- Briggs and Stratton 3.5 hp lawnmower engine problem - 9 Updates
- Yamaha Stagepas 300 failure mode - 1 Update
| etpm@whidbey.com: May 26 09:57AM -0700 >> not. >> Eric >say hi to Darwin for me. Oh phooey. There is no way you can get a dangerous shock from slowly turning over an old lawnmower engine equipped with a magneto. Sheeesh! Eric |
| John-Del <ohger1s@gmail.com>: May 26 10:38AM -0700 > Oh phooey. There is no way you can get a dangerous shock from slowly > turning over an old lawnmower engine equipped with a magneto. Sheeesh! > Eric Exactly, on a small magneto like this it'll tickle, but this reminds me of a true story: Many many years ago, a guy I knew was having some ignition work done on his stock Hemi Challenger at my buddy's garage, and brought along a magneto to try just in case. Just rotating it a half turn sent him flying! Those things have balls. |
| etpm@whidbey.com: May 26 10:59AM -0700 On Sat, 26 May 2018 10:38:17 -0700 (PDT), John-Del <ohger1s@gmail.com> wrote: >> Eric >Exactly, on a small magneto like this it'll tickle, but this reminds me of a true story: >Many many years ago, a guy I knew was having some ignition work done on his stock Hemi Challenger at my buddy's garage, and brought along a magneto to try just in case. Just rotating it a half turn sent him flying! Those things have balls. Was the mag the type that winds up when being turned over slowly? I have some old magnetos that work this way. One is on my 1945 Gibson tractor. When turned slowly it winds up a spring inside that lets go when it reaches a certain tension, thereby spinning the magnet fast enough to get a good spark. Those mags will deliver a really good shock. Years ago I had one of these that would only deliver a little tingle. Talking to a guy who knew about mags said that the coil may have absorbed moisture over time, especially since the mag was from a marine engine. He suggested baking the mag in oven at 200 degrees for several hours and then letting it cool in the oven. I tried his suggestion but was dubious. After it was cool I grabbed the spark plug wire and turned the mag over. When it let go I got a really good shock. Made my arm ache. Eric |
| John Robertson <spam@flippers.com>: May 26 01:32PM -0700 On 2018/05/26 10:38 AM, John-Del wrote: >> Eric > Exactly, on a small magneto like this it'll tickle, but this reminds me of a true story: > Many many years ago, a guy I knew was having some ignition work done on his stock Hemi Challenger at my buddy's garage, and brought along a magneto to try just in case. Just rotating it a half turn sent him flying! Those things have balls. Magnetos were used as torture devices by the Nazis and other unscrupulous folks and guess where they were hooked up... John :-#(# |
| John-Del <ohger1s@gmail.com>: May 26 02:06PM -0700 > wire and turned the mag over. When it let go I got a really good > shock. Made my arm ache. > Eric No, just the type they used in race engines. Something like this: http://www.westracingproducts.com/MSD-Pro-Mag-12-LT-Magneto-Fits-Chevy-V8_p_981.html |
| etpm@whidbey.com: May 26 03:04PM -0700 On Sat, 26 May 2018 14:06:36 -0700 (PDT), John-Del <ohger1s@gmail.com> wrote: >> Eric >No, just the type they used in race engines. Something like this: >http://www.westracingproducts.com/MSD-Pro-Mag-12-LT-Magneto-Fits-Chevy-V8_p_981.html They must have some pretty strong magnets and the voltage at operating RPM must be VERY high. I guess that's what is needed for really high compression engines. Eric |
| Fox's Mercantile <jdangus@att.net>: May 26 05:52PM -0500 > They must have some pretty strong magnets and the voltage at operating > RPM must be VERY high. I guess that's what is needed for really high > compression engines. At one time, I had a '55 Chevy 2-door sedan. With a 437 cu in big block,Hilborn fuel injection <https://kinsler.com/Shop/wp-content/uploads/2016/11/BBC-X-ram.jpg?9a05f9&9a05f9> and other assorted"make a shit ton of horsepower" goodies. One of them was a Hunt Magneto. One day, while hanging out at a local wrecking yard, a guy bet me he could kill my engine by pissing on it. Heh. "$100 says ya can't." I opened the hood, by tilting the whole front end forward. He unzips his fly and I watch the golden stream arch over until it hits the distributor. My Chevy is still idling, and he's laying on his back screaming "My dick!" I just walked over to him, "When you're done screaming,you owe me $100." -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| Fox's Mercantile <jdangus@att.net>: May 26 05:53PM -0500 On 5/26/18 5:52 PM, Fox's Mercantile wrote: > At one time, I had a '55 Chevy 2-door sedan. > With a 437 cu in big block,Hilborn fuel injection Typo, 427 -- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com |
| captainvideo462009@gmail.com: May 27 06:57AM -0700 > I apologize if part of this seems off topic but I thought that the electronic component of it might be on. I have this 3.5 horse engine on my old push mower. The engine is about 38 years old now but the mower is used very infrequently so the hours are not that bad. About 5 or 6 years ago I replaced the old OEM coil that used points, with a used newer electronic type that eliminates the points. The mower is on it's third carburetor, gas tank and second deck but it has always started ok. I tried to start the mower this morning and as sure as my wife said, (I hate it when she's right), "You'll never start that old thing", it wouldn't start. Long story short there is no HV spark to the plug. It seems as though the coil is bad again. I was going to hit up a few used lawnmower places to try to get a replacement coil because I have no engine numbers on my machine to look up the part but I was wondering if anyone knows if it's possible to bench test these things. Thanks for any help Lenny I understand the value of "object lessons". I have 5 grandchildren. But why in God's name would you let someone piss on your engine? Lenny |
| owhatagoosiam@gmail.com: May 27 05:57AM -0700 > Sound cut off, replaced with low frequency hum (thus amplifier is still active), Limiter led (red on bar graph) stuck ON, Turning it off and after a few minutes back on solves the problem. > That problem was traced down to an 7915 voltage stabilizer on the main preamp/psu board, having an output of -8V instead of -15 on normal operation and after 15 minutes that voltage fell to 0 volts. Replacing the 7915 with another fixes the problem (solid -15V on output). My Stagepas 300 has an 7915 with plastic casing (too large heat resistanse to heatsink, I guess, and a semiconductor fatigue resulted to that problem). It looks that using a metallic 7915 is possible as the heatsink is electrically isolated from the rest of the circuit on my revision, if in doubt use some mica - plastic ring isolator there. > Cheers. Mak, Did you replace the 7915 chip yourself or did you have it done in a shop. I don't trust myself to make this repair but the cutting out problem has made the Yamaha unit totally unreliable so I really need to try it. Any tips would be greatly appreciated. Thanks J |
| You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com. |
No Response to "Digest for sci.electronics.repair@googlegroups.com - 10 updates in 2 topics"
Post a Comment