So I finally was able to get my 4378 zephyr (early ’46 model) to run for a while the other day. After running it for a while I began to notice some problems. First it was flooding out at low speeds no matter what I would do with the mixture adjustments. I am assuming something got sucked through that is making the float stick open so I will have to take that back apart. I noticed though that the gas cap has a hairline crack in it which was allowing a small amount of fuel to leak out of it. My question comes with this wondering how the internally vented tank works. I am assuming that it has to be a completely air/fuel tight tank in order to create a vacuum when the vent is closed via the carb so with the gas cap being cracked I am not getting it to seal up tight. Would that crack be the cause of my engine leaking fuel even when the carb is in the off position? I would think that I have a combination of that with the float sticking but wanted to check.

On a positive note it did run! 😮 This little guy has given me some fits so it was sure nice to here it sing for the first time in who knows how long. These little four bangers sure do have a unique sound especially at idle. I rebuilt the lower unit just before running it and it was pumping water really well! I will need a new prop shaft seal because there was fishing line wrapped around it which ate away at the seal a bit so I got some grease to leak past it while running it. Anyone know where I can find one of these? I will attach a video of it running in the tank but note that I did not have the prop on it so that I didn’t blow out all of the water and the exhaust tube was soaking to try to get the carbon build up out of it so she was a little loud. Thank you to all that have helped me get this far with this little motor and for all the help that I continue to get from this site. 😀