atomic 4 carb leak

[gemstad]

I have an atomic 4 /zenith carb, late model fixed main jet. since it had sat on the hard for aprox. 5 yrs. I removed it disassembled it and cleaned it. this engine is in an alberg 30 and sits at an aprox. 15 degree angle. the carb is filling with gas and is leaking around the shaft that supports the throttle butterfly. I was told I need to tweek the floats to compensate for the engine angle. which will fully close the float valve. any thoughts ?

[Jammer]

I think it's farfetched to blame it on the incline. Usually the problem is that there is contamination or damage preventing the needle valve from closing properly on the seat. Moyer Marine sells the needle and seat for $21, or you can get a complete kit to rebuild the rest of the carb.

[RGN]

Jammer has the cure above.
Mine also leaked when I was first getting the boat ready for launch, the float valve just gets old, hardened and takes a set or cracks then leaks. Also the gasket between the top and the carb body can leak air into the carb causing running problems, just replace that to. you will need to know if it is a late model carb (Hahaha) or the earlier model. Late model has 5 screws.


Moyer Marine forums are a great resource and very helpful.

[a64pilot]

While I don’t have an Atomic bomb, I have some experience with older carbs.
First make sure the float doesn’t have fuel in it, if it does then tweaking it won’t work well, and replacing the needle and seat won’t help either, if it’s a brass float often you can desolder the vent hole, drain the fuel and resolder. Most often brass floats are of course two pieces soldered together, but there is usually a hole that allows air to escape during the soldering process that is soldered last.
The hard plastic floats have to be weighed as they get old they sometimes absorb fuel, but I assume you have a brass float?
I had to do this on an old aircraft carburetor that there are no parts available for, but it was an easy fix, I used soldering paste and it worked a treat.
Float level is very easy to check and adjust. Often times the needles will have a rubber tip, if they do and they are old this tip gets hard and often leaks, best thing to do then is replace it and the seat as a pair of course.

[AKA-None]

Don’t desolder the float. Use a pin vice and tiny drill. You don’t want heat if it’s got gas in it. Danger fire hazard

[Boatyarddog]

Originally Posted by gemstad

I have an atomic 4 /zenith carb, late model fixed main jet. since it had sat on the hard for aprox. 5 yrs. I removed it disassembled it and cleaned it. this engine is in an alberg 30 and sits at an aprox. 15 degree angle. the carb is filling with gas and is leaking around the shaft that supports the throttle butterfly. I was told I need to tweek the floats to compensate for the engine angle. which will fully close the float valve. any thoughts ?

Tough enviroment for any carb, let alone an updraft carb.
I've rebuilt lots of these and dirt and water contamination are the biggest problems.
I've also encountered warped fuel bowl bodies.
However, parts are available for rebuilds.
I do suggest that you install a fuel/water separator, if you don't already have one.
A small inline filter, is also recommended just after the fuel/water separator.
You may have dirt in the tank so flushing may help.
If your Alberg has a deck plate to fill the tank, check the o-ring on the cap to see if it's there or is cracked or damaged.
Usually the float sticks open enough to to allow the fuel pump to keep pumping the fuel in thus flooding the carb and drooling fuel everywhere.
It doesn't take much.
Good luck!
Cheers,
SV Cloud Duster

[Sailon1]

I recently cleaned my A4 carb and then had leaking problems--I lost
the small brass needle somewhere and that was the issue. This is an
obvious problem (perhaps) but worth checking, nevertheless.
As previously mentioned, Moyer Marine is the go-to shop for A-4.
You can call and ask for advice-very helpful-or join the forum and see
what the members might suggest. Good luck!

[ronstory]

If the jets are fine and you can remove them without damaging them, just grab a generic zenith carb rebuild kit. The latest version of the Zenith used for the A4 is #13355... but their a lots of parts kits for gaskets and needle valves.

Prices are $15-25 on Amazon or Ebay.

[gemstad]

thank you all for your input. I had recently taken the carb apart to clean it since it had set for aprox 5 yrs so I knew it was good on the inside mechanically, and I needed a fix right away, and not wanting to wait for parts I went thru a copy of the original manual. it suggested using a sharpened wooden dowel to polish the seat. figuring I had nothing to loose I chucked a dowel in my drill and did just that. problem solved. sometimes the simplest solution is the right one . again thanks to all who took the time to chime in .