Hi Lee, having had an Atomic 4 for 15 years, I can say the 2nd video sounds largely normal once you got it starte. So, it seems yo tell me compression is OK. The first one sounds a little rough, like a fuel issue. That could happen if the engine was run all the way out of fuel ans you had limited filtration of the gas. At any rate, out of an abundance of caution, I would do the following:
1. Get a compression gauge and check for even readings across all cylinders. 2. Clean the fuel strainer bowl. 3. Overhaul/clean the carb. You probably won't even need gaskets, and they're simple to do. Just be sure that you take photos as you take it apart and count the number of turns as you remove the adjustable jet(s). Tighten the counting the turns, and when you put them back in, go to tight and back out the same number of turns. 4. If you don’t have one, put in a fuel filter/water separator. It doesn't need to be a racor, one with a spin on filter (about $25) is fine. 5. Convert to electronic ignition. Moyer has a kit, but the same model is available elsewhere. Replace the cap and rotor while you're in there, as well as the plugs, which are Champion RJ12Cs. The cap, rotor and plugs are available at auto parts stores once you look up the Delco numbers. 6. Replace the raw water impeller. If the engine sounds weird to you, it may be the engine isn't pumping water through it like it used to. That is a wear item and should be replaced every 2 years anyway. 7. Add StaBil and SeaFoam to your fuel. A dose of Marvel Mystery oil doesn't hurt either. 8. Carry a spare coil. Once you go to electronic ignition, you'll probably never need it, but it is a potential point of failure. They're very dependable engines once you know what makes them tick (or not). Bruce Whitmore 1994 C&C 37/40+ "Astralis" Madeira Beach, FL (847) 404-5092
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