- Dec 11, 2012
There have been some crankshaft failures in the Casler 45 horse motors. According to a letter put out by Scott the 45 hammers the crank much harder than the smaller halves and of course the 4 cylinder ones(that makes sense). Having recently become aware of the problem, one of my first thoughts was about prop weight. I've run a number of props on my 45 and weighed all of them. I don't have the weights in front of me but they vary widely(particularly as a %) from like 2#12oz or so to nearly 4#. So I'm wondering if the lighter or heavier is "best" in regards to crankshaft failure. I can see it being either way...the heavier prop dampens the hammering of the 45 but puts more load on the crank and the lighter the opposite. I expect there must be some minimum prop weight for a 45 but don't know that anybody knows what it is...my current prop is 2#xoz and it does hit very hard...very little flywheel effect. So what's best to avoid crank failure, heavier or lighter and where is the xover point?