Zenith carb rebuild

[marty in Ohio]

Have rebuilt the carb on a friend's Zenith. Runs well until he stops and then the gas runs out of the carb. I know this has been discussed here many times, but I can't seem to find it on the archives. Any ideas?
Marty

[30 Closed Cab PU]

If you do a search on leaking carb, tons of info, almost too much.


Causes I've encountered/heard of.


Bad float valves (even new ones, sometimes takes 2-3 valves to get a good one).

Jet heights not set properly.


I've had poor luck with plastic float shims, prefer the fiber ones.


Poor sealing on the float valve threads.


Leaky float.


Wear on the float where the float valve sits.


Have seen too high of float valve height causing a leak.


Check for interference between the float and the carb, have heard that some floats are a little different dimensionally and hang up/rub on the carb.

[Gary WA]

Originally Posted by marty in Ohio

Have rebuilt the carb on a friend's Zenith. Runs well until he stops and then the gas runs out of the carb. I know this has been discussed here many times, but I can't seem to find it on the archives. Any ideas?
Marty

Rebuilt many carbs myself, sometimes the Repo gasket between the halves is wide and the float will hang up on it I usually trim it back. As soon as it happens,stop remove gas line from carb to verify if gas is getting to it. Then go to carb if ok.

[johnbuckley]

Zeniths: Causes of leaking...
Problem: Remedy
1 Leaking/loose float valve gasket: Tighten/reseal/replace
2 Leaking float valve: (or crud stopping it sealing) Replace ( or clean up if poss))
3 Friction on float hinge: Loosen
4 Incorrectly set fuel level: Re-set
5 Hole in float: Repair or replace
6 Too many gaskets on main jet Check
7 Cap jet or main jet too short: Replace
8 Leaking/loose gasket at main jet: Tighten/reseal/ replace
9 Leaking /loose gasket at cap jet: Tighten/replace
10 Leaking or loose GAV housing threads: Tighten/ reseal/ replace
11 Leak at fuel inlet union: Tighten/reseal/replace
12 Loose/leaking gasket at strainer: Tighten/reseal/replace
13 Loose/leaking gasket at drain plug: Tighten/reseal/replace
14 Cracked housing/leaking passage plugs: Repair or replace

1-7 will generally manifest as poor running.
8-14 will generally not affect running unless there is excessive leaking.

[marty in Ohio]

Wow, good responses all. This gives us a lot to look for as we take the carb apart to check.
Thanks everybody,
Marty

[30 Closed Cab PU]

Sponsored Links (Register now to hide all advertisements)

If it also leaks with the shutoff off, you have got an additional issue with the shutoff, but this usually happens over a longer period of time.