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Message |
    
miro forest
Senior Member
Username: miro
Post Number: 1118
Registered: 11-2001
| | Posted on Monday, February 08, 2021 - 12:15 pm: | 
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Last autumn, I took a really good look at the timer contacts on the
2 cylinder St Lawrence in the fantail launch.
I've had it running now for about 3 years and I use it every week during the warm months.
I have a swing timer and the contacts are behind the flywheel and are not easy to access.
You can see the cramped quarters around where
the contacts are here:
http://www.oldmarineengine.com/discus/messages/4/423676.html
I cleaned the timer contacts up and in fact
replaced one of the slugs in the timer
"cartridge" and having done this once I
wasn't keen on doing it again.
So , how to keep the timer contacts from wearing
away? One of the sources of wear is the small
arcing that happens during running and over time
this ain't good. I figured if I could reduce
the current through the contacts, from about
1 to 1.5 Amps to say less than 100 mA,
it would help.
You can see the "theory" in the attached sketch
where I use a small relay in between the timer
contacts and the ignition box. The relay draws
about 85 mA . The internal contacts in the small
relay are good for 10 Amps - more than OK for
the ignition box.
Now my engine is 2 cylinder, so I needed to make
2 of those relays . The pictures show the relay
box I made up,using knurled brass buttons ( see
what happens when you get "COVID-bored" ) to make
the connections. If this fails while I'm out on
the lake I can easily revert back to the original
set up.
Now all I have to do is wait until the ice melts.... miro |
miro forest
Senior Member
Username: miro
Post Number: 1119
Registered: 11-2001
| | Posted on Monday, February 08, 2021 - 12:20 pm: |
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Engines that do not have the swing timer i.e. have
the timer driven by a 45 deg gear, can easily access
the timer contacts to clean / repair them. |
Chris Spring
Senior Member
Username: chris_spring
Post Number: 95
Registered: 02-2019
| | Posted on Friday, March 05, 2021 - 12:17 pm: |
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Interesting. This isn't an issue with the Adams, but I think you're on to something.
Good luck with it.
Cheers! |
miro forest
Senior Member
Username: miro
Post Number: 1162
Registered: 11-2001
| | Posted on Tuesday, October 26, 2021 - 03:45 pm: |
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I tried this out - took several swings at bat - but it didn't work out at all.
I think there's a dwell time issue trying to activate 2 relay coils tip to tail. Sometimes it works, and sometimes it doesn't.
I wouldn't call this a success and have put the idea on the shelf for the time being.
miro |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 1461
Registered: 07-2002
| | Posted on Tuesday, October 26, 2021 - 06:50 pm: |
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Miro, one problem could be that the relay points don't pen far enough drawing an arc and disturbing the ignition. Try a capacitor across the relay points and see if it helps. |
miro forest
Senior Member
Username: miro
Post Number: 1163
Registered: 11-2001
| | Posted on Tuesday, November 02, 2021 - 10:24 am: |
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JB that is an excellent point - I should have picked that up, but then I am too close to the problem to see it.
It will have to wait till next year, because we've had snow here and I kept the boat going as long as I dared this year - too much fun.
But it's now all buttoned up, high and dry for the winter.
miro |
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