Leave Well Enough Alone?

Ron20324 · Jun 27, 2016

Replace it NOW and save the others as emergency. AAA does not have boats.

Rich Stidger · Jun 27, 2016

600 hours is not a lot. If the belt looks good, I would be sure I had the proper spare and leave the belt as is. Now if you saw wear or had more hours, then I would feel differently. But there is certainly no down side to replacing it now and keeping the original as an emergency spare.

Charlie Jones s/v Tehani · Jun 27, 2016

Replace it and keep the old as a spare. Then you KNOW it fits. If the new one has a problem, best find it out BEFORE you go

njlarry · Jun 27, 2016

TSBB 2 said:
Replace it and keep the old as a spare. Then you KNOW it fits. If the new one has a problem, best find it out BEFORE you go

Totally agree. When you get the new one compare the top edges to the old for any signs of wear.
Your old one may be fine but why worry about the spare fitting unless you are sure it is the correct one.

Terry Cox · Jun 27, 2016

Ditto Rich's suggestion. If it had signs of cracking or excessive wear, then yes replace. We have well over 600 hours on our 4JH2-TE belt and is still in good condition since taking possession in 2002. I check it periodically and tighten as necessary. I have a spare.

centerline · Jun 28, 2016

as with EVERYTHING else on the boat, keep it inspected regularly, and replace it when needed.... when the conditions are nearly perfect, things can last significantly longer than an identical part being used in severe conditions....
in the case of your alt belt, its obvious the pulleys are in line and the alt hasnt been pulling hard, and so there is very little wear and dust.... this is good... and when the conditions are right, take advantage of the savings by running the belt until you see signs of stress or wear in it...
the key to it is frequent inspections and knowing what you are seeing when doing the inspecting...

there are somethings that cant be inspected as easily, and yet are a consumable wear item, so then a regular replacement schedule should be used...

and in my opinion, it is good to carry spares, but my practice isnt to carry the used parts as spares, but to keep them in service and running to maximize their life and my dollar.
I carry new parts for spares, so that when I need to replace it, I will be doing it with NEW parts so that I can maximize the life out of it before needing to work on it again....

for me it doesnt make sense to be running a new belt, with the used one as back up, waiting for the new belt to shred so that I can install the used one, so that I might be able to make it back to the dock so I can go get a new belt, and then come back and work on it again changing to the new belt so that I can save the old one for a back up....

I change out an old belt with a new one that I have been carrying as a spare, and buy a new one as my back up....

impellers are the same way... if it isnt good enough to run, it darn sure isnt going to be taking up space in my inventory of spare parts... and if it is good enough to run, why was it removed??

there are those times when its convenient to replace a part that is very little worn, but is hard to get to, because you have it apart for some other reason.... but I will still discard the take-off part for a new one to carry as my spare...
my boat is not a world traveler at this time, and I keep it in good working order and in such a condition that I dont feel carrying "used" consumable parts as my redundent spares is necessary or desired to maintain a safe, dependable, and self sufficient maintenance regime and boating lifestyle....

Scott T-Bird · Jun 28, 2016

I agree. In the past, I've kept old parts as spares. I've never actually USED an old spare part, though. They all eventually end up in the trash. It is a much better practice to have a spare NEW part.

Kings Gambit · Jun 28, 2016

Marc14857 said:
The alternator belt on my Yanmar 4JH4AE is going on its 8th season ~600 hours. The belt looks virtually new with no signs of black dust, cracking etc. It is a single V belt driving a Balmar 100 Amp alternator with a belt management system. We are leaving on a two week cruise and I am trying to decide whether to replace it as a preventive maintenance task and perhaps have a problem with the new belt or "leave well enough alone".

Thoughts?

Kind of a coincidental post here; I just bought a new replacement for the belt on my Yanmar 3JH3E that has seen over 1700 hr of service and that I will install b/f my next trip over the holiday weekend. A whopping $22!! Don't sweat it; replace it and have a good trip! Keep a new spare.

Maine Sail · Jun 28, 2016

I had a customer go up on a ledge by maximizing the old part life beyond where he should have.. In the end it cost him a boat-load more money, like 10,000% more money, than if he'd just changed the filter before it clogged. On many a small diesel engine a broken belt can leave you without an engine due to the belt also driving either raw water cooling or the freshwater side..

While this may sounds like a good plan on paper, pushing the belt even longer, I can't even begin to tell you how many times an owner has said; "Here, use my on-board spare parts." only to find out they don't actually fit.

I have an impeller sitting on my desk as I type, stored on-board as the spare, which is the incorrect part. It was the only spare impeller on-board the boat and the owner asked me to install it while I was out there replacing the start switch... Gasket was wrong too. He's now paid for two trips to the vessel because his on-board spares were incorrect.. Somewhere along the way the pump had been changed yet the parts he purchased were still the "original" part numbers. Belts are one of the the most often incorrectly sized spares I see but I've also seen incorrect filters, solenoids, and other on-board spares.

Please double check that your spares actually fit your engine and consider changing them well before you really need them and they decide not to work.....

Stu Jackson · Jun 28, 2016

Maine Sail said:
only to find out they don't actually fit.

I have been through a few different alternators and with my M25 the new fangled bracket (circa 1999!!!).

It is IMPERATIVE that once you find out what belt you use you blinkin' write it down.

It is incredible to me that so many skippers have NO CLUE as to what is the "right" belt for their particular installations.

On our C34s with M25 and M25XP engines, various skippers have reported using different belts, over the course of the past 25+++ years.

Of course, that's reality. One size does NOT fit all.

I use a 3/8" 7395 belt. Used to use a 7400. Some skippers use a 7390. Go figger...

Then, when you find what you need, go buy two or three of them at a time and clearly label them.

And throw out the old ones you've been hoarding that don't fit!

And throw out the old ones you've been keeping as "backups."

Change the belt before you go on a cruise, 'cuz when you're on a cruise the very last thing you want to be doing is "work." Do the preventative maintenance before you go.

Throw out the old one and have new ones as spares.

kimelmore · Jun 28, 2016

On my old boat I kept my "new" spare belt inside the engine compartment and used an old winch handle holder to keep the required tools to change it so they were handy. This was after the original belt shredded itself in the middle of the main ship channel with a tanker bearing down on my position. I scrambled for the belt (at least I had bought a spare) and the wrench etc and got the belt changed before the tanker started sounding the horn to tell me to get out of the way or pay the penalty. It is what I like to call a "single point of failure" item. If the belt goes you don't just lose your alternator you lose your fresh water cooling too. My first clue of something wrong was my overheat buzzer going off. As to whether or not to keep old impellers and belts for spares... they always end up in the trash anyway. If I was doing extended cruising I might think otherwise but that's my take on it.

centerline · Jun 29, 2016

Maine Sail said:
I had a customer go up on a ledge by maximizing the old part life beyond where he should have.. In the end it cost him a boat-load more money, like 10,000% more money, than if he'd just changed the filter before it clogged. On many a small diesel engine a broken belt can leave you without an engine due to the belt also driving either raw water cooling or the freshwater side..

While this may sounds like a good plan on paper, pushing the belt even longer, I can't even begin to tell you how many times an owner has said; "Here, use my on-board spare parts." only to find out they don't actually fit.

I have an impeller sitting on my desk as I type, stored on-board as the spare, which is the incorrect part. It was the only spare impeller on-board the boat and the owner asked me to install it while I was out there replacing the start switch... Gasket was wrong too. He's now paid for two trips to the vessel because his on-board spares were incorrect.. Somewhere along the way the pump had been changed yet the parts he purchased were still the "original" part numbers. Belts are one of the the most often incorrectly sized spares I see but I've also seen incorrect filters, solenoids, and other on-board spares.

Please double check that your spares actually fit your engine and consider changing them well before you really need them and they decide not to work.....

I strongly agree that one should be absolutely certain they are carrying the correct parts to fit their application, and I also agree that the consumable wear items be replaced as soon as there is any signs of wear. some of us know when that is, and others dont...
and I will also agree if one doesnt know what they are seeing when they are inspecting, maybe its better to just replace the part and remove all doubt (fuel filters and impellers), but I still recommend carrying new parts for the spares, but then if one isnt sure that the new part will fit, then I suppose they should carry the old used parts to install when the new one breaks/fails.
it makes no sense to carry parts that dont fit, and it makes less sense to install an old part if you have a new one that does fit.... it does make sense to know what you carry as spares, and to discard the worn out parts when they are taken out of service.

for those of us that know when a part needs replacing, we dont ponder over when or if it should be done, we just do it to maintain reliability in the system.. others who dont know, sometimes ignore the inspections ("out of site-out of mind", or "ignorance is bliss", or "there's nothing wrong, it runs great") and then have a sudden failure, and then claim they "just looked at it just the other day and it was working fine".....

routine, timely and thorough inspections and a preventative maintenance program is only as good as the knowledge and care of the person doing the work... and that is where the savings and security will come from if one is trying to create a safe, dependable and self sufficient boat.

Franklin · Jun 29, 2016

I would say that you should get 2,000 hours out of your original belt if the alternator is original but it doesn't sound like it is, so I would say this belt should last 1,500 hours. AKA...don't sweat it, especially if you haven't noticed any wear. If a belt broke now, it would be because it is defective but considering it has lasted this long I'd say it isn't defective. The new belt though you don't have a clue as whether it is defective or not. In other-words, from an ex diesel mechanic, don't mess with it now. Find something else to worry about like your filters or your rigging or your steering gear or your fuel tank and fuel.

I'm on a 10 year old engine with 1,200 hours on it in the middle of the south pacific and about to take a 1,300 mile leg to Tonga and it is looking like I will need to motor the first day and maybe the last two days of the trip to fit the weather window and I'm not sweating the original belts.

CloudDiver · Jun 29, 2016

These 'link belts' are adjustable in size and great to carry as an emergency spare. I use one on my drill press drive pulley, works perfectly. I've never installed one a boat's diesel, but I have put one on a tractor and its still running with that belt.
Not everything from Harbor Freight is total crap, these link belts are exactly the same as those sold by woodworking specialty shops for twice or three times the price, made in the same factory (in China). Check the Rockler Woodworking website or Grainger and I'm sure you'll see;
http://www.harborfreight.com/vibration-free-link-belt-43771.html

Mark Maulden · Jun 29, 2016

My installation is one belt drives all. I had a situation where the alternator mounting bolt broke. Fortunately, it was just outside the marina and fortunately, the belt did not jump and i made it back into the slip dead slow. I now also carry belts that fit minus the alternator so the fresh water pump can turn in case of an alternator problem.

All U Get · Jun 29, 2016

Scott T-Bird said:
I agree. In the past, I've kept old parts as spares. I've never actually USED an old spare part, though. They all eventually end up in the trash. It is a much better practice to have a spare NEW part.

I agree with Scott. If you were changing it for a good/any reason, your instincts were right, toss it.

All U Get