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Arie S
08-15-2009, 08:14 PM
We have 2 mercruisers apart my sons 260 and my 86 205/4.3. the risers are mercruiser but one has a stainless insert in the exhaust outlet of the riser. Looking at mercs parts listings for those engines it shows a tube water seperation. 3 of the risers are missing them and 1 has it I think if thats what it is. Do I need them ????? thanks John

MOP
08-17-2009, 01:20 PM
We have 2 mercruisers apart my sons 260 and my 86 205/4.3. the risers are mercruiser but one has a stainless insert in the exhaust outlet of the riser. Looking at mercs parts listings for those engines it shows a tube water seperation. 3 of the risers are missing them and 1 has it I think if thats what it is. Do I need them ????? thanks John

Usually they only come out when the risers have corroded some, I have had to fish them out of the Y pipe. They will choke off the exhaust lodged down there! If they show of much corrosion you may want to look into replacing the risers, I would check both Barr and Osco one of them should have direct replacements cheaper then the Merc part.

Phil

Arie S
08-21-2009, 09:42 PM
what is their function? to keep the water from going back down the engine when it is turned off. I checked my brothers 87 Wellcraft with a 350 no water seperation tubes and he has no issues with his boat. So are these tubes needed or should we get 2 sets of risers. Thanks for any help. I'm just confused :confused: John

MOP
08-22-2009, 07:02 AM
The length has more to do with sucking water vapors back into the engine between exhaust pulses at idle speeds, too short and you get reversion. Whether or not not that plays out in your case who knows, being as you have bone stock engines you I am guessing will be Ok.

Arie S
08-22-2009, 10:45 AM
Ok we'll keep the old risers for now, and keep our eyes open for some newer 4 inch replacements with the cast in seperators. I think thats the way to go. Thanks for your help