Engine exhaust routing question

[cgrooves]

For starters: Mercruiser 898 (305) engine with a Mercruiser 898 (Gen I) Outdrive. Exhaust goes out the prop hub (closed system?)

Question:
I installed a new prop yesterday and was back at the stern looking over at the outdrive while my wife was driving and noticed some exhaust gas coming out from around the top of the outdrive. I felt the top of the outdrive and it was pretty hot (as to be expected). Is this normal, or should 100% of the exhaust be going out the prop hub?

 

[Don S]

Re: Engine exhaust routing question

The outdrive does get got, just from the gear operation, but it also has an exhaust passage thru it. Yes, the heat is normal. There are also 2 approximatly 1" diameter exhaust reliefs in the lower part of the transom shield. When running most of the exhaust will go thru the prop, but some will still come out of the exhaust reliefs. That may be what you are seeing, that your exhaust bellows has holes in it.