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steve(ill) 
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Location: illinois
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 Topic: ODD Mag operation
Posted: 18 Apr 2022 at 12:00pm |
Went up and connected the plow on the "B" and brought to shop to adjust. Made adjustment and went to start tractor. Normally starts in 1 revolution of the engine.. Cranked for 10 seconds and would not start. Plenty of gas. Pulled a plug and checked spark. Was a little weak ( maybe?)... Mag has been on for 15 years so i pulled it off and took to shop. Cleaned the point face, installed a new plastic rotor end ( old one had burnt edge) , cleaned up the cap, installed a new condenser, coil was new 15 years ago... Checked on bench and HOT SPARK and impulse winds up and FIRES... GREAT... Put back on tractor and NO START .. ???? Pulled plug and check spark ... rechecked timing.. impluse fires at TDC...... NO START ??? ...............Took mag off spare tractor, cleaned and tested spark.. put on the "non runner" .... fired up in 1 revolution of the motor !!!
Appears to be something with the MAGNITO, but impulse works, good spark, that should verify coil and condenser ??? Thinking about pulling the impulse apart and checking inside.. Fires fine on the bench, but dont know what is happening at cranking speed. ( has a 12 volt battery on 6 volt starter)....... This tractor has been GREAT for 15 years..
Anyone seen a MAG that impulse winds up and FIRES on the bench, but has a problem inside ? Hard to believe it is the coil or condenser !
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Like them all, but love the "B"s.
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TramwayGuy
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Posted: 18 Apr 2022 at 12:49pm |
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a). Maybe the 12v battery spins it fast enough to override the impulse?
b). Might be firing on TDC mark; but on #4 instead of #1?
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steve(ill)
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Location: illinois
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Posted: 18 Apr 2022 at 1:10pm |
i have had the 12v battery and this mag for 15 years. Always starts on the first revolution... Timing set on #1 compression.. checked several times...And the problems STARTED out of the blue.. prior to doing any changes......... new mag... no problems..
Its the MAG, i just dont know exactly what... I dont know if its possible for he mag to increase to 30 degrees during the first revolution .. BEFORE it fires and starts ? ... was OK for 15 years.
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Like them all, but love the "B"s.
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steve(ill)
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Location: illinois
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Posted: 18 Apr 2022 at 2:40pm |
have not disassemble the OLD MAG.. but found this........but...my impulse seems to work when rotated on the bench ??
Edited by steve(ill) - 18 Apr 2022 at 2:42pm
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Like them all, but love the "B"s.
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JC-WI
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Posted: 18 Apr 2022 at 2:58pm |
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Could it be your switch/wire grounding it out to the point the mag can't fire?
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He who says there is no evil has already deceived himself
The truth is the truth, sugar coated or not. Trawler II says, "Remember that."
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steve(ill)
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Posted: 18 Apr 2022 at 5:26pm |
I give up......... i took the ORIGINAL mag impulse apart.. OF course the WIND UP spring was OK as that was working on the bench.. There is a small spring on each weight that holds the weight in place when you crank, then the weights FLY OUT and advance the spark when running.. That looked OK, but i cleaned / lubed, checked and seems OK.. Reassembled and put on tractor.. NO START ........ put my SPARE on and starts in 1 revolution of the motor... ready to STOP right now and MORE THINKING prior to more testing !!
Not a CLUE right now.. Wonder if condenser / coil can fire when turning by hand, but can not keep up when spinning 100 RPM ?? I did change the condenser yesterday and did not help..... kill wire disconnected all day long during testing.
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Like them all, but love the "B"s.
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steve(ill)
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Posted: 18 Apr 2022 at 5:29pm |
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I guess i could install the OLD mag... clamp a bar to the motor and clamp all 4 spark plugs to the bar to ground.. connect the plug wires and CRANK while watching the plugs to see if they can all spark at 100 RPM ??
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Like them all, but love the "B"s.
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juniorp53
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Posted: 18 Apr 2022 at 7:58pm |
just dealt with similar issues... snap mag by hand and get a spark ...on tractor nothing seems these new condensers more are bad then good
it was a new out of the box eciplins that i wrongly assumed it was good
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steve(ill)
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Posted: 18 Apr 2022 at 9:10pm |
Well, i had the original condenser, then put a NEW one in... no start on either...... I guess thats my next test to change the condenser -- then coil -- i have "spare" parts for test.
I though condensers were GOOD or BAD... didnt know they could fire "sometimes" ??
That worked for you ?
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Like them all, but love the "B"s.
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juniorp53
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Posted: 19 Apr 2022 at 9:29am |
i was under the same impression good or bad with nothing in between. i had just installed my coil its brand new and ohms out good. put new condenser in at same time few pops and some sputtering all i could get out of it . gave up too cold to work on and too expensive to heat garage
this spring i reinstalled battery ... could get a pop and that was it
took mag off turn by hand spark.. back on tractor one pop then nothing
put extra extra spare condenser on ..now starts in half a spin or so
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steve(ill)
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Posted: 19 Apr 2022 at 9:53am |
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Im done pulling the mag on and off the tractor right now......... thinking i can remove the IMPULSE and then spin the mag with an electric drill on the work bench and look for "FIRE" at the plugs... then change the condenser / etc and retest till i find problem. Only have one more NIS condenser in stock... Might be time to REINVEST !!
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Like them all, but love the "B"s.
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Eric B
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Posted: 19 Apr 2022 at 1:03pm |
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Yep... I had the same challenge. I hooked up all four plugs (taken out and grounded) with mag still on the tractor. All gave sparks but weaker, would not start. In a man's mind you don't want to cave to a problem but I put my pride down my pocket, turned it into a distributor with the external coil and voila... instant start, same condenser too. Had the same thing with one more, I stuck the impulse coupling end into ATF (about 1.25" deep) for a day or so, it was fixed after that.
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Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!
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Steve in NJ
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Posted: 19 Apr 2022 at 1:05pm |
Over the years, I've had some goofy stuff happen on the test bench with these Magneto's. They do keep you on your toes. Could be a bad set of points. Mag works great on the test bench firing all plugs. Install it on the Tractor and nothin'. WTH? Take it off, do the condenser gig, back on the tester, looks good again. Install it on the Tractor...nothin'. WTH? And this is with a fully charged magnetic rotor to! Put in another set of points I use for testing. Bench tests good. Put it in the Tractor and fires up like never had a problem.... Had that with a few customer Mags also. Sometimes ya just can't esplain it!  Steve@B&B
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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
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bluewavecaptain
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Posted: 20 Apr 2022 at 5:36pm |
Just because you're getting spark, doesn't mean you're getting strong spark. Our RC had a similar problem. If you shut the tractor off when warm, would not start. Let it cool down, would fire right up. Tried everything. AND the mag was rebuilt from a reputable shop. Had spark, fuel, etc. Turns out it was a defective coil. Wasn't pumping out enough spark when it warmed up. We found out when I swapped the mag with another one. Never had an issue. Shop put in a new coil under warranty.
Charles
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Charles(Two Rivers,WI)
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DaveKamp
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Posted: 20 Apr 2022 at 11:22pm |
Start off by remembering that it is a machine, not a supernatural force dominating you gleefully.
Next, look close, and ask yourself what is 'different'.
It is most often, that a magneto test stand will NOT support the magneto in same way that being bolted to the engine's auxiliary will. The drive coupling on test stand is frequently not same as that which is on the engine.
One possibility, is that the act of mounting it on the engine, changes how that coupling fitment works out....
perhaps the coupling is slightly thicker, and the mag base gasket is missing, so when installed, the coupling is pushing hard against the mag shaft, which is causing the point cam to not actuate properly...
Or the base gasket is a bit 'too good' at isolating the mag from the block, so it's not getting a good ground? Connect a test lead from the mag case to the block, and see what happens.
Perhaps clamping force on the mag case 'ears' is deflecting the case in some unseen spot, resulting in the mag's windings shorting out?
There is a reason, it is not magic.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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steve(ill)
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Posted: 21 Apr 2022 at 9:02am |
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The mag WORKED for 15 years every day... Then DIED one day.... Its INSIDE the mag.
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Like them all, but love the "B"s.
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steve(ill)
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Posted: 22 Apr 2022 at 12:30pm |
Well, it rained all morning so i thought i would stay in the shop and look at the magnito. I took a steel strap and drilled 4 holes and taped them to hold 4 spark plugs. I took the impulse off the mag and just put a 3/8 nut on the shaft so i could spin the mag without the low speed SNAP ( impulse).
The plugs and wires are "OLD" parts previously removed and replaced on tractors.. Spun the mag over with a 20 v drill at about 2-300 RPM. Very small orange spark on each plug.
2. Replace the condenser for a second time.... sill small orange spark at all plugs 3. Decided to take the coil off and install a NEW one and test... this is where it gets interesting.. There are two setscrews in the aluminum case the HOLD DOWN the coil. See the two white circles above. 4. One of the screw head is damaged and will not come out. Took the other screw out and it was barely snug. After removal i see "white powder" ( aluminum corrosion) on the screw threads. I could wiggle the coil so the "STUCK" screw was barely touching the coil. Pried the coil out and removed. 5. Got the NEW coil out of the box ( about 15 years old) , and it has no "brass ear" installed !! ....... so i go to take the brass ear off the REMOVED coil..... the screw is steel, not brass... and it has some CORROSION on it also. 6. Cleaned the coil screw and coil set screws and aluminum case thread hole and installed the NEW COIL. 7. BIGHT BLUE/WHITE spark at all 4 plugs.. Probably 3-4 times as big of spark as i had an hour ago.. 8. Removed the NEW coil and installed the ORIGINAL coil, with the CLEAN BOLTS and MOUNT THREAD HOLE... Locked down the ONE set screw ( other is still "STUCK").. 9. Bight BLUE/WHITE spark at all 4 plugs !
Have not tested on the tractor yet, but looks 100% better on the bench... Moral to the story is corrosion on ANY contacts or grounds can be a problem..
And when i went to put the NEW coil back in the box, i FOUND the brass ear and new screw in a bag at the bottom ! ........ Good thing it was not installed.. that forced me to check the contact on the OLD COIL (new 20 years ago) and find some corrosion..
Edited by steve(ill) - 22 Apr 2022 at 12:41pm
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Like them all, but love the "B"s.
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Eric B
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Posted: 22 Apr 2022 at 12:37pm |
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Thanks for sharing, this is very important information, enlightening to all of us tinkering with mags!
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Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!
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WF owner
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Posted: 22 Apr 2022 at 2:20pm |
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It's not at all uncommon for those bolts that hold the coil to be set or damaged.
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