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Lycoming 0-320 plugs
- Thread starter Slowpoke
- Start date
marshmaster pat
Well-known member
So if you gap them smaller will that help burn off deposits. I used to gap mine at 0.032 but the mags have to be hot for it to idle well. Some people say to gap them at 0.18. What does that achieve? A hotter spark or what.
Just curious.
Just curious.
cowboy
Moderator
Marshmaster,
Waterthunder explained it best in one of his posts some time ago.
The battery ignitions will have ample energy to fire wider gaps, regardless of rpm.
The magneto ignition systems do not produce the same amount of spark energy at the reduced idle rpms. Therefore they wont run as well at idle with the wider plug gaps.
Also, It is my opinion that to wide a gap will cause tough starting, and fouling issues during a prolonged idle. This will show up on mags that are getting tired. Theres plenty of that scenorio running around out there on many aircraft powered boats. Trust me I know from personal experience.
Don't get me wrong, theres nothing wrong with magneto ignition. It was designed to be simple, rugged, and reliable. They will fire wider gaps, and produce good fire at the plug. They were designed to run with resistor plugs, that are harder to fire.
If a magneto running automotive non-resistor plugs is healthy, it should have an easier time than it ever would running a shielded plug and wire harness.
Ever check out the slickstart mag starting booster? I got one for my shower of sparks mags, and that was the best money I've spent yet.
They make them for impulse coupled mags also, and I'm thinking about getting one of those for another one of our boats. They work.
Duckluv,
Next time I got the plugs out, I'm gonna try 15 on the bottom holes.
Waterthunder explained it best in one of his posts some time ago.
The battery ignitions will have ample energy to fire wider gaps, regardless of rpm.
The magneto ignition systems do not produce the same amount of spark energy at the reduced idle rpms. Therefore they wont run as well at idle with the wider plug gaps.
Also, It is my opinion that to wide a gap will cause tough starting, and fouling issues during a prolonged idle. This will show up on mags that are getting tired. Theres plenty of that scenorio running around out there on many aircraft powered boats. Trust me I know from personal experience.
Don't get me wrong, theres nothing wrong with magneto ignition. It was designed to be simple, rugged, and reliable. They will fire wider gaps, and produce good fire at the plug. They were designed to run with resistor plugs, that are harder to fire.
If a magneto running automotive non-resistor plugs is healthy, it should have an easier time than it ever would running a shielded plug and wire harness.
Ever check out the slickstart mag starting booster? I got one for my shower of sparks mags, and that was the best money I've spent yet.
They make them for impulse coupled mags also, and I'm thinking about getting one of those for another one of our boats. They work.
Duckluv,
Next time I got the plugs out, I'm gonna try 15 on the bottom holes.
cowboy
Moderator
Yeah,
My Dads 360 has a dual mag like yours, and he had to silicone the crap out of it. I've had a mag expert tell me not to be afraid of the silicone. He recomended doing the cap to case area, as well as the p-lead "ground wire" ports. Plug wire to cap won't hurt either.
Anyway, after he siliconed his, it stayed dry inside.
I don't think the vent will help clear rain water out very fast, but they do help stop the mag from having it's own little weather systems develop inside the case.
My Dads 360 has a dual mag like yours, and he had to silicone the crap out of it. I've had a mag expert tell me not to be afraid of the silicone. He recomended doing the cap to case area, as well as the p-lead "ground wire" ports. Plug wire to cap won't hurt either.
Anyway, after he siliconed his, it stayed dry inside.
I don't think the vent will help clear rain water out very fast, but they do help stop the mag from having it's own little weather systems develop inside the case.