Exhaust on YSE12

[Royce Hallock]

I sent a post in on replacing the water elbow with a SS version several weeks ago. Well after doing that with threaded 1.5" ells, I am able to get more rpm out of my engine. Before I could only get 2000 rpm with the boat tied in the slip and in gear before black smoke started coming out and 2500 under way likewise. Now I can get 2500 in the slip and a little over 3000 under way. I'm very pleased with the results and my only question is about back pressure. Do I need to be concerned about it? Thanks for the great forum.

 

[Gordon Torresen]

YSE 12 backpressure

The 1.5" pipe that you used is pretty much standard with the YSE12. You should have no problem with back pressure if the run is not too long and the pipes don't coke up. Back pressure is always a concern buth the agony of measuring something in the one PSIG range is usually not worth the effort. Yanmar states that you should not go any smaller than the pipe exiting the engine.