Mega Fire Ignition Module on my 16 hp Briggs

[DanD]

The 326431 engine in my 7016 needed a new set of points (I think they go bad because of the tiny amount of oil that leaks around the plunger even though the seal and plunger were both new when I overhauled the engine a few years back). So, I decided to try a Mega Fire module which I received and installed yesterday. The engine seems to run perfectly, at least for the 10 minutes that I ran it so far. However, I have a few questions and would like your comments. 1. The instructions say to mount the module where there's air flow, I assume for cooling. However, I would really like to mount it under the old points cover just for good looks and because the wires reach there and there are mounting holes with good grounding for the module. Is it ok to mount it there or would I be asking for a cooked module some hot day next summer when I'm half done with mowing? I also use this tractor for snow blowing and thought being under the cover would protect the module from melting snow, or isn't moisture a big concern? 2. I overhauled this engine myself a few years back, but can't remember, will the point plunger pull out of the engine if I take the points off? Briggs has a plug for the hole, part # 231143 for $2 and some cents. Anyone seen these? Could this plug be removed and the plunger and point be reinstalled? I ask this in case the module doesn't work well in the long run and also because this tractor still belongs to my father and I told him I wouldn't make any changes that couldn't be undone!!! 3. I remember when I reassembled the engine after the overhaul that the coil has slotted holes for the bolts that attach it to the block. If I rememebr correctly, it was supposed to be slid all the way in one direction if the engine was being operated on kerosene (anyone ever seen this?!) and about in the middle for gasoline. Since this is really the only control for timing with the module, I was just wondering if it needed to be or should be adjusted at all. Is there a way to test for proper ignition timing with this setup or is it simply if it seems ok, then it's ok? Thank-you for reading my long winded questions!

[B-16_IC]

The coil has the slots for setting what Briggs calls air gap between the coil and the flywheel. I have never heard of changing it for different fuels, but then I am far from knowing everything. The gap setting is in the manuals. The only way to change timing is at the flywheel key, so don't worry about that.

[Paul_B]

I mounted my megafire module on the inside of a frame rail. This location will be cooler and should have fewer vibrations: both can shorten the life of electronic devices. I also didn't mount it under the cover so I could basically leave the points in place should I have to revert back to them.

[RayS]

The air gap that the coil is suppose to be set at is .010 .

[powerking_one]

Dan, I would not think it'd be a problem mounting the Mega-Fire module under the points cover. Modern silicon semiconductor devices can easily handle +85 degrees Centigrade. After all, condensers/capacitors are stressed a lot more at this temperature (also under the points cover). Assuming the cooling system/fins are kept clean I'd think the engine block temp's under the cover would be in the acceptable range. If the module does need "air flow" cooling, you could mount it flush to the block with a high quality heat sink compound (like Arctic Silver; http://www.arcticsilver.com/as5.htm). You could aim a now cheap infrared pyrometer (like from Harbor Freight Tools) at the points cover to really see the temp before proceeding. Tom(PK)

[DanD]

Thank you for all who replied to my post. I just got back home from helping my father pick corn and while there, I decided that I would probably do what Paul described. Basically leave the points in place and mount the module elsewhere out of view. I also got out my dad's Briggs service manual to jog my memory from 5 years ago. The change in timing when changing from gasoline to kerosene fuel is for engines already equipped with the Magnetron ignition. The first picture shows that process. The second two pictures show the procedure for timing the armature when using breaker points. In a nutshell, you begin by having the flywheel sitting loose on the crankshaft, just held in time by the key. Then you set the point gap at .020. Next, using a light or ohmmeter, you turn the crankshaft until the instant where the point just begin to open. Then you see if the arrow on the flywheel is in line with the arrow on the armature bracket. If not, you slide the bracket on its slotted holes until it's in line. Then, slip off the flywheel, tighten the screws, install and tighten the flywheel, then install the armature and set the air gap. I guess I can assume that if everything was correct and timed properly with the points, then everything should be just fine when installing the module. Is that correct? Here are the pics from the service manual if anyone is interested.