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MPH

Won't fire up--IT Lives

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MPH

I got this 16hp all installed and hooked up today, and it won't run at all. Saturday nite I first got it in and jumped it, poured a little gas in carb 3 times and it fired right off each time, the last time it backfired as it used up the lid of gas. Now, I have nice blue spark, 110lbs compression, sucking at the air cleaner, pressure from the muffler, gas to the carb. should run. It won't fire if I pour gas in the intake and won't even fire if I pour a little in the plug hole. Any easy way to check if the backfire threw the timing off? Tried hand turning it watching for spark with my fingure in the plug hole but didn't get any sparkAny other thoughts?Decided to go back to the shop and check the point gap, little loose on .020 so I reset. Went to check the plug and started skipping spark, then went to none at all.Finally got victory on getting it to run. Loader seems to work as should, tranny works good, has zero traction and steers like the 1937 CC Case I first learned how to run a tractor on, whatta beast.

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Thanks again for all the help.

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osenga

Well if you pull the engine. Be a good thing drop the base pan and see if the plunger is wearing down on the cam. I have seen that happen to and then they get spark off ands on. Don't ask how I know this on a old 10hp Briggs

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HubbardRA

I would try an external coil and battery setup before I would pull the engine. If it runs on that, then I would say you have a bad coil under the flywheel or the flywheel has slipped.

Remember that with an external coil the engine will run even with a slipped flywheel. This is because the points trip off the camshaft. Only the magneto is is triggered from the flywheel.

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BLT
quote:Originally posted by HubbardRA

I would try an external coil and battery setup before I would pull the engine. If it runs on that, then I would say you have a bad coil under the flywheel or the flywheel has slipped. Remember that with an external coil the engine will run even with a slipped flywheel. This is because the points trip off the camshaft. Only the magneto is is triggered from the flywheel.


id="quote">
id="quote">Wouldn't a sheared key indicate a loose flywheel nut on the test bench. Marty says that there is a geneous spark, but it it won't run.

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midnightpumpkin
quote:Originally posted by HubbardRA

I would try an external coil and battery setup before I would pull the engine. If it runs on that, then I would say you have a bad coil under the flywheel or the flywheel has slipped. Remember that with an external coil the engine will run even with a slipped flywheel. This is because the points trip off the camshaft. Only the magneto is is triggered from the flywheel.


id="quote">
id="quote">What Rod said, also what I said in your first post.You said "Went to check the plug and started skipping spark, then went to none at all."John U

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HubbardRA

Fishinwiz, Improper torque will allow key to shear and the flywheel to slip rotationally. This will move the charging position of the magneto out of synchronization with the points that fire the ignition and cause less or even no spark. The magneto can be charging, the points can be gapped and opening properly, but they are not working together to generate the spark needed to fire the ignition.

This is why I recommended trying an external coil, since they charge from the battery of the tractor and are not sensitive to a flywheel slippage. They would, however, be connected to the same points and condenser that the magneto uses so that the actual firing of the ignition would be at the same time as the magneto.

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GLPointon

Marty all this advise is great but also dont forget the very easy stuff like the condenser. I bet 8 out of 10 "no spark" issues I've had were fixed with a new condenser, Briggs engines love to eat'em...and its very easy to rule it out 1st.

also I will crank the engine without the plug to exhaust any unspent fuel in case your getting the plug wet...

otherwise it sounds like the backfire popped the FW key :o(

good luck sm01

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MPH

Since you were the first too suggest, and if I recall right from days gone by your tractors all have external coils. What type of coil do I need that I maight get at the local NAPA? Then in kooking it up I just run power to the * side and ground to the neg side??

Sheered key sounded like ir would give me the decreasing spark problem that developed yesterday so I spent 45 min pulling the engine and had it stripped down to the flywheel. The key was fine:(!, seemed like an easy fix. I had tried a condenser from the 16hp on the bench to no help, bought a new one today at our local small engine bandit for 15.53, no help. Armature air gap is set to .010. What don't seem right is the fact that from the secondary lead, the one that goes to the point box, to the ground wire off the coil I read a short, that don't make sence to me.

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HubbardRA

Marty, the points turn off and on the ground for the coil. The magneto provides the voltage to the positive side of the coil, or the battery does that on an external battery ignition. Both types run the voltage through an ignition switch. On a magneto system the positive wire from the magneto is grounded to shut off the engine. On a battery type ignition the positive wire is opened by the ignition switch to shut off the engine. Hope that is understandable.

Basically you will need a coil with an internal ballast, or you can use one without a ballast, then use a ballast resistor from a 60s Dodge or Plymouth in series with the coil. It will run without a ballast resistor, but will burn the points much quicker than with a ballast resistor to lower the voltage. A coil from a K-series Kohler engine is the best one to use. They are already set up for use on this type of ignition.

If you have more questions, send me a PM or email.

Rod

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GLPointon

Your key switch is what grounds the points to kill the ignition system. Thats why a chaffed wire will ground it out too like Ray was saying. I've had key switches that were grounding out the ignition even in the Run position. Can check it with an ohm meter. Unplug the harness then the key switch should show "grounded" only with the key in off position(on the terminal to the ignition/points)

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GrincheyOne

Check the terminal strip on the points (top), if this has rotated, it is possible that the points are behaving as constantly closed. With a coil, the

ground has to break in order for the DC current in the coil to fluctuate and

generate high voltage to the plug. to check this slip a piece of index card between the points, then check to see if the point wire is showing as gounded. There is no easy repair for this terminal, except replacing the points.

Wayneid="Book Antiqua">id="size4">

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Ronald Hribar

I think if you check between wires you will find continuity

I was told the only way to test coil is some fancy machine

Or replacing coil with a known good one

I thought my coil was bad because it had continuity to ground

After many $$$$ later found out original coil was good

Can use any car coil to test with

But have to have certain one to run permanently

I am sure you have a used coil from Dodge truck

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perry

sorry to hear you had to pull the engine back out. on these old cast iron briggs i have never had a flywhel key go bad and have never had to repolorize one. yes it does happen but 99% of the time its dirty or bad points or bad coil or wire.

I have a kohler 12V tester coil setup with aligator clips . on the FDT's i run hot wire from battery to a toggle switch, then hot wire from switch to the + side of the coil. then run a wire from the negative side of coil down to points. the toggle switch just turns power off/on to coil. The old gilsons are known for bad wire harness.

I would bypass ignition , harness and everything else and just hook up the coil direct and see how it runs. just treat it like your running it on the bench. or if you have another oil pan do all this while its sitting on the bench.

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dentwizz

Before converting to magnetron, I had a couple cases where it was the same as the listed symptoms just from dirty points. At the time the plunger hole was allowing a little too much oil out and it was fouling in the points contacts. The points have to be pretty much perfect to work reliably, any non-perpendicular faces or arced edges can impair the operation.

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