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Wisconsin THD timing

Dwride

Registered
I'm trying to get info on setting the timing. I don't see any markings on the gear to match up with the mark on the magneto. Any help? Thanks.
 

TWest

Registered
The timing marks are located on the the flywheel shourd (remove screen), flywheel, and on a specially marked tooth on the magneto gear.

Remove the flywheel screen and look on the shoud, there should be 3 ticks imprinted on it one at 12 o'clock and two others around 2 and 10 o'clock. There should also be an x-marked vane on the flywheel. To time the engine you must make sure that piston 1 (closest to shroud) is at T.D.C of the compresson stroke, simply remove a sparkplug to determine this. To be more accurate the x-vane on the flywheel should line up with the 12 o'clock mark on the shroud. Once you have done this there is a pluck on the gear case, where the magneto mounts that needs to be removed. The last step is to find the x-marked tooth of the magneto and mount it so that the x is visible through the bottom half of the plug hole.
 

jamest

Registered
If you are trying to install the magneto there should be a plug on the gear cover. when the engine is at TDC you should be able to see a mark on the magneto gear through this hole.
 

jimybud

Registered
Is there any additional fine tuning available? I had the flywheel at tdc and the marked tooth of the mag was visible from the plug hole.

I still could not get it to run. It appeared as if it was firing a bit ahead. It also back fired at times.

Additionally, I set the marked tooth one before and one after the plug hole assuming that maybe I was off a tooth. It behaved the same.

I also switched the plug wires and was able to get the engine to run on one cylinder.

Any feedback would be appreciated.
 

jimybud

Registered
Also, I printed the page within this thread and it was very helpful. I double checked that the plug wires were on correctly as specificed on the pdf file

Also both plugs were getting fire. And both cylinders appeared to have compression.
 

jimybud

Registered
I turned the engine by hand and noticed the mag triggers (or clicks) when the DC mark on the flywheel is at about one or two oclock. I assume that I need to adjust the mag so that the mag will click at TDC or a bit before.
 

jimybud

Registered
I figured it out. In addition to the mark on the face of a tooth, there is also a dot on the side of a tooth. These are separate teeth. I mistakenly assumed the tooth with the dot was the TDC setting when viewing from the plug. Once I realized their was also a mark on the end of a tooth I was able to get the timing fairly close.
 

Kris Golden

Registered
Gald you got it goin'! I wonder if you have a TJD instead of a THD Wisconsin. Swapping the plug wires on a THD makes no change. Mags on THD fire both cylinders at the same time - one spark is wasted in the exhaust stroke of the other cylinder. TJD alternates spark and has a different firing order. Swapping wires will change spark timing on TJD and you stated it allowed the engine to at least run that way.

Another point I would like to clarify is the impulse [clicking sound from mag - at cranking speed only] retards the timing and it should NOT fire at or before TDC - but well after. This will correct itself once the engine is running on its own and the clicking inside the mag stops. Again, glad you figured it out and best of luck! :wave:
 

John Newman Jr.

Subscriber
Age
64
Last Subscription Date
01/10/2019
The impulse mechanism holds back (retards) the mag to fire at TDC when cranking. It will advance the spark to 27° before TDC when running. You set the timing so the mag snaps when the flywheel is at the TDC mark (12 O'Clock) on the blower housing. There should be another mark on the blower housing at about 11 O'Clock. If you use a timing light while it is running, this is where the "X" marked vane on the flywheel should appear.
 

Attachments

lrose

Registered
Hi my name is lawrence I have a two cylinder Wisconsin I moved the timing marks where they belong to the x to the hole at top dead center it will not run if I moved the.on the magneto I marked the tooth with a dot is it will run that way, why what am I doing wrong help please thank you
 

homealone777

Registered
Forgive me please. I could read all day on the rules and still not understand. I'm a "Show me" person. Anyway, I have a problem (maybe), as I have taken the magneto apart to clean the brushes to get it to spark again. That worked, but this one is an AHH single and I don't wanna get my arm broke from kick back trying to start it! I know this is a bit off topic, but could someone please help me. I can do it the hard way by using another engine to get it started by using a belt from pulley to pulley, but I'd much rather know where the marks are and do it that way. Thanks, and May God Bless all of you!
 

John Newman Jr.

Subscriber
Age
64
Last Subscription Date
01/10/2019
Homealone 777,
All of the older Wisconsin engines time the same. Set your mag to trip the impulse exactly at TDC. The keyway on the crankshaft is one way to check TDC. Flywheel vane and blower housing should also have marks.
 

Zira

Subscriber
Last Subscription Date
03/24/2019
On the AHH with the lug drive, you will either be right or 90 degrees off. I usually set the engine at Top Dead Center (marked fin on flywheel at top, key way should also be up unless you have a clutch and/or gear reduction. Turn the magneto until it just snaps. Set it more or less in place and turn the engine clockwise slightly until the coupling lines up. Install the bolts holding the mag & there you go.
 
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