to be on the compression stroke of the engine, and that can be found by placing your thumb over the sparkplug hole and spinning the engine over with the starter.  (Make sure it is out of gear and everything is clear of the fan.)  When it comes up on TDC it'll blow your thumb away from the engine.  You won't be able to get the engine stopped in time, but you can back up a turn or so and get it.

There are lots of ways of finding TDC, but these are the main two:

Piston Stop: You can buy a device that screws into the sparkplug hole and stops the piston.  You turn the engine over BY HAND very gently and bring it up against the stop.  Mark the damper where the pointer is pointing.  Rotate the engine back the other way, very gently, up against the stop, and mark the damper at the pointer.  Half way between the two is TDC.  So if you remove the stop and position the engine there the timing pointer should be pointing at TDC if the damper is good.

 

Straw: Or, you can insert something soft, like a soda straw, through the sparkplug hole and turn the engine over gently and note where the straw is sticking out the farthest.  That is roughly TDC.  And "roughly" might be good enough to check to see if the damper has slipped.

[Bullnose Gator]

The part number is 305015-s (NN-84-G), per the illustration I found here:

https://www.garysgaragemahal.com/distributors.html

[Gary Lewis]

Yep, I found that.

And from the Standard & Utility Parts Catalog (Documentation/Reference/Standard & Utility Parts Catalog):

[Bullnose Gator]

Perfect, thanks.  Cranking by hand is done by using a ratchet on the front of the engine, is that right?

[Gary Lewis]

Yes. And clockwise.

[Bullnose Gator]

O'rielly's has a pack of roll pins in stock that includes a 3/32" x 1/2" do you think i could use it even if it's a little long?

[Gary Lewis]

I think you can.  But you don't want the pin to come close to the stator, so any excess should probably point down - unless it'll hit something.