F-4 Mag timing.....

banjoman09

Well-known Member
One more question; (looks like the day for "mag timing" on here.) So, when I roll the flywheel to "D-C" , the points are already
open. (compression stroke) ; let me ask this - is the timing different for an F-4 than the Bosch mag that I took off? Is it
possible, like Moll said, the front flange bolts in a different set of holes for the F-4? or do I need to move that?I guess what
I am asking is this- "should the drive flange use the same set of holes for both mags?"...sorry guys but Im learning here- and
getting close! Thanks!
 
those holes with the 1/4 " bolts are for fine tuning the mag. u must remove and find the holes that make the mag snap at tdc.
that is the timing adjustment. mags like the h4 use a slot and just require to move mag once bolts are loosened. same deal with the distributer also.
 
2 different mags will use 2 different sets of holes the way it looks. If the points are open it is too far advanced. take the bolts out & turn the mag back so another set of holes line up. Keep doing it until it snaps at TDC.
 
You need to slow down, you ask as many question as the reporters on TV! it is not that hard.
A) TDC #1
B) Take the 1/4" bolts out of drive
C) Rotate mag back wards so rotor is point to #1 wire tower
D) Rebolt the mag drive.
This should get it started than you can fine turn after you see how it runs.
 
Let's see if I can answer your question. I'm only going to address the timing for an F-4. First, make sure you're on #1 TDC. Next rotate the mag shaft until the pointer on the distributor plate is pointing to the #1 plug (should be about 1:00 o'clock). This can be done by laying the mag on its side and rotating the shaft. That way the impulse is taken out of play. The breaker points should be just about to open, in other words, they should be right at the high point of the cam. Without disturbing this setting, set the mag on its bracket close to the mag drive. The fingers on the drive should line up with the slots on the mag. If they don't, remove the 1/4" bolts, rotate the drive plate to match up with the mag and reinsert the bolts. Slide the mag into place, install at least two mounting bolts and rotate the engine over. The pointer should land back in the same place as before. After putting the cap back on, start her up.
 
i addressed your problem perfectly! of course not both mags will not use the same holes! should experiment with it and you will get the answer.
 
yes- making more sense to me...I dont find the lever to pull up to disengage the mag on this one...and I was trying to rotate the mag to no 1. and keeps stopping before it gets there....against the spring-load...so I will do back out(I have it off) and lay it on its side.(didnt know that!) and try it again. Thanks!
 
Got it! Im just trying to explain everything thats going on! Mr Moll....please contact me on the pulley! Thanks!
 
The most important determining factor of static timing is WHERE DOES THE IMPULSE TRIP. That is what determines when the plug fires at cranking speed. Before you do anything, observe where the TDC timing mark is when the impulse trips when you slowly crank the engine. Adjust your coupling position so the impulse trips at TDC or slightly after, NEVER before.
 
I thought the plug fires when the points open! Hopefully, the impulse has sprung generate a higher voltage.
 
that is correct , the plug fires when the points open,... and once the impulse trips thats what opens the points. that is the purpose of the impulse , to produce a good hot spark at slow cranking speed.
 
All F4 and E4A mags are timed with the impulse disengaged. The older F4 mags will have a small, square tab at the top right of the impulse housing when looking at it from the drive end. Pull the tab up, and that disengages the pawl on the impulse.

If you have a later F4 mag, the impulse disengagement tab was eliminated. As per the IHC manual, use a 10D finish nail inserted into the Gits oiler cup on the face of the impulse housing to lift and disengage the impulse pawl. Leave the nail in place until you are done timing the mag. Others have provided proper procedure to do that.

your initial timing is done without the impulse engaged. period. This can all be done with the mag installed on the tractor, and actually should be.
 
Yes.....mine must be a later version. Im learning from all of you- I should be able to get this now....thanks for the help!
 
Do you have a pulley for your W-30? If not, get one and a flat belt. Then you can use another tractor to turn the engine of your W-30 and avoid cranking. You will also avoid the issue of the impulse.

After you get the pulley, here is how to easily start your W-30:
Remove the spark plugs.
Remove the valve cover.
Remove the front observation cover on the left side of the engine.
Hand crank the engine until both valves are closed for cylinder #1.
Look/feel in side observation cover to make sure that cylinder is at Top-Dead-Center (TDC). No worrying if you have the timing mark right-with both valves closed and the crank straight up, you are at TDC.
Remove the distributor cover on the mag. If it is at 11 o'clock, you are close to the correct timing. If not, disconnect the mag and rotate it until the distributor is at 11 o'clock and reconnect the mag.
Put the distributor cover back on.
Put the valve cover back on
Put the front observation cover back on.
Put the spark plugs back in.
Put the belt pulley on.
Put the flat belt on the pulley and the other tractor (yours or a borrowed one) with a twist. This will make sure you are turning the W-30 engine in the correct direction -- The top of the W-30 pulley should move forward (Clockwise as viewed from the left side of the engine.)
Put the W-30 pulley "In gear"-make sure W-30 itself is "Out of gear."
Tighten the flat belt between your W-30 and the other tractor.
Put the belt pulley on your other tractor in gear and let out the clutch. This should begin your W-30 engine to turn over at a slow to moderate speed.
Adjust the mag, adjust the carb, adjust the throttle until your W-30 begins to run by itself.
Put the W-30 pulley "Out of Gear." The W-30 should continue running. If it doesn't, try starting it again using this "Twisted Belt Method."
Good Luck and enjoy your W-30! They are a great tractor!
 
Thank you F-Dean....... my tractor is "in time" TDC is on mark; I dont have a pulley until MOLL gets ahold of me so I can go get it. Hopefully soon!
 
lol....no! Too dang cold this way right now...no heat in shed....thanks for asking! I hope to try again this week.
 

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