The napa store in my location who sells boat prts tells me that SIERRA pt.#18-2346 and PRT # 18-3114 are no longer avail not even from the manufactor. Now I find that hard to believe since the alpha 1 mr is still widly used on a lot of older boats. Wht I need from you fine ppl is tell me where I can find this parts. I just recently replaced all the seals and O rings in my unit and had to drill the old retainer nut out. These parts are the retainer nut for the upper bearing and race under the water pump and the insert cup for the water pump impellar. These two parts are holding me up from finishing my conquest and adventure. PLs help me here folks, as you always do. tkks in advance tboss-----terry