Gees, I think there ought to be a weekly award for dumb-a**ed mistakes, weird problems and frustration for the Atomic 4 marine engine community.
We're a weird bunch of boaters who like these old gas engines, which for their size have lots of power, are quiet and generally fairly dependable if kept up. Don Moyer at Moyer Marine
is a great resource and have bought stuff from him for years now. I have his original newsletters for 1994! What a nice guy, happy to talk to his customers and help them, he has an on-line forum
Anyway, I humbly submit myself for this week's dumb a** award.
I've been busy this winter doing a bit of an overhaul on my AT4 in my Islander 28 sailboat. Replaced a cracked head, head studs, put in studs on the water jacket plate, r/r the carb, etc. Still need to replace the rear seal. The engine was running fine prior to my work.
I replaced the coil as part of the process, even thought the old one was working fine. I have an Ignitor magnetic ignition and consider it probably the best engine upgrade I've put in.
After replacing the wiring, I couldn't get it to start. Checked the plugs and have lots of fuel. Found that I had inadvertently put the main ignition + source on the neg terminal of the coil. Switched it and still wouldn't start. Checked the spark and there wasn't any at the plug, nor from the coil to ground or distributor cap. Hmm, must of fried the $60 magnetic ignition. Drove home to buy part. (I keep it in Blaine, WA, about 120 miles north of my home in Seattle.)
To continue the above saga of woe. I drove back up to the boat. Jump on the boat with a new Ignitor part. Pull off the distributor cap and install it. Replace the rotor, but didn't put it FIRMLY into the camshaft. Tried to start, but of course the rotor was free spinning. Scratched my head for 1/2 hours, then found the rotor problem. Ha!
Except that in replacing the cap I managed to get the @#**& red wire stuck under it and shorted out another Ignitor. Poof, smoke, $60 gone.
OK, I'm gonna get this beast going one way or another. I pull out the old (like 10 years) distributor plate with points and condenser. Install it. Cannot get it to start. Move wires around on the distributor clockwise one hole, and she starts!! Whoohoo happy dance! Runs great, idles great. Warm it it up, stop it, torque the head bolts. Restart and warm up agian.
Shift into power and it stalls. Restart, apply some gas, shift and she runs, but it has a rhythmic power up and down, doesn't change when I adjust timing, etc. Shut it down and re-torque bolts again. Pour whiskey and scratch head.
Next morning I put in some new fuel and dryer. Check carb bowl, gas very clean, no problems (the carb was just cleaned). Check compression, and its fine (95-110). Plugs look ok, except #3 has some dirt on it.
Call Don. He thinks I have the distributor in wrong. OK, tells me how to make a TDC timing mark, align the distributor, etc. I do so, find that it's 90 degrees off, makes sense, even find an old timing mark. All's good.
Go to start and nada. Nada damn spark. Nada off coil wire, etc. Numerous calls to Don, VU meter tests, try to trace it down, etc. I show juice to coil, from coil, juice and continuity at the distributor, good ground everywhere, etc. I even tried another coil and replaced the condenser. I get juice up to the points, can even get a spark from them to the breaker plate, but no spark when I push the points apart, with ignition on, or when I crank. No spark from main coil wire either when I crank while holding the wire to the head (although I did get a spark from neg terminal to head when cranked).
I worked on it for hours yesterday, wore poor Don's ear off and gave up. I have no idea why it would run one time and not the next, again all wires are fine, new coil, new plugs, new condenser, points (they looked ok, and I got continuity). Wires checked for continuity.
I guess my plan is to go back up with yet another Ignitor system and install it. But I'm not sure why I'm still not getting a spark from the coil. Some little thing is not making contact or acting intermittent, I think, but damned if I can find it.
Your humbled mechanic of sorts...