Scavenge Tube or not...

[Mo'o Moloa]

My engine has been running rich and doeas not idle very good. There was also fluid ( gasoline) dripping from the carb. I decided to remove the carb and rebuild.
I see there is a fitting on the manifold for a scavenge tube, but no tube. I didn't find a fitting on the carb, either. What I did find was a bit odd.


Is there supposed to be a scavenge tube there?



Thank you,
Jason

[hanleyclifford]

Looks like the fitting broke off on the bottom of the carb. I recommend you drill and tap and run that tube. It cleans up the drip which can be dangerous.

[JOHN COOKSON]

The #1 cause of gas dripping out of the carb is the inlet needle valve not sealing because A)it's shot or the seat is shot; or possibly B)a hole in the float which prevents it from floating up and sealing all the way.
To me it looks like someone just plugged the hole. But it doesn't really matter. The scavenge tube needs to be replaced. Coast guard regs require that there be a way to remove "free" gasoline from the carb.
Looks like you are up for a carb rebuild.
Do you have a fuel shut off valve before the carb?
A big welcome to the forum.

TRUE GRIT

[lat 64]

Aloha,

Get the tube installed. It is a safety device. Also, it's required by the coasties!

Russ (same time zone)

[BunnyPlanet169]

Originally Posted by hanleyclifford

Looks like the fitting broke off on the bottom of the carb. I recommend you drill and tap and run that tube. It cleans up the drip which can be dangerous.

It looks too coarse IMO - I would have said it looks like someone threaded or pushed in a sintered plug. Anyway, it shouldn't be there for reasons others have well stated.....

[joe_db]

That looks like a tractor carb with the drain in the bottom. That would be on a boat!

[Mo'o Moloa]

Thank you for all the input. This is my first atomic 4, so i'm still learning its characteristics.

[67c&ccorv]

Bin that carb and get a new one from Moyer...doesn't look like either a Zenith model 61 or 68 marine carb?

[sastanley]

Originally Posted by Mo'o Moloa

Thank you for all the input. This is my first atomic 4, so i'm still learning its characteristics.

Jason,
That's funny...we all had a first Atomic 4..some of us are still on the first one, some go thru them a little more quickly.

The running rich & idle problems may or may not be related. Get the float/needle working correctly first, and then confirm all idle passages (there are two tiny ones that is intersected by the throttle butterfly) are clear.

Also, make sure you have a good seal at the flange when re-installing.

Welcome.

[lat 64]

Mo'o,

I'm beginning to wonder if you may be missing other safety items. Do you have a flame arrestor?

You said this is your first A-4. ls it your first inboard gasser?
If so, it's time to mention that a good review of fire safety with inboard gas engines should be in your future. Some of these things are not just common sense, I had to learn them.

Russ