Briggs Magnetron Coil upgrade?

[rjgoth]

I am thinking about getting rid of the points and condenser system and going with the Magnetron Coil, and having the flywheel re-polarized. I am a bit reserved in doing this and I was hoping that some of the members may have some helpful advise on doing this. Has anyone had any luck with a conversion like this? Has anyone had any bad luck? Where can I get a coil for a 300000 12 HP briggs engine from 1971? Part number? What is the difference between re-magnetize and re-polarize? Thank you for your input. Ryan

[stumpy]

I've done one for a friend...worked pretty good, and simple enough. Personally speaking, I kinda like points...it's something I can see and understand :). Buuuuuttt...I have gotten into the habit of replacing the mag system with an automotive coil type system. It's cheap, easy as pie, and the spark is a whole lot hotter and immediate. That can be a real plus in cold country, and I've found it works great. Plus, it reduces the number of potential times the ol' flywheel has to come off. On the down side (and, in my mind the only possible disadvantage), you have to have a good battery and charging system.

[roma3112]

ryan if you do search of the past posts there are many instances where members have discussed this issue. I myself tryied it on my 3112h with a 300421 CAST IRON BRIGGS, i WAS NOT HAPPY WITH THE RESULTS AND SWITCHED BACK.. I found the points allowed the engine to fire at a much lower rpm and in my case it ran smoother. Yes points for these engines can approach 30$ or so but my origional set lasted 30+ years so i dont think cost is an issue. there are other less invasive kits that members have had good results with. basically they use the existing coil and connect where the points would be. I think it is basically some sort of electronic trigger. I am sure sombody can post with the name of the product. I for one would stick to the points especially if your engine may not be in the greatest of shape, either starting system wise or compression wise. The magnetron will require the engine to spin considerably faster to get going and you may have a problem if the engine is "tired" good luck john

[ambler]

I talked to a Briggs engineer on their hot line. Re polariztion is restoring the polarization of your flywheel magnet. If it passes the screwdriver test it will be fine. UCD located the trigger under the points cover. Module is about $16 from Briggs. New Coil with integral solid state is about $40. The two briggs that I am rebuilding will have magnetron when I am done. Starter generators were just renewed.

[fuzy]

To switch to magnetron you need to have the flywheels repolarized. We have done it many times for our customers. We were told directly from briggs that you need the flywheels redone. I think briggs will do it for a small fee. If I am not mistaken the coils are typically mounted backwards in point ignition on some of the old cast irons. However the magnetron must be installed the correct way and the magnets are now backwards. You should only need about 500 rpm's to get a magnetron to fire. And it should run just as smooth as point ign at low r's because you typically wouldn't set your r's much lower than 1200-1500 anyway. I can ship you a coil just drop me a line. I have them instock and they run about $40. John

[MPH]

John, why would you want your idle set at 1200-1500rpm. When the plugs clean, my B-112 putts along at about 450..MPH

[roma3112]

ryan Briggs will re-polorize it for free but you have to pay the shipping, on somthing as heavy as one of thoise flywheels it may be 20-30 bucks. Another thing you want to consoder is to change the complete coil the engine will have to be removed (as i did on my 3112h) not a great way to spend the weekend. If you really want to get reid of the points try one of the trigger modules it is soo much easier to install. If you do decide to go the whole route and change the whole coil MAKE SURE the flywheel nut is tightend to spec it is really tight, on my 3112h i want to say it was 100/ftlbs ?? I cant tell you how many keys i sheared when i tryied the magnetron conversion. I was so used to dealing with 3 -5 hp mower engies that i did the old "hand tight and 1/2 turn thing. i must have taken the engine off 3 times before i caught my mistake. good luck john b

[fuzy]

Roma is correct to make sure you torque it but the torque value is actually 145 ftlbs. The recommended idle rpm is in the 1500 rpm range but I do know many guys that love to lower the r's on old casts way down low. Sounds tuff when they sit and give the pop pop of barely spinning fast enough. John

[HubbardRA]

Idle speed has a great effect on cooling. 500 RPM does not move enough air to adequately cool the engine. 1500 RPM does.

[patrician12]

Stens sells a module that takes the place of points w/o repolarizing the flywheel and it is only about $15.00.

[thedaddycat]

Marty, I'm still chuckling...... I just was skimming the replies and went through yours so quick that I thought it was trying to say that you idled along at 450 miles per hour...... I've had folks over and started the Putt Putt up and I bet it doesn't even make 500 RPM when she first starts. You can almost count the shaft turns while you watch..... That's how she got her name!!! BTW, once she warms up I bump up the throttle to about 2/3 (where the little arrow that points left is on the throttle control) and that's the only speed I ever run her at. I don't want to max out a 40+ year old Model 19 and even at that setting she has enough power to do anything I wnat with her including tilling or earth plowing with the moldboard plow.... I was out today and decided to see if I really could count the RPM of the Putt Putt at idle. I started her up and sat there actually counting the "putts" for a full minute....... She idles at 297 RPM(cold)!!!

[Dutch]

Ryan, The most important thing is to get spark to the spark plug and get the engine running. There are several ways to achieve that on a Briggs. Everyone has their own preference. Here are your options: 1) OEM points and condenser ($20-$25) utilizing the OEM armature ($25-$40). Must have good camshaft, points plunger, and plunger seal. 2) Eliminate points and condenser by installing a Briggs magnetron armature ($25-$50). May have to have your flywheel repolarized (free but shipping cost) depending on your particular engine. I have installed magnetron armatures on engines that "should" have required flywheel repolarization but didn't. 3) Retain OEM points and condenser but convert to battery ignition ($ depends on whether you need to replace OEM points and cost of battery type coil). 4) Eliminate points and condenser but retain OEM armature by installing an electronic trigger ($10-$20). Does not require engine removal, BUT will work ONLY if your OEM armature is good. Once again, everyone seems to have their own favorite method, approach, reasons, and valid opinions.

[Ronald Hribar]

I think I understand on how to convert to coil ignition. You use your battery as the electrical source and hook it up to the points,the points then feed the coil and ultimately the sparkplug. Now instead of grounding out ignition you shut power off to points. If that is all correct I have several questions. 1.do you start and run with 12volt or do you use a resistor for run mode? 2 Do you need different type of ignition switch? 3 Can you utilize what used to be ignition source for charging? with either the S/G or gear setup?

[thedaddycat]

The coil set ups that I have run the hot wire to the coil and the coil ground to the points. The points act to switch the ground on and off, but it works fine.....

[roma3112]

kirk With the self-made automotive style ignition system, is there any concern about a condition in wich the flywheel key sheers and the ignition still sparks possibly causing damage. I was running the schematic through my head and poof this question comes to mind. I assume to convert you forgoe this protection and just hope nothing happens? john