Posted by will (18.104.22.168) on October 10, 2004 at 03:23:48:
In Reply to: A-4 Oil posted by John on 21:30:47 10/07/04:
You have a great advantage being in fresh water. I am putting freshwater cooling in a boat this month that has been in puget sound a year but spent the rest of its life in Idaho. You have a valuable engine, take care of it. I predict that in 5 to 10 years there will not be many saltwater cooled A-4's running. As far as impellers go it depends on how you treat them. We have a Pearson Coaster and the impellers in both pumps had been in them 14 years!! The boat had been in storage that long. I used them a year after. I maintain my engine very well, good hoses etc but I always shut off my thru hulls when I leave the boat. I forgot to open the one for the heat enchanger cooling. No damage done to the engine, it wasn't that long as I always check the exhaust. As a result I changed the impeller. I change them every 2 years now unless they have been abused. I always carry a spare and I am a gear head so it is easy for me to change. The pump under the distributer is usually the hardest to change. Some people pull the two bolts holding the pump and bend the hoses so it is facing up, easier on some installations but it cost you a gasket sometimes. Use hylomar on the gasket and it can be saved, avation permatex won't. I can do it with my eyes closed now. Remove the cover then with needle nosed pliers grab an impeller and pull the shaft out with the impeller. some people do not replace the clip on the end of the shaft, I do because I have the tools but if it drops in the bilge not to worry. The only problem with running an impeller til it quits (besides overheating), is that if a fin breaks off it can plug a hose and restrict water flow. They can be tough to find. Always inspect a removed impeller. I always use 10w30 oil as it is all the same price. I don't think the engine cares. If I lived in your part of the country and used my engine in the winter I would definetly use 10w30. It is thinner in cold weather. The A-4 has a problem with high oil pressure and the drive shaft on the oil pump gear has been know to shear above 50 lbs pressure. If you use 30w keep an eye on the pressure. Be sure it is detergent oil as some 30w is not. I sell impellers also but I would not tell someone to change them every year just so I could sell more.
Will at nuclearengine.com