Jboute, thanks, probably just the photo -- there isn't an indentation there. I just put arrows there to show a comparison of the diameters of the two floats.
The actual interference is on the fuel bowl, which isn't present in the photos, because you can't see that.
I suppose a pesron could sand down the new float so it didn't interfere and recoat it -- if you knew what coating could withstand gasoline, oil, and ethanol. I don't know what they use.
I will try the old float -- I don't know that there is anything wrong with it. I just replaced it as a matter of course when rebuilding the carb.
Just to clarify for anyone who may be confused by all of the above, I'm just going to try to say what happened in an orderly fashion here. Sorry about any repetition:
I did a lot of work to get this engine running again in August. It had not run in about 25 years I finally did get it going after replacing the magnetos, condensers, points, plug wires, rebuilding the fuel pump and carburetor, and fixing a loose cut-out switch. I also replaced the water pump impeller, and put new seals on the gearbox
I had taken the boat and motor out 10 times, over the last month, starting the motor without problems, but often ending after some runs up to a half hour, with a sudden failure of the fuel system, where the motor would bog down and fuel would pour out of the top of the carburetor.
I did not have ignition problems, I had a carburetor float valve problem, which is in the title of this thread.
The first time this happened, the problem was traced to a chunk of rubber which came from a brand new fuel pump sight glass gasket installed with the fuel pump rebuild kit. It completely deteriorated due to ethanol in the fuel. A replacement gasket worked fine. Since the gasket is located AFTER the fuel filter, the fuel filter could not have stopped this piece from entering the carb.
The second failure was traced to a piece of non-rubber organic debris in the fuel, probably inadvertently left in a line when reassembling.
There was no debris found in the third instance of failure, but I did notice that the new float's tab was catching on the new washer installed under the float needle seat. The tab was too long, or the washer was too thick, but there was clearly rubbing interference when I moved the float.
I thinned down the washer so there was no interference, and as usual cleaned all orifices with carb cleaner and blew them out with compressed air before reassembling.
This weekend the engine failed again, but the failure at first seemed different, because it had run fine, but wouldn't re-start. On all other occasions the motor would start fine, but bog down and spill fuel sometime later.
I did wonder this time if I had a new electrical problem, but on testing this wasn't the case, and again the fuel float needle was the culprit, proven when I tested the motor at home in the barrel. It had just occurred when I tried to restart, because I had squeezed the fuel bulb, and that had flooded the engine. This was NOT an ignition problem.
Today I took the carb out, and took it apart. And found no debris anywhere in the carb.
In testing it I kept the carb off of the engine, with the fuel bowl off, and connected the fuel line. I held the float up against the needle and squeezed the fuel bulb, and nothing came out. This was repeated with both new parts and old carb parts and all worked as expected.
The light bulb finally went off when I added the float bowl back on the carb and I inverted it. With the new float I could not hear the float drop every time I turned it one way or the other. Sometimes it did, sometimes it didn't.
If I took the float bowl off, you could clearly hear the valve work. But it was iffy with the bowl on. Sometimes it opened, sometimes it moved, sometimes it didn't.
I then tried it with the old float. It always worked with the old float -- with the bowl on or with the bowl off.
I then compared the two floats. The new float was a little thicker and wider than the old float and I could also see what looked like a faint wear mark on the fuel bowl where the new float rubbed.
So, I'm not sure why I'm still getting responses about the ignition system, or mention of using a very small amount of seafoam two months and several tanks of gas since. AND the carb and fuel pump were rebuilt well after that, and new hoses were put on, along with a new inline filter, and the carb cleaned several times since.
I'm not sure what metrics are going to prove out the problem, but it's obvious to anyone actually holding this carb in their hand that the float is hitting the fuel bowl and getting stuck.
