Engine Cutting Out

[Unregistered]

I have owned a Tarten 27 for several years now with an atomic 4 and have finally realized that there is some consistency with a problem with the engine cutting out after approximately 2- 2/12 hours of use. Most often it doesn't get used for extended periods, but I believe at least over the coarse of the last 3 years it has been pretty consitent.

The engine cuts off without any warning and just goes completely dead, as if one had turned the ignition key off. In the past after a significant period of rest, maybe 1/2 hour to 1 hr, it will kick over again and seem to run fine (although we haven't had to run it long after an incident like this). It is hard starting in these instances, but until the last time, had always started up again. The last time we tried over the coarse of several hours to get it to kick over, but had no luck. The next morning it started up like a charm, like nothing was wrong with it at all.

We had an self proclaimed Atomic 4 specialist take a look at it and do some work on it. He was pretty convinced that the problem was either the coil or condensor, so he replaced both, while also checking distributor, plugs etc. He used parts I had as spares which were not too old and had obviously never been used.

This did not solve the problem as the next time we ran the engine for 2+ hours, it cut out.

One thing I've noticed on a couple of occasions, and may have consistently happened, is that when the engine starts again, the exhaust water is rust stained for a few spurts and then turns clear.

The mechanic felt that if this didn't solve the problem he would suggest looking into a fuel problem, rather than electrical.

This mechanic was someone we came across while out cruising and is not that close by, so can not take advantage of his skills. I'd like to know if you have any advice that I can offer to another mechanic who might be more local. I would certainly appreciate any infomation you can provide.

[Don Moyer]

Here's a list of things we compiled in a recent tech note to check in cases where an engine refuses to start. Presumably, if you can determine the reason that the engine refuses to start, it will be the same reason that it shut down in the first place. My guess is that you'll discover your problem
in the fuel or ignition section of the checklist:

1) Close raw water through hull as soon as it's determined that the engine is not starting within the normal time.

2) FUEL: Remove the flame arrestor and check for the presence of raw fuel. If the choke is closed completely, there should be raw fuel puddled in the bottom of the intake throat within 15 to 20 seconds of cranking (3 or 4 five-second attempts). If the carburetor intake throat is "bone dry" after this amount of cranking, the reason for the non-starting is either a problem in the fuel supply which prevents fuel from getting to the carburetor or some problem within the carburetor that prevents the fuel from getting through the carburetor (most likely a blocked main jet).

3) IGNITION: Remove the secondary lead from the center of the distributor cap and hold it approximately 1/4" from the cylinder head while someone cranks the starter. You should see a good arc between the end of the coil lead and the head that can be stretched to 1/2" or even 3/4". If you see no spark, the reason for non-starting is clearly within the ignition system, most likely a breakdown within the primary ignition circuit.

This quick check of the ignition system does not rule out timing issues. While the Atomic 4 has virtually no history of slipping out of time once the timing has been properly set, if the non-starting follows work that was accomplished on the ignition system, the timing should be rechecked.

4) COMPRESSION: With all spark plugs removed, hold your thumb over each spark plug hole to check compression as someone cranks the engine for a second or two on each cylinder with the starter. An Atomic 4 will usually
start if any two cylinders have normal compression as indicated below.

a. Compression sufficient to force past your thumb no matter how hard you press it against the plug hole would confirm normal compression of approximately 85 psi or above.

b. If you can hold your thumb against the compression, but not easily, a compression value of approximately 40 to 50 psi would be indicated, and starting could be problematic.

c. If you feel virtually no compression on any one of the cylinders, the problem is likely a stuck valve.

5) If all of the above checks prove to be satisfactory and the engine still won't start, the problem is probably somewhere within the secondary ignition system, downstream of the coil. The components within this part of the secondary ignition system are very difficult to inspect, but they are fortunately not very expensive so I recommend replacing them in the following sequence: plugs, distributor cap, plug wires and rotor.

Regards,

Don Moyer

[dtinder]

The long shot----intermittant failure of the oil pressure safety switch. Don can explain how to bypass this little guy. We found ours the hard way. This is a three person job: One guy (the non-smoker) needs to be able to generate 7-10 psi at the pressure end of the switch. Another guy needs to apply 12volts---and the third guy needs to apply the multimeter. If you are short handed---a simple continuity check across the switch will suffice. This check is done while guy no. 1 is huffing and puffing on the pressure end whilst guy no. 2 checks continuity. You can do this by yourself----hook-up the meter with some alligator clips-----and activate the "plunger" inside the switch with a stout paperclip. This will not confirm pressure related problems----but at least you can determine if the switch has reliable "on-off" capabilities. Another option is to call Ken @ Moyer Parts---but you'll miss all the fun. Good Luck--