Exhaust under water wher motering above 4.5 knots

[Dennis Lindauer]

Whan motering above 4.5 knots, the exhaust goes under water. It doesn't cause any damage, but I end up with a black soot line across the back of the transom afterwards. I was thinking of switching the exhaust discharge, with the manual bilge pump discharge which is located just above the exhaust, thereby keeping the exhaust above the water level, and no more soot line. Any thoughts from anyone on this and has any body already tried this?

 

[Mike]

check with a qualified mechanic

Dennis:You should check with a good mechanic before you do this. There is something about the need for the exhaust system or some portion of it to be at or below the water line for it to function properly.You didn't say if your boat is diesel or the Zephyr OMC saildrive. This too will make a difference. There is a web site out there for sail drive owners called "saildrive owners.com". It's a good site.Fair Winds,MikeS/B Pitterpat, Lake Huron

 

[Frederick Pierce]

Exhaust Under Water

HI, Dennis I have a 85 oday 28 with a 4.8 Keel I had same problem . When I purched this oday the first owner replaced the 12 hp engine to a 27 hp yanmar 3GM30F which is to much engine for this size 28" so my first sea trial up here on the maine coast my exhaust was under water at 5 ktns with this problem it creats a back pressure to the engine SO my guys it the boat yard which I KNOW and they know there the engines he remended to raise the exhaust outlet up about 5 inches SO, he did inside I had a big loop at the aft section he cut a new hole a 5 inches above the orginal thur hull and fiberglasses up the old one and painted gelcoated you never would know it was done Now I MOTOR 6 knts and my exhaust is above water NOW getting back to your problem what hp you have in your 28 did you always have or this is a new problem. Iknow my engine yanmar other than that I realy don*!t know. Iwould like to know whow you resolved this problem. Frederick Pierce of boothbay maine.used the oday website if you get any anwers. Good Luck .

 

[Charles Cottuli]

Exhaust under water

Hi Dennis,I have a 1983 O'Day 28 and I also noticed my exhaust dipping below the water line with the factory engine installation. The boat seems to sit a bit low at the transom all the time anyway. I never really worried about it since that engine has just about done it's job after 20 years. I like the older O'Day products but there are things the factory could have done better. The engine installation is one of them.I have since replaced the engine with a sweet little 18 HP Yanmar and replaced every thing else but the fuel tank. The exhaust now goes through the transom about 5-6 inches higher and I blocked the old exhaust hole. The boat dips a little more at the transom under power but that's normal because of the added horsepower. Now the exhaust is always above the water. If your engine is OK, I wouldn't do anything but check the condition of the rest of the exhaust system. If it needs replacing then I'd move the exhaust up but I'd take the opportunity to replace the exhaust hoses and add a gooseneck just behind the transom.Good Luck