How Long Can an Engine Be "Flooded" For? Is 12 Hours Too Long?!!

A couple thoughts -

1) check to make sure the plug is wet - i.e. it's getting fuel (probably not the problem given the gas smell, but you never know)
2) check the level of the oil in the crank case - and the texture. Is it over full?
3) fiddle with different configurations of the choke
4) try it with a little shot of ether - can you keep it running?

What these things tell you - if you can't start it with ether, it's a spark problem. If you have a wet spark plug, it's at least getting some gas (also the second half of (4). Now it's a mixture problem. Does it have a fuel filter? Is it clean? If your oil is 'over full' (and pretty thin) you're running way rich, and the excess is filling the crankcase.

When it started with ether, did it smoke (black)?

Now the the lotto guess - I'm guessing the float in the carb crapped out on you. Partially because of the description, partially because I've had 2 croak in the last year (different old Tecumseh motors). Good news is (assuming you can get the carb off) it's a dead simple repair and the rebuild kit is $6.

Steve

ThePhotoHound said:

Steve -

First of all, thank you so much for your in depth response. I will certainly check all of those things when I get home (and will post my results around 6-7 PM). In answer to your question, when it did start (first pull), yes, the smoke was black.

I have only worked on older engines... where do I spray the ether on this one?!

I will check on the fuel filter.

What exactly is the standard choke setting for starting this engine? Closed? Open? I would assume it's completely open, then once it starts to run, close it down to about 1/2. This has worked for me in the past. How about the idle lever? All the way up all the time?

Also, if I am getting gas in the crankcase, what is the underlying cause? This is actually happening to my other Tecumseh 8hp (on my rototiller). My father in law borrowed it (and tried to fix it by taking the carb apart and cleaning it) but to no avail.

Click to expand...

The starting fluid goes in the same spot - the intake throat of the carb. It's a small engine, use only a little. Gas in the crankcase means that the carb float valve is leaking, the fuel is filling the cylinder and then draining past the rings into the case. The choke should be closed when starting cold and opened fully when the engine is warm enough to idle at normal speed. The idle air valve setting may depend on the engine but try full throttle at first. To clear out a flooded engine open choke and throttle to max for several engine rotations (or more) then set back to starting positions. If that doesn't work pull the plug.

I bet if you've been running it consistently at half choke, it's probably filled the crankcase with gas, maybe fouled the plug. You should always get the choke full open as quick as the motor will let you.

If it's like most Tecumsehs (little round paper filter) you can shoot a little ether right on the filter.

Steve

Really can't say with certainty from here, but it's way more common for the choke to be a lever. There's almost always a little picture of the choke (two vertical bars with a damper in between) next to the lever.

Post a couple picks if you need someone to walk you through it.

Steve

I think from your description the tube that goes up and down in the carb throat is the mixture control. Is it threaded? If so, I think I'd adjust it to the mid point of it's travel and see if you can just get the thing to keep running. once it's running, you're close. Open the choke up all the way, and thread the tube in and out until the motor runs well at idle and at full throttle.



Steve

Engines run on fuel mist not liquid droplets. You might not see a wet plug until you have way too much liquid fuel in the cylinder.

Can you repeatedly start the engine on starting fluid? If so then that leads me to believe that the carb isn't working. It is odd for it to be working one hour and not the next though. Did you do anything else in that 2 hour time frame such as put more fuel in the tank?

When you cleaned the carb, did you blow through any of the very small fuel passages that go from the bowl to the carb throat?

A spark can be weak. I tend to not believe that yours is strong enough to run with starting fluid yet too weak to ignite fuel mist. I suppose it is possible though. With the plug out, pull the cord and see how far the spark can jump to the head. (Don't shock yourself) Then attach the plug to the wire, ground the plug on the head and see how strong of a spark you get between the plug's electrodes. The spark should not be faint. If it's at all suspect, clean the inside gap or even better, buy a new plug.

It can be rough on the engine but you can try to keep the engine running with starting spray for a little bit. You can also try to keep it running with well timed primer shots. I've heard that propane from a small torch will work also but I have not tried that myself. After a minute or so of 'life support' there's a chance it could magically fix itself.

How do you know there was plenty of compression? Did you use a gauge?
If not, a parts stove like autozone will probably loan you one.

BTW, in your picture, the left shaft is the throttle valve, the right shaft with the spring and detents is the choke.

wd-40 is easier on the engin then starting fluid and works just about as well

Yes WD-40 1000 and one uses

Incidentally this just happened to me literally 10 minutes ago:
I had some older fuel in a 1 year old lawn vac so I ran the engine last night until it was dry. This morning I fill the tank with new gas and I notice fuel running out the air cleaner. It turns out that the needle valve stuck open when the engine shut down from lack of fuel. Two taps with a screw driver and it reseated itself. Engine still wouldn't start and the plug is wet from the extra fuel in the cylinder. I wire wheeled the end of the plug, sand papered the inside of the electrodes and blew it out with compressed air.

Choke on, throttle on, starts right up. Hopefully it'll start up this afternoon when the buyer comes to look at it.