Row Boat Motor Magnetos

[Buccaneer]

quote Richard A. White:

10 degree lag????

it should be firing before TDC…not at…
Make it stupid, retard the timing…LOL

Just guessing but I know of no engine that fires right at TDC, all that I know of are BTDC, how much depends on the set up…

Impulse magnetos are set up to fire at TDC, and are mostly found on tractors that
you "may" need to hand crank. It’s no fun cranking a tractor and having it fire
before top dead center. The "kick back" can really ruin your day. 😯
I believe the 10 degree lag means that the magneto stops turning for 10 degrees
while the spring in the impulse coupling "winds up" , releases, and zips the magneto fast
to make a nice spark. Once the engine is over 200 rpms or so, the timing should
be a fixed 10 degrees BTDC.
I’m sure someone will correct me if my understanding of the above is "all wet".
But at least now I can blame it on the Pot smoke in Canada drifting south 😆

Not sure impulse coupled mags are meant to be on RBM’s, but mine won’t spark at low speed
without the impulse coupling in place.
I watched some YouTube videos, but could find no RBM’s with mags. 🙁

Prepare to be boarded!

[The Boat House]

• This reply was modified 5 years, 5 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[Buccaneer]

Tubs, nice to see "smoke" on your RBM…. hope to see the same some day!
I wish I could put your video in "SloMo". Are you pulling the flywheel
through compression, or is it bouncing off reverse compression?
Also, where is the spark advance set during this process to "help out".
I’m not sure I’m man enough anymore to pull this Wisconsin through
compression, and realize after I thought of using both hands, that
it won’t be an option after the gas tank is back on, due to clearance
for the pinkies.
Thanks!

quote Tubs:

quote :

https://www.youtube.com/watch?v=IjGK5JwtKWk

The Super Elto’s timer along with using a battery is the
reason they start by bouncing them off of compression.
You will need to pull yours through compression as the
mag makes the current. You’ll want to start with the
flywheel back as far as possible to get a full charge in
the coil before the points open.

Prepare to be boarded!

[RICHARD A. WHITE]

http://www.rebuiltmags.com

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[The Boat House]

• This reply was modified 5 years, 5 months ago by The Boat House.
• This reply was modified 3 years, 2 months ago by The Boat House.

[Buccaneer]

Thanks Tubs. Maybe tomorrow I’ll see if I can rig up a temporary
gas tank and see if I can get the beast to pop a few times.
The poppet valve in my carb was missing the spring,
so I had to "guess" on a spring with the correct tension.
Also the poppet valve stem is pretty loose in the guide,
so that may have to be addressed some how.
The poppet valve does bounce when spinning the flywheel,
so maybe it’s okay for now.

Prepare to be boarded!

[RICHARD A. WHITE]

I got a hold of the people I gave a link for, they do not able to help..bummer

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[jimparrott]

Buccaneer,

Make sure you have a kill switch hooked up to the magneto in case it over speeds. Slow turning 2 strokes are controlled primarily with timing. I would suggest that you start out with the timing 10-20 degrees retarded and advance as needed. You fuel mixer dosn’t appear to have a throttle control so it won’t be much help in trying to slow it down. The stem being sloppy shouldn’t be much trouble as long the valve is seating. Sounds like your spring will be fine since it’s opening. As Tubs stated pulling thru compression is the way to start it. Bumping against compression is more of a buzz coil battery ignition setup starting procedure. If planning on running on a boat you will need to be able to adjust timing while running. I would suggest finding a magneto that is adjustable, or converting it to a battery buzz coil type ignition system.

Below is a link to a engine I have, that by design of the make and break ignition system cannot be retarded past TDC. In order to run it without a load, the throttle in barely opened to keep it from overspeeding. Restricting the air this much, causes it to cycle multiple times between firing.

Jim

https://m.youtube.com/watch?v=EI0k5zaj4X0

[jimparrott]

My friend JB was given an engine at a show that was missing major parts. We decided to start it with minimal fabrication efforts. Having a buzz coil ignition system is a handy tool to have. We simply used some rigid house wire and a bolt to fabricate a make shift timer and a fuel wet rag for a carburetor. In a short time we were able to fire up this old marine engine.
Check out the short video below.

https://m.youtube.com/watch?v=8oc5fHoOlJM

[Buccaneer]

quote Richard A. White:

I got a hold of the people I gave a link for, they do not able to help..bummer

Richard, I emailed the mag rebuilder, but as of yet, received no reply.
I wasn’t looking for a Elkhart mag, as even if he had one, I’m not into
buying "rare antiquities". Just looking for answers as to what other mags
may be a better replacement, etc.
Thanks for trying.

Prepare to be boarded!

[Author]

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