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Old 09-28-2012, 01:05 PM   #11
Forkliftt
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City: Biloxi Mississippi
Country: USA
Vessel Name: Patricia Louise II
Vessel Model: 1983 42' Present Sundeck
Join Date: Oct 2007
Posts: 2,444
Wear items

HC, I always try to think of mechanical components as an assembly of "wear items". For instance, a lot of starters have bushings that the armature and starter drive spin inside of. If your engine starts frequently, say like a UPS truck, then those bushings will surely not last as long as the same starter in a boat application that starts and then runs for possibly several hours. BUT, if your batteries are low or you have a voltage drop in your positive or negative cables on your boat, then you will see increased amperage draw from your starter (Ohm's Law). These higher amps will probably cause burned tips inside your starter solenoid, possible arcing at the brushes and the heat can actually damage the field coils and allow them to short against the starter case. Pisser. Probably not the case usually but possible. So there are many causes of parts failures. You had a failure on your tensioner that caused a belt failure. I think tensioners are a great advancement. One of my pet peaves is to follow up behind another mechanic that has tightened a V belt WAY too tight. He solved the problem. Squealing alternator belt (only right after start up, thats when the big load occurs), his solution is to tighten that SOB as tight as possible. Problem is- two months down the road the alternator bearings fail. Why? Excessive belt load. Usually the original problem is a very worn alternator pulley. By the time a new belt has slipped and worn to match the profile of the old pulley, the belt is glazed and no longer is soft enough to not slip on the pulley. I personally think that once a boat gets to be the age that ours are, any failure needs to be really understood- and look at that part or component as a piece of a "system". Understand the system and you will probably understand the failure. ...Personally, I keep spare coolant lines, trans oil cooler and an engine oil cooler as spares on the boat along with a spare RW impeller. I yield the floor!
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