IH 560 backfire miss

Anonymous-0 · Jan 2, 2012

Just had the hydro overhauled on the 560, then the one coil went out (switched to a 12V IH coil two years ago, not sure why it went out so soon but think the switch was left on and voltage to coil overheated it) switched coil with a generic 12V automotive coil from auto parts store (only place open on Sunday) Ran good, cleared snow for a couple hours. Anyway, went to start a few days later and missing/backfiring. Checked plug wires, firing order and ended up rotating dist. a couple degrees and it ran good. If I restart it within a few hours it runs good, but overnight and next day same thing, end up rotating it back. I removed the dist and cleaned, checked springs. Same thins.
Any Ideas?
Thank you,
Craig

Janicholson · Jan 2, 2012

Possible bad plug wires. If wire is inside, (wound magnetic suppression, or solid stranded wire, the issue is conductivity. yes or no. If carbon suppression wires, 5000 to 7000 ohms per foot of length. The distributor cam bushing could also be causing issues with timing No more than .001" looseness. The final component to check is condensation in the distributor cap causing mis directed spark. Use a blow drier, then silicone spray.
If that still is no fix, water in the fuel could make that symptom. (not likely if you are using 10% Ethanol fuel. Jim

old · Jan 2, 2012

Have you checked and or replaced the points?? A lot of times when a coil goes out it shorts out inside and that in turn puts a heavy load on the points and that in turn burns them and can even get hot enough that the point arm bends and then you have the timing and dwell way off

Anonymous-0 · Jan 2, 2012

Thanks Jim,

New plug wires, less than 25 hours but I will check them. It is odd becuase i can make it run with adjusting the dist. a couple degrees and it runs at low, med, high just fine. Let her cool down over night and i have to adjust it again.
No moisture, have cleaned it with elecrical parts cleaner and silicone a couple times in the past couple days. New dist cap, coil, cond., points also.
Thanks,

Craigswanson · Jan 2, 2012

In the past 25 hours of run time (dont use it much) I put on new plug and dist wires, new plugs, new dist cap. With the hydro rebuild just last month I had new points and condenser put in. I took the points out, cleaned them up and adjusted gap to .021".
I believe the coil that was a year or two old went bad because the switch was left on and it overheated, do you think that could have ruined the new points and condenser?

old · Jan 2, 2012

Well with the key left on and that in turn burns out the coil think about it the points are the operating switch for the spark system so yes your new points could well be burned up and the arm can even be warped by heat which I know for a fact happened when the key was left on

Janicholson · Jan 2, 2012

An intake manifold leak (internal or external) can make the system run as described. When warned up it curves enough to seal pretty well, When cold it pulls away and leaks. Just thinking out loud. Does the choke make any difference? The point gap is supposed to be .020" on a high point of the cam.
Do check the distributor shaft wear. Jim

IH 560 backfire miss

Anonymous-0

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