Flooding

JBohannon

Senior Member
I have had a little trouble with my A flooding mostly because I do not shut the gas off at the carb after I shut it down. In fact most of the time I shut the supply off and let it run dry before I cut off ignition. My question is when it does get flooded the motor will barely turn over or will not turn over without charging up my battery or jump starting it. Although I do have a battery tester that says it is ok. What could cause this problem.
 
These starters can draw a lot of current.. Have you ever checked the starter draw?? Even then all the connections have to be nice and clean and tight.. As long as the starter is run to clear the flood,, it can get pretty warm and draw the battery quickly..
 
If it only does this after the engine is warm it could be timing. If the timing is slightly advanced, it will cause the starter to buck and kick back. It will sound like the battery is weak and the starter is struggleing. Check points gap and timing. If the timing is way advanced it may do this even when its cold.
 
If you are running a stock configuration (updraft Zenith or equivalent) there is no excuse for flooding. Doing so usually requires a combination of over choking and a weakness in the ignition system.

Now, as far as the slow turning of the starter there can be several contributors. First is a weak battery. What kind of test are you doing? It needs to be load tested and I believe you will find it's bad. Other issues revolve around resistance in the battery connections (including poor ground and undersized battery cable). However this will not drain your battery unless you are talking about cranking it for several minutes.

From your description your battery is draining quickly which takes us back to the bad battery suggestion. If you are running a down draft carb and actually flooding it enough to raise the compression you have more serious problems that would include rinsing the cylinder walls and diluting your oil in the crankcase.
 
If it only does this after the engine is warm it could be timing. If the timing is slightly advanced, it will cause the starter to buck and kick back. It will sound like the battery is weak and the starter is struggleing. Check points gap and timing. If the timing is way advanced it may do this even when its cold.

Yep, good call.
 
I did load test the battery. I have an inexpensive tester but battery seems ok. I have been careful on my connections but I do see some corrosion on the positive ground terminal. I am using a standard updraft carb. Someone mentioned that if you get to much gas in the cylinders it washes the oil off cylinders and makes it hard to turn over. Is this possible. Also how big should the vent hole in my tank cap be. Has nothing to do with flooding but just curious how that little hole can let enough air in.
 
It was not my intent to suggest rinsing the cylinders clean of oil would contribute to the problem at hand as it shouldn't. I was just saying it's bad for the engine. That would take some doing with an updraft carb.

It still sounds like a bad battery since it doesn't hold up. The only other thing would be the starter drawing excessive current which I've never seen. Maybe Tom Wesenberg could chime in on that one. Take note of the post on advanced timing. However NONE of these things should kill a GOOD battery in less that several minutes in my experience.
 
About the only thing I can think of to add to what's already been said is if the starter bushings are worn to the point of the armature dragging on the field pole shoes, maybe the heat expansion is enough to make them drag a bit more. I'd check the timing first or a good load test for the battery. You could check the battery voltage while cranking the engine, or trying to crank it. Also take an amp check for starter draw. I'll post a picture of the inductive ammeter, which is handy for quick starter and generator amp checks.

c3557e16.jpg


Here is a picture of an inductive ammeter typical of what you can buy today at most auto stores or from the tool truck, such as Mac or Snap-On. It's in a plastic case about 2" by 3/4". There are two recesses on the back where you lay the meter on the wire or starter cable. The starter cable lays along the top side on the rear, and the generator wire lays across the rear near the bottom, by the pivot point of the needle. Sometimes these can be found for a few dollars at swap meets. It seems these and vaccum guages aren't used much these days, but both still serve a very useful purpose. I also have an old inductive ammeter that is in a metal case with a glass lens.
 
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With the problems you're having flooding this engine, I wonder why.. Whether you do or don't shut off the fuel when the engine isn't used should have nothing to do with the flooding problem.. I'm just wondering if you're properly starting the engine..
 
If it only does this after the engine is warm it could be timing. If the timing is slightly advanced, it will cause the starter to buck and kick back. It will sound like the battery is weak and the starter is struggleing. Check points gap and timing. If the timing is way advanced it may do this even when its cold.

Purdy,
THis is something I've wondered about for a long time. I remember in high school you could always tell the kids who had gone for a cheap hopping up of their motors by advancing the timing--their cars would barely turn over when the motor was hot.

Can you explain why this is? First, why does it turn over more slowly, and, second, why is it so much worse with a warm motor?

My guess for the first is that the premature ignition has the combustion actually pushing the piston back down before it gets to the top of the compression stroke, EXCEPT it doesn't sound like it's firing at all. Does the tighter fit in a warm engine cause the second effect? Doesn't sound very plausible to me because the effect is so dramatic and the cars don't particularly overheat otherwise.

Thanks!

Steve
 
Steve, I think that you've got it right on both counts. You are correct, it doesn't seem to fire. If timing, is the problem, you can cut the switch off and the starter will turn the engine as normal. I didn't think to mention this yesterday.
 
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