Oil dripping form air silencer

poolecw

Petty Officer 3rd Class
Joined
Feb 27, 2005
Messages
86
I removed the air silencer cover tonight and noticed a build up of oil at the bottom of the air silencer. There was a decent size puddle of it. Is the common or is the sign of a problem?
 
Last edited:

Swampmouse2

Seaman
Joined
Mar 26, 2014
Messages
52
I too have seen that every time I pull the silencer off my carbs and others. I think it is from unburned fuel hitting the front for the silencer and sitting. My guess the gas evaporates away, and the oil is left. I am certainly no expert, but I haven't had any problems, and like I said, have seen it every time I get down to the gasket. My experience is that it usually is just a drop or two. If the puddle is any size, that may be a sign of some carb issue. Someone will chime in who can speak with authority.
SM
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
most of the time it is from fuel that pours out of the carbs when it is trailered on tilt. I wouldn't worry about it unless you have performance issues. I mean with the engine not personally. (supposed humor).
 

poolecw

Petty Officer 3rd Class
Joined
Feb 27, 2005
Messages
86
most of the time it is from fuel that pours out of the carbs when it is trailered on tilt. I wouldn't worry about it unless you have performance issues. I mean with the engine not personally. (supposed humor).

If this old motor keeps causing me trouble, it could let to performance issues. LOL
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
You didn't say that the motor had any performance issues. It just leaks. Heck, I'm old enough I do that too.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
You did not mention what engine you have. Year/hp? The picture does not show anything. Many engines have a drain system to recirculate this excess fuel/oil back into the bottom cylinder of the engine. Check to see if yours has an airbox drain hose which will connect to a hose barb at the bottom front of the engine block. If your engine has one, is it plugged?
 

poolecw

Petty Officer 3rd Class
Joined
Feb 27, 2005
Messages
86
The engine is a 1984 Johnson V6 150hp. I've got a discussion on its performance issues going on another thread. There is a hose coming from the base of the air silencer. I assume that is what you are referring to. I'm at work not and can remember where that hose went to.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
That is the airbox drain hose. It should be connected to a small hose barb in the block under the bottom carb. It's job is to evacuate any excess oil/fuel and ingest it into the bottom cyl. This is usually done at start up and if there is much accumulation in the airbox when started, you may see a little excessive smoking for 30 seconds or so till this excess gets burned off in cyl 6. Some of the 70's carbs tended to weep more fuel from the carbs when the engine was tilted up. Later carbs like yours were less a problem.
 
Top