re-timing magneto
10-19-2004 | 07:13 AM
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From: cape coral,
FL
re-timing magneto
What prcedure do you use to re-time a magneto engine. I am interested in advancing the timing on a 45cc homey to 28-30 deg BTDC.
Any help appreciated. red
Any help appreciated. red
10-19-2004 | 10:29 AM
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RE: re-timing magneto
The key is only there to tell the assembler where to put the flywheel...You can leave the key out and put the flywheel on wherever you want it...I haven't used a key on my conversions for 15 or 16 years..The flywheel tightened on the taper will never slip if kept tight....[8D]
10-19-2004 | 01:45 PM
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RE: re-timing magneto
Ron...Nope..When a flywheel is a good fit on a taper it takes a puller to get it off...Our 289cc 30+ hp racing engines have no key on the prop hub, just a long perfect taper, about 2 degrees..No Loctite, never slip....Only engines with a straight shaft need a key...The usual key is so soft it shears when the hub gets loose..
3W engines use some kind of Loctite on the tapers, along with a key..Takes a good bit of heat and a puller to get the hub off the crank...But they fit the bearings loose enough in the cases to use Loctite on the bearings ..Must be for easier assembly...
3W engines use some kind of Loctite on the tapers, along with a key..Takes a good bit of heat and a puller to get the hub off the crank...But they fit the bearings loose enough in the cases to use Loctite on the bearings ..Must be for easier assembly...
10-19-2004 | 08:17 PM
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From: cape coral,
FL
RE: re-timing magneto
Thought there might be a mechanical way I wasn't familiar with where I wouldn't need to run the engine. What I do now is use an electronic timing light connected to a 12v battery. The 12v battery ground must be connected to the engine. I then mark TDC on the magneto wheel and a mark on the case to align. Make additional marks on case or wheel at appropriate degrees (5,10,15 etc.). I found the stock homey at about 7 deg BTDC.
Thanks for all input, red
Thanks for all input, red
10-19-2004 | 08:57 PM
#9
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RE: re-timing magneto
While I do not know about your engine some Stihl engines have an advance built into the coil. By now they might even have an advance curve. There is a minimum cranking speed to generate a spark. The advance at cranking speed (also probably at idle) is different than the high speed advance. Also some of the kart racers are using offset keys to control the advance.
