Mystery part - Transfer Port Drain?

[dajohnson53]

This is the 1974 Merc 110 (9.8) that I've gotten a lot of advice on. I'm not a mechanic and appreciate the help on what are probably easy jobs, but new to me. <br /><br />There's an external part on the engine that my OEM shop manual doesn't even show, and the Seloc manual shows, but does not explain.<br /><br />on the starboard side of the engine is what I believe is the "transfer port cover". Near the upper rear corner of that is a 90 degree fitting coming out, connected to a small diameter tube. The tube runs to a similar fitting near the forward, lower corner of what I think is called the crankcase cover - the part which the carburetor attaches to. Like I said, the OEM manual doesn't even show this tube, and the Seloc manual calls it "drain hose" in one of the photos - but doesn't explain it at all.<br /><br />It seems like this is cracked near the rear fitting and bubbles and/or gurgles a little fuel and/or air. It's obvious that it would be easy to replace the tubing with similar, fuel-capable tubing which is what I will do. <br /><br />But what is this for?<br /><br />Thanks for any insight you can give.

 

[WillyBWright]

Re: Mystery part - Transfer Port Drain?

That sounds like a bleed line. It takes oil-rich unburned fuel that puddles in the crankcase and diverts it to a crankshaft bearing. It's not there so much for lubrication as it is for cleaner running. Otherwise that stuff just dumps out into the water.

 

[dajohnson53]

Re: Mystery part - Transfer Port Drain?

Thanks. That makes sense. Last time I ran it it looked like it was oozing a little messy crap, and I was planning to replace it just for that reason.