Join Date: Feb 2000
Location: Annapolis, Md
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Re: atomic 4 mini explosion
Also, if the timing is too far advanced the engine can backfire through the carburetor. It sounds terrible, can make lots of smoke but its at least less serious than an engine rebuild. My comments are predicated on the probability that this engine does not have an updated ignition system.
The statement, "But it sounded very irregular thhe whole time, and more so as the sail went on. eventually the motor just went out of control, screaming, making crazy noises of things breaking down and propellers spinning hubs and all kinds of craziness, " seems extremely unlikely but not imposible. But in any event you are describing a wide range of symptoms that could result from all kinds of causes.
For example, the combination of an engine going out of control and the 'propeller spinning hubs' sounds more like badly adjusted controls so that the throttle was not backing off, and the transmission was not fully in gear. This is simple top diagnose and repair.
There are a whole host of things which could make the engine display the symptoms that you descibe. Without being there its hard to say what the actual cause is. My initial sense is that this is a problem with the ignition system but can't say whether the points are fried or improperly adjusted, the points mounting plate is loose and needs replacement, the distributor cap is cracked, the distributor clamp is loose and the distributor has been left free to rotate, whether the coil is on the way out, whether points cam is worn past its 'use by date', whether the timing gear is shot or improperly timed, whether there is one cylinder that is not reliably firing eventually flooding and so on. It is also possible that the engine is running rich which can also cause backfires, or lean which could cause run on and foul smelling smoke on shut down.
The carboned-up problem that was mentioned is also a possibility.
But, Properly maintained Atomic 4's are amazingly reliable and easy to maintain, but they take basic maintenance and enough knowledge of engines to quickly diagnose when something typical of these engines does occur.
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Curmudgeon at Large- and rhinestone in the rough, sailing my Farr 11.6 on the Chesapeake Bay