Posted by John (220.127.116.11) on March 22, 2004 at 22:25:20:
In Reply to: Atomic 4 vs Stevedore posted by Brad Houck on 19:48:39 03/22/04:
Apparently the Stevedore model was just an A-4 with the inlet restricted to limit the power to comply with Canadian restrictions. Since the air flow is dependent on speed the restrictor only has an effect at high speeds. From what I have read this effect only occurs above about 2000 RPM and therefore makes no difference for most auxiliary sailboats which typically are fitted with props for about that speed. If you are being limited by air flow, you could remove the restrictor and have a standard A-4. It won't do any harm. If it has no effect than you need to go to a smaller prop if you really want to run at a higher engine speed. It is not clear why you want to run higher RPM's, you don't mention any problem with boat speed and fuel consumptions may be better where you are now. If you are at or near hull speed now you wont get much benefit by higher speed or more power.