air bubbles coming from lower unit? and a carb question

[storedaddy]

johnson 1979 15hp, when motor is started air bubble come up from the the lower unit in the area of the water pick up and the connection to the upper housing is this a bad seal? the fluid is good not milky. 2--> what is under the small freeze plugs on the carb I am having a problem getting the motor to idle I pulled the carb apart and it was spotless I removed the large freeze plug and it was clean also blew air through all of the passages and it seemed ok so I did not take the other smaller freeze plugs out. could this be the cause of the no idle? start easy throttles up good. should I just try to decarb? get new fuel?

 

[spingley]

Re: air bubbles coming from lower unit? and a carb question

If the gas is old then definately replace it. I am not familier with the smaller 15HP but can you remove all of the jets and be sure the orifices are not partially plugged? And float level check would be good idea, maybe someone will pipe in with something I missed.

 

[bktheking]

Re: air bubbles coming from lower unit? and a carb question

No water in the oil = no bad seals, the bubbles could be coming from the air that gets trapped when submersing the motor, the exhaust housing and lower unit area are somewhat hollow. As far as the carb is concerned if is won't idle, chances are it's dirty. Here's what I do to clean them. Pull the bowl off, remove the float and needle. Remove the seat with a screw driver and the main orifice out of the center of the carb. Removed the idle needle and the top welch plug. You never mentioned replacing the "freeze" or welch plug in your post. Do youself a favour and go buy a carb kit. After soaking the carb for a couple of hours, remove from the bath, wash with water and blow out the passages with compressed air. Put the carb back together same as you dissassembled, welch plugs go convex side out and then can be tapped in place using a 3/8th's extension and a hammer but do not flatten, seal the plug edges with clear nailpolish. Float level should be level with the carb body where the bowl meets the carb surface. Screw idle needle in all the way (do not force) and back it out a turn and a half, this should give you enough to start the motor, fine tune once warm, running and in the lake.

Hope this helps, put a kit in it, you'll see a difference.