Fuel problem?

[Cat 30 in SF]

I recently suffered from fuel in the exhaust manifold, carburator and cylinder heads. I followed your instructions very carefully and used liberal amounts of Marvel Mystery Oil (MMO) in the cylinder heads and then some more in the fuel. I manager to get the engine started and it seems to run great when it is running but I am having some trouble getting it started and am looking toward the fuel pump for a few reasons. The reason for the water in the engine was that the exhaust pipe blew a big hole and allowed water to enter due to the lack of positive pressure in the muffler. A lot of sea water got onto the fuel pump and safety switch. A few times when I turn off the engine I hear a tick, tick, tick coming from either the fuel pump or the safety switch. Since the carburator is not filling with fuel during this event, I think it is the safety switch. If I turn off the batteries the sound stops immediately but will come back on if I turn the batteries back on without letting things cool down.

The hard starting sounds like it is turning over but no real combustion until a little while and then it starts up. In another related situation, after running the engine for about 20 minutes at idle, I tried to rev the engine and it wouldn't get past 1300 RPM without choking and dieing. I think that was due to a main jet that was blocked (with some crud from the past water event) but has worked itself out. Now the hard starting problem remains.

Any ideas on what to do first?

Thanks

[rgoff]

If the fuel pump has power to it before you crank the engine, it's normal for it to "tick tick". It usually slows down as the carburator fills.

In a typical arrangement, the fuel pump wouldn't have power to it until you crank the engine. That's the purpose of the oil pressure sensor that controls power to the fuel pump as the engine is running. No oil pressure, no power. While the engine is cranking the power comes from the starter.

[rich@rlatvala.com]

I understand...

The problem is that it is ticking too fast and won't stop after the engine is off. Why would the carburator continue to run with the key out?

Rich

[Don Moyer]

Whenever an engine starts hard, but then runs OK after it starts, the problem almost always relates to a choke that is not closing completely. Because of the updraft design of the carburetor, it is normal for the Atomic 4 to require full choke for a quick and easy start.

Don

[Don Moyer]

Rich,

Your situation is very perplexing. I can only think of two possible "renegade" sources of power to the fuel pump with the ignition switch off: A short within the starter solenoid that would supply power to the pump from its "R" terminal, or from a defective diode in the alternator which would feed power back to the positive terminal of the coil, and on to the fuel pump.

The problem is that either of these malfunctions should also keep the engine running after the key is turned off, since power in either case is being supplied to the positive terminal of the coil.

I would start by removing the "R" terminal connection and see if the pump stops working. If it keeps working with the "R" terminal disconnected, disconnect the field flashing lead between the alternator and the positive terminal of the coil.

Please get back to us on this one, as I'm sure there will be quite a few of us pulling out our hair until we hear the answer to the riddle.

Don

[jkenan]

I had the same problem with my fuel pump ticking with the ignition turned off. It would happen intermittently, last for a while and stop. Then start again. It turned out to be a short in my ignition switch (probably due to seawater getting into it over a period of time). New switch, heavy application of anti-corrosion spray directly into it, and now several months later, nary an unwanted tick....

[Don Moyer]

Good for you, John! It didn't occur to me to suspect the ignition switch itself, since I would have thought that a short in the ignition switch would have kept the engine running. I suppose when you're dealing with an intermittent electrical condition, anything is possible.

Don