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Mercruiser 3 ltr Alternator belt replacement

by Bigplumbs » 17 Jul 2018, 06:37

Hello All

In my Fletcher 19 GTS Sports Cruiser I have the Mercruiser 3 ltr engine and the alternator belt needs replacing and of course the boat is on the water. I have watched several You Tube videos and can see how to do it but in the Fletcher access is not very good.

In some of the videos they show a scissor jack supporting the engine as you need to remove a bracket to get the belt on and off. In one video however this Jack is not shown. Getting a jack in on my boat will be a real pain

So to my question has anyone on here replaced said belt on a Fletcher 19 sports cruiser and if so how did you support your engine

Thanks

Dennis
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by Ianfs » 17 Jul 2018, 10:24

Getting a jack in on my boat will be a real pain


I agree.

I've not done it but I hope this helps in some way.

I watched a marine engineer do this recently at the marina, I wanted to take a video but he said I could watch but would prefer not to be video'd. He told me there are only two ways in which to replace the belt. One is to jack the engine to provide space between the mount and the pulley, which is what you have seen and the other way is to take off or loosen the top pulley in order to squeeze the belt between it, which I think is the recommended version. He said it saves all the faf of jacking the engine and possibly damaging the sump or cracking the hull, although you only need a fraction of movement. There is also a spacer that has to come off, but that looked easy.
He seemed to manage to get the pulley off quite easily, but bet your life if that was me doing it, it would never come off. :D

Another tip, if you manage to change it easily, put on another belt as a spare and tie it up out of the way. Next time just cut the old one off and replace with the one in situ.
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by betty boop » 17 Jul 2018, 13:17

I never did it Dennis but my well thought out plan for Betty was a scaffolding pole across the boat at the engine lifting eye, ratchet strap the engine to pole to hold it up whilst removing the lower bracket and belt. hopefully you see what I'm getting at if not explaining very well.
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by Bigplumbs » 17 Jul 2018, 16:05

Thanks both Ians. I get the ratchet strap and scaffold thing. I am happy to take of the pully instead of jacking up the engine. I kind of thought that the jack was to hold the engine as I will have to remove a bracket as shown in the attached pic at point 2 marked up. If it is just to save taking off the pully I am happy to just remove the pully

Dennis
Attachments
Belt Marked up (Medium).jpg
Belt Marked up (Medium).jpg (183.49 KiB) Viewed 1153 times
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by Ianfs » 18 Jul 2018, 09:48

I kind of thought that the jack was to hold the engine as I will have to remove a bracket as shown in the attached pic at point 2 marked up.


I thought the same. The marine engineer had already removed the spacer No 2 and the engine was still ok, so I don't really know. He said the starboard side fixings would hold the engine steady, which it seemed to.

Best of luck with it, I hope the job goes well. It will certainly make a great how to in the "How to" forum, certainly for anyone else in the future who is giving it a go. :)
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by Bigplumbs » 25 Jul 2018, 17:44

Me and a friend replaced the belts today. What a job some of the nuts and bolts were metric and some were imperial. What fun that was

The old belt was in a terrible state at least worn to half its thickness how it did not break is a miracle

Dennis
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by Ianfs » 29 Jul 2018, 11:58

What a job some of the nuts and bolts were metric and some were imperial. What fun that was


How odd, shouldn't they all be imperial on a US engine?

How did you do it in the end? Sounds like a bit of a pain but was it a case of removing the top pulley?
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by Bigplumbs » 30 Jul 2018, 06:34

The bolts that were metric were the ones holding the alternator on.

Yes we removed the top pulley and in my view it could not have been done without removing that. We found that there was no need at all to support the engine (although we did take the kit) and after removing the lower bracket on the right the engine did not move at all.

The main issue as ever on a boat is the access and the difficulty that this brings together with the pully bolts that took some moving on a thing that rotates. Used a second spanner on opposite bolts and on the last one used the second spanner as a lever on the loose bolts that we undid but left sticking out. Me being too fat also did not help :)

Dennis
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