f-12 timming

farmerjim72 · May 24, 2016

I am having a problem getting the final timming on the f-12. it runs but not very well had to put a motor in it due to a cracked block and it has good compression. and found a good mag that has spark, better then the old one. it sounds like the timming is retarted even if you set it to fire after or before top dead center. tried to use the pin lock on it but feels like theres nothing in the mag to lock it to. got it right now that it impuse kicks in right before tdc and I have tried it after. just seeing if any one has a idea what im talking about and doing wrong. im just trying to get grampas first tractor to red power this year.

Tom Fleming · May 25, 2016

first off, welcome to the forum. A couple of questions. What plugs are you using and are the plug wires copper core? Graphite or composite core wires are NO good for a mag system. Also, the mag mounting plate needs to be clean and free of paint so the mag has a good ground.

Let's start with those questions, then we can move closer to a diagnosis.

Dave Allgire · May 25, 2016

I'm assuming your retard lever is in the full non-retard position after you've cranked it and it is running. Technically your mag should be timed for firing on TDC. The next thing I would do is check if you are running too lean or too rich on the fuel adjustment of the carb. While it's running you can turn the mixture screw in or out sloooooowly and listen to the sound of the engine. And I agree with Tom, plug wires have to be copper core and a clean base.

DGinVT · May 25, 2016

Make sure inside the mag, if it is adjustable, that the "lag angle" is properly set to the right number of degrees as called for. I had to slightly adjust mine in a WICO X after many years of use.

36F30 · May 25, 2016

First you really need to get a mag rebuilt, solves lots of issues, Nebraska Kirk on here does excellent work. Pull plug wires, rotate #to top dead center and slowly keep going until the mag trips, now turn the motor Backwards until the engine is at TDC again. Now look where the rotor is, If its not exactly centered on # 1 then remove the bolts in the coupler and set it so it is. Mag timed.

Dave Allgire · May 25, 2016

I reread your question(s). What are you calling the mag lock pin? If you are referring to the eye pin that has a square cover on it at the front of the mag, that is used to release the impulse coupling when you are turning the engine over say, to check the timing. If you pull up on it, it releases the impulse coupling. Down is its normal position. The other style is an oiler type cover that you would use a #8 or #10 finish or #6 nail to insert to raise the impulse to do the same thing. Hope this helps.

farmerjim72 · May 25, 2016

champion w-14 copper core wires and mag plate is clean

farmerjim72 · May 25, 2016

hi dave has the oil type cover just haven't felt anything to lock the impulse.

farmerjim72 · May 25, 2016

thank you dg I will look at the lag angle

farmerjim72 · May 25, 2016

thank you f30 I got a mag rebuilder now and the timming idea sounds like it could work.

Tom Fleming · May 26, 2016

There is no lag angle adjustment on an IHC F4 magneto. If the mag is hot, and the wires and plugs are good.......you have a carb issue or a leaky intake manifold...............or leaky valves. Take 1 step at a time.

If you need help timing it correctly, you can give me a call, I'll be happy to assist. eight one four dash four three nine - 1452

farmerjim72 · May 30, 2016

i got it sunday running good thank you

f-12 timming

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