Mercruiser 3.0L Alternator belt replacement.

[annageek]

So, along with the gear shift issue, the alternator belt is on its last legs, as it's getting super dusty when running (despite being tensioned correctly), which I understand is a sign that it is slowly but surely eating itself to pieces. I know it's at least 3 years old, and according to the boat's service history, it could be as old as 10 years... so probably wants replaced asap as a preventative measure. I was actually going to replace it in the winter, so I have the correct sized belt already. The problem that I encountered (which stopped me from doing the job this winter) is that I simply cannot get the old belt off/new belt on.

I get the bit about supporting the engine and removing the engine mount spacer block that passes through the loop of the belt. No problems here.

It's the idler/block circulation pump's pulley (see the picture below) that gets in the way. I have about 2-3mm of space between the lip of the pulley and the top of the main engine mount's stud (the bit you use for height adjusting the forward end of the engine). I need to get that pulley off the block circulation pump so I can change the belt but can't!

I've read it should just be a close fit, so should come off as soon as you remove the 4 bolts, but it will not come off! It must be rusted on I guess? Questions:

1. Am I wrong about it being rusted on, and is it on a taper of some kind instead?

2. Is the round lump in the centre of the pulley a spigot over which a hole in the pulley sits? Or is it part of the pulley? (I can't tell, because some helpful person has spray painted it for some reason!!!!!)

3. If the pulley's lump is a spigot, can I use a puller of some description to force it off? What is the best type of puller to use so as not to mess up the pulley itself?

4. Am I missing something?


Ugh... another job that should take 10 minutes that's actually going to take hours!!!! Ahh the joys of boating

As usual.. thanks in advance!!

[betty boop]

no expert but ur missing the pic so can't see if its the 3.0l same as mine

[annageek]

Oops... just testing

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Thanks!!

[annageek]

I really am an idiot... should have also confirmed, yes, it is the 3.0 Mercruiser. The only difference I think is that the forward-most engine mount may be a custom one for the boat - hence why this problem seems pretty unique.

[Ianfs]

Will this help Anna?

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[Ianfs]

Although reading your post again, I think this may be your problem, the gap is too tight to remove the belt easily? Is that right? This pulley is a very close fit and they are normally on a tapered surface, consequently it will be difficult to take it off regardless of whether it's rusted or not. I'm assuming you have loosened the alternator in order to make the belt loose so that you might be able to jiggle it out?

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[annageek]

Will this help Anna?

The attachment image_91814.jpg is no longer available

Unfortunately no. That's the bit I understand (even if it did take a while to actually believe you have to remove a major part of the engine's structure to replace an alternator belt - crazy!)

The problem is, without that block there, there is still a pinch point between the pulley and the stud that comes out the top of the engine mount (circled green below). I have read other people saying it's a close fit and they have to sort of 'spudge' the belt through the gap, and to that end, I even bought a cogged vee belt, thinking that it'd have a bit more 'spudgability' to get through the gap, but even still, it's not even close. Like I say, I reckon the gap is 2-3mm and I would say I need a minimum of about 8mm to even stand a chance of swapping the belts. If I can get the pulley off the block circulation pump that it's directly mounted to, then that'll be fine (even if it is more of a faff than it should be).

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[annageek]

Yes, your second post is right.

Yes, I have loosened the alternator so the belt is loose, and tried to pull the belt through the gap, but it's not going to go. I think even if I could get it off this way, it'd damage the belt in doing so, thus making the replacement in need of a replacement before it's even fully fitted back on the engine.

[Ianfs]

I've done a bit of Googling and found that this is not uncommon, so its not down to a special fletcher front mount position.

I'm now gobsmacked that Mercruiser have made this the way it is......dohhh!! Most of the bits on the 3.0l are rally easy to reach compared to the V6/V8, so this is really stupid.

I've also made a few calculations, should the pulley not come off. If you were to mark the front mounting bolt so you can return it to its original position then lift the front of the engine by say 5mm, the stress on the Gimbal Bearing would be no more than a slight movement of say .1 mm , which should be insignificant.

I hope this is useful?

[annageek]

I've done a bit of Googling and found that this is not uncommon, so its not down to a special fletcher front mount position.

I'm now gobsmacked that Mercruiser have made this the way it is......dohhh!! Most of the bits on the 3.0l are rally easy to reach compared to the V6/V8, so this is really stupid.

I've also made a few calculations, should the pulley not come off. If you were to mark the front mounting bolt so you can return it to its original position then lift the front of the engine by say 5mm, the stress on the Gimbal Bearing would be no more than a slight movement of say .1 mm , which should be insignificant.

I hope this is useful?

Yup... and it's not like it's the sort of item that might just break and potentially leave you stranded if it's not easily replaceable... oh wait.. I must admit, I struggled to find others with the same problem on google... everyone just seemed to be confused by the spacer block that needs removing. I think I'm definitely going to fit a spare belt already behind all the pinch points and cable tie it out the way - as many online suggest!!

My main issue is that knowing the pulley is stuck on, then I WILL need to get it off for some reason in the future, and will just have to struggle later down the line. Having a look at the pump onto which the pulley attaches (http://cdn.shopify.com/s/files/1/0748/6631/products/IMG_8141_1024x1024.JPG?v=1426032913 then it does appear to have a spigot with a radiused edge in the centre - exactly the same as the lump in the centre of the pulley I was talking about in the OP. Therefore, it stands to reason that this is indeed a spigot that I can use to push against with a suitable set of pullers to draw the pulley off whatever it is holding it in place.

Otherwise, if I do go for the lifting the front of the engine option, I have to devise a method of doing this. Due to the weird shape of the bilge, I can't get a jack under anything substantial to nudge it up. Therefore I will have to lift it from above. I am thinking a chunky beam of timber (fence post?) across the engine, supported on the coaming at each end.Then, with my car's jack atop the beam of wood, I can create a loop of decent rope through the engine's lifting eye and over the top of the jack. In theory, I can imagine it working... but I am an engineer and understand that 'in theory' and 'in practice' are in no way related!