Exhaust system in Irwin 37

[stevee9259]

I'm replacing the exhaust system in my Irwin 37 and am considering increasing the diameter. The engine is a Perkins 4-108 diesel. The original exhaust uses a 1.5" diameter NPT thread out of the flange, then the rest of the hot section is also 1.5" galvanized out through the riser, then the hose for the wet section is 2" diameter. The old water lift muffler is 2" in/out from the top. The muffler and the old riser are in poor condition and the engine has been over heating at anything greater than 2,300 RPM's. My plan was to replumb the hot section with 2" galvanized and then use 2" hose and a new Vernalift with 2" in/out. The problem is that Centek recommends a water lift muffle with 3" in/out for a 50 hp engine. So that is my question: should I change out the entire exhaust with 3" diameter or should I just stick with the original design as planned with the exception of the increased from 1.5" to 2" diameter for the hot section? Any advice would be appreciated. Thanks, -Steve

 

[letterman]

I doubt its your exhaust that is causing the overheating. I have the original system set up -with new pipes. Look for your overheating problem someplace else.
I'd stay with the original system, but have it made from stainless. I am not sure but galvanized may give off fumes when hot. I went with regular blackpipe, which you can buy anywhere.