Most sailboats these days have ‘power using systems’ aboard like, a pressure water pump, a fridge and radar. Then too most of us have an alternator that provides reliable, trouble free service as long as they are maintained and replace when worn out. Sadly this area of maintenance is often ignored by cruisers until there is a failure.
Generally that failure is caused by a worn or broken belt. Once that happens the system it drives comes to a quick stop, many times just when we need it most. You may not even be aware at first that there’s a problem until the loss of water to cool the engine causes the temperature gauge to climb into the red zone and your alarm sounds, you do have an alarm, right?
Generally the belts used to power our accessories are of the ‘V’ type but you may find yours to be a flat ribbon type. It’s not uncommon for one belt to do more than one job like sending power to the alternator and a pump. You might find you have only one belt doing the job and your buddy might have two doing the same job, just depends on the engine. However, you have to look each year at those belts for wear and tear. This is a great winter job.
So your first step is to inspect the engines belts. Aside from the obvious cracks that scream ‘replace me’, you also need to check the belts for tension. So, how tight should the engine’s belts be? Well, without a tool to measure with the answer is going to be subjective. However, a good guide is to adjust the belts so they don’t slip but not beyond that point. So….tighter isn’t better.
If you’ve a belt that’s slipping (humm…what’s that whining sound?) it’s not going to charge or turn the power accessory like it’s supposed to. It’s also likely to wear out sooner and/or break long before it should. If it’s too tight, it’s going to hurry up the wear on seals and bearings.
So, how do you know if the belt is slipping? Look for belt dust on the front of the engine or the alternator casing and fan. This stuff is so fine it often feels like oil. Does it look smooth and shiny? That too can mean it’s slipping. If it looks smooth and shiny then you should probably replace it.
When you’re going to tension the belt for the alternator, fridge, water pump, etc. then you’ll need to use that old high tech stand-by…a hammer’s handle. You use it to lever away from the crankshaft pulley and then tighten the holding/fixing bolt that holds it in place. Be sure each belt matches the pulleys it turns. They should be even with or just slightly above (like just a hair above) the top of the pulley sides.
Belts are cheap and easy to do and can make the difference between a fun cruise and a frustrating one. You should think about replacing them every couple of years or 375-400 hours of use…which ever is first. Don’t forget, a new belt may need to be adjusted and re-tensioned a few times during first 75-100 hours, so be sure to keep your eagle eye on them.
Keeping our power systems working well on our sailboat isn’t hard. It’s just one of those gotta do maintenance items. Unless of course you like being towed back to the dock. So check the belts on your sailboat marine engine today!
1 Comment posted on "Sailboat Power Systems"
Charging your DC systems on December 20th, 2008 at 12:51 pm #
[…] One of the more common problems is with an improperly adjusted alternator drive belt. If the belt’s too loose the alternator won’t turn fast enough to reach its maximum charging output. If you want to see about how to adjust your belts, you’ll find more information about it here. […]
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