I sprayed off the radiator after mud ridding one day, and some how I think some water got in the engine 400, because I took off the air cleaner and I saw water droplets on the carb butterfly choke. I got it to start, and it ran ok at idle once it started, but any kind of gas made it shake and die.
Now it won't start at all, I'm guessing it's electrical, but I don't know what else it might be, because I replace spark plugs and wires, distributor cap and rotor.
It turns over easy, and then a burst of gas vapors come out of the carb and then the engine back fires.

Anyone have any suggestions on this?

 

Duraspark? Did you spin the engine with the plugs out and try to clear what got in? Any clue how much water is still in it? All else I can think of is there might be some water somewhere in the ignition connectors, perhaps WD-40 'em, dielectric grease, and try again. Is it making decent spark during cranking?

 

You might want to check the timing. The 78 I used to have (also with the 400) had a similar problem. It turned out the timing chain was shot and had jumped a couple teeth.

 

No I didn't try turning the engine with the plugs out, but if there is any water there isn't to much, but while turning the engine if there is water in there will some come out?
I tryed useing starter fluid on some of the things to evaporat the water that might of been there, and that didn't help either.

It sounds like it has plenty of spark.

Also, how much trouble is it to take the timing chain cover off? I'm just wondering if I'll have the room to do the work, with out pulling pumps and other things off the get to it??? But I'll look into that, but it was runing the day before without ANY problems, so I would think it would of ran rough at least for a little while if it is the timing, but not sure.
Thanks for the help so far, keep it coming,
Matt

 

Matt, The timing chain on mine went without any warning. I drove it home from work and the next morning I had trouble getting it started. It idled very rough (sounded like it was only running on a couple cylinders) then stalled and wouldn't restart. It turned over easily enough, but would just cough and backfire through the carb.

I didn't attempt the job myself since I didn't have the time or place to do it... if I remember, it cost me around $300 to have it done by a good friend who owns a shop. This was a little over 2 years ago...

 

Have you removed the distributor cap and blown it dry with a hairdryer ?

 

In what way? The only way I know of to hear plenty of spark is if the engine is running. Otherwise you need to test by pulling a plug or using a spare plug and grounding it while cranking. I'd bet money you have moisture under the distributor cap. This is VERY common when cleaning an engine. Pull the cap and let it dry or better yet, as already posted, spray WD40 in there as it will displace the water. If you try all that and recheck the plugs and find you have no spark then I'd take a look at the Duraspark box. They don't like too much water.

 

Check for dirt in the carburator. Also, make sure the fuel pump has finally died and the the fuel line doesn't hav any vapor lock in it.

 

Any chance you blew off a manifold vacuum line with the hose? If it starts and idles, try putting a hand over the carb to seal off most of the air coming in. If the engine rev's, you've got a vacuum leak.

I don't think you really need to pull off the timing cover to get an idea if you jumped teeth. Here's a couple things I would try.

1. Pull out #1 plug and rotate the engine (I suggest with a ratchet and socket on the crank) and slowly bring the piston to TDC on the compression stroke. If you're real careful, you can put a small screw driver in the spark plug hole to feel the piston coming up and then get real close to TDC. Once you're at TDC, check the position of the timing mark on the harmonic balancer, then pull off the distributor cap and inspect the position of the rotor. Timing mark should be at TDC (0 deg), rotor should be pointing a little past #1 position (what ever your timing value is 8-10 deg).

2. With the same ratchet on the crank, once you're close to TDC turn the crank clockwise and counter-clockwise. Watch the rotor in the distributor while you're doing this. If the timing chain is tight, the response should be direct - every move in either direction = movement of the rotor. Should the rotor have a pause going from one direction to the other - start planning to pull off the timing cover. This assumes there is enough slop in the chain to jump some teeth.

3. Something else to try, if you can get it to start and idle, is shine your timing light at the timing mark and watch for a while. It should consistently indicate the same timing. If it looks jumpy, well that's not good. Again, timing chain indicator. (I know this one is a little weak - combine it with one of the other tests.)

Having said all this, it sounds a little coincidental to me that you have timing problems only after squirting water. While it is not out of the question, I agree with the other posts about water having gotten into electronics where it shouldn't have.
Good luck!

 

Just one more thought too, double check your firing order. If you pulled the plug wires is it possible you got any of them mixed up? The gas out of the carb and back firing really sounds like the firing order could be goofed and you're sparking on your intake stroke on some cylinders. Just something to check on. Keep us posted.

 

I started spraying starter fluid down in the distibutor cab, down the carb, on the coil cap, and anywhere on the electrical I think got wet.

I then started it, and it ran real rough, so I sprayed a little more down the carb, and same thing, then I checked the spark plug wires and I had 2 mixed up so I fixed that and now it runs like a champ.
Thanks for all the help guys, I really thought it was the timing, but it turned out to be easier than I thought.

 

It was the timing - It was way off for two of the cylinders! Congrats, I know how good it feels to find out it was something easy after all.