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roma3112

TO REPOLORIZE OR NOT

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roma3112
HERE IS A QUESTION FRO SOME BRIGGS GUYS. I REPLACED THE POINTS ON MY 3112H WITH A BRIGGS MAGNETRON MAGNETO SETUP. i HAVE BEEN TOLD THAT ON THESE OLD ENGINES THE FLYWHEELS MUST BE REPOLORIZED TO WORK. AT THE TIME I DID NOT KNOW THIS AND PUT THE UNIT BACK TOGETHER AND IT RAN OK. AT TIMES HOWEVER I GET A BACKFIRE AND TO ME IT JUST DOES NOT SEEM TO START AS QUICKLY AS IT DID BEFORE. TO GET HER GOING I NEED TO PUSH THE BUTTERFLY ON THE CARB SHUT AND "PLAY WITH IT" TO START IT UP. i GUESS THIS IS A LONG-WINDED WAY TO ASK THAT IF YOU REPLACE THE OLD COIL WITH A MAGNETRON UNIT MUST THE FLYWHEEL BE REPOLORIZED, (MINE RUNS AS IS) AND ALSO COULD I BE DOING ANY HARM USING IT AS I AM . THANKS JOHN

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Dutch
The flywheel only has to be repolarized if it doesn't trigger the Magnetron. Obviously the polarity of your flywheel is okay. Don't worry about it. Is the gap between the Magnetron and flywheel set properly? Are the spark plugs new? Sounds more like you have a fuel (carb) problem. Maybe even a flywheel key problem.

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roma3112
thanks dutch yeah i was leaning towards fuel myself, the reason for the post was that we had a factory briggs guy at work yesterday and he said "YA GOT TO DO IT" If it aint broke dont fix it is my opinion, but i just wanted a second opinion. thanks john

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PatRarick
With Magnetron, the engine has to turn faster to generate spark, than with the breaker points. I believe the minimum to generate spark with Magnetron, is 350 RPM's. A weak starter/generator, slipping starter/generator belt, or a weak battery, can cause the engine to spin slower, making for weak or insufficient spark to easily start the engine. Other causes could be incorrect air gap between the ignition armature and flywheel, too little valve clearance, or leaking valves. Pat

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roma3112
hmmmmm I think you may have hit on somthing! I have noticed that when my uncle had the machine >> turn the key poof there she went Post upgrade she spins and spins and finally poof in a defiant sputter she comes to life. If i am not mistaken when i rebuilt the motor the air gap was set to specs (about 10 thou) Compression is strong at 120psi or over and the carb is brandie new at $140 Thanks for the extra info, i am debating on if i should put it back to the way it was, i am leaning towards dealing with the problem because on that 3112h r&r of the engine is a good day long project. thanks john

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dirtsaver
Morning John! Your post may be just in time to save me some trouble. I am bringing a 3012 back from the dead and everybody tells me to upgrade to the Magnetron system, but after this I think I may stay with points unless I hear a real good reason to switch. I like the idea of the "slow roll" start instead of the higher rpm. Good luck with whichever you pick! Larry

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powerking_one
John, I am putting a Magnetron kit on my landlord 2110 also. I removed the points plunger bushing/push rod assy from the block and installed a 3/8" welch plug. You have to put the 10-24 mounting screws and a 8-32 screw in place of the points adjuster since the holes go clear through the block. Larry, the points and condenser are in excess of $25.00 now. The Mag Kit was $10.50. The motor was coming out of the frame anyway, so...... why not factory upgrade the ignition to late 20th/early 21st century specs? I've never heard of a magnetron failing. My 2cents worth, Tom(PK)

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roma3112
hi all dirtsaver i would probably lean towards keeping it stock, in my case i had a bad coil so the upgrade was about 50bucks. i AM NOT impressed with the proformance of the magnetron, while it has its benefits for sure i think the origional ignition (especially finding about the higher rpm's needed for magnetron) is the way to go. Ehh so what if the points are $25 or so extrapolate that over their total service life and it figures out to be cheap. I think many of my little glitches all stem back towards the ignition upgrade, 1) i have a new battery now new starter belt and luckily a v strong starter/gen, for sombody lacking in any or all of these areas i think points may be a better alternative. ps good luck with your project r&r of the 3112 engine is not a fun project just take your time, also for my 3112 engine service i bought an antique engine service manual right from my briggs dealer it has the 300421 cast iron engines in there, it is a real help especially if u need to tear the engine down.

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simtrac
Hi Guys,in reply to your ignition upgrade to magnetron, my 3410h has a worn points plunger,lucky me, on e-bay ,I came across these electronic modules some guy had,bought them, took 2 minutes to take points wire off,install on module,mount module to points cover,and presto! the ole' briggs fires wayyyyyyy easier and seems to have twice the power. part was made in australia, will have to look if I still have box it came in. Dunno--- maybe 'nuther option simtrac

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G.Kiebler
Sure hope the battery does not go dead and you have to pull start those magna trons, you might have your hands full( trying to spin the engine 350rpm) ,my pull rope and points has saved me some walking.

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Rebldr55
John, I also had to decide to upgrade, or stay stock on my B-10 ign. but after I was told, that it could be up to 2 months during the summer months to get my flywheel back from brigs, I stayed stock, personally im glad I did, a couple of spins and she fires right up. Just my opinion. Rebldr55

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