I couldn't find a set of risers that had the right angle, height, length and diameter to match up to the Yamaha "Y" pipe that go to the transom. When I bought the Mercruiser manifolds I ordered the entire kit with the risers I thought were closest but after I got them installed they were way off. Not even close.
The Mercruiser risers will work, I've done them several times over the years. The water flow explaination is incorrect but over all a very good conversion.
HT32BSX115 I didn't get to run the boat enough with the 305 to be able to compare it to the 350. The block was busted when I got the boat. I only took it out once and that was only just off the dock. I will say that I need a higher pitch prop. It has a 3 blade 18" stainless on it and it will defiantly launch out of the water with no problem and plane in just a second or so.
Capt Ken Thank you Ken. The risers I got with the kit didn't come close. Do you know the part number of the Mercruiser risers you used? I did explained the water flow incorrectly. For one the water comes up through the bottom of the manifolds and out the top. I knew in my head how it works but I didn't have a script to go by lol
I kind of like the idea of the manifolds matching the temperature of the heads though. Maybe less likely to warp them but I'm no mechanical engineer though.
I kind of like the idea of the manifolds matching the temperature of the heads though. Maybe less likely to warp them but I'm no mechanical engineer though.
I did the same but with full closed cooling. My manifolds have 50/50 coolant flowing through them all the time. Only heat exchanger discharge raw water going to the risers and then out with the exhaust.
