I am planning on changing my alternator pulley to an aftermarket billet style.

My question is what's the best way to keep the pulley from turning when removing the securing nut? Can you like, jam a wood block between the pulley and belt to prevent it from turning. This seems like it could stretch the belt or maybe even bend the shaft. How best to get that pullyy off / on while the alternator is still mounted in the boat?

Thanks!

Impact wrench.

yea I know - trouble is I don't have one... What's the next best way?

I don't know. I tried to install a billet pulley on my Mustang alternator. I got the old one off without an impact and a new billet one back on. I couldn't get it tight enough without an impact and it got loose and ruined it.

What he said, it takes a tool to remove and replace the pully and not damage it.

Yup impact is only way I think you can get it tight enough w/o damaging it. Look at it as excuse to buy small compressor and impact wrench, you will never regret it.

Short-cuts lead to bobbing up and down out in the water with a boat that won't run or start.

Just trashed my merc blue alternator trying to remove the pulley!!! Older merc instruction book showed clamping the pulley into a vise using an old belt to cushion the pulley. In a rush, I trashed both the pulley and the alternator casing. If you've ever priced one of the blue alternators as a repair part, you will know that it is cheaper to buy a new engine, remove the alternator and throw the engine away. The newer alternators are not considered servicable, so no instructions are given to remove the pulley.

Just take it to a local alternaor shop, they can do it with a impact in about 2.5 sec. It will not come loose if installed by someone who has done it many times

Steve

Oh yeah, I own a shop that rebuilds about five hundred alternators and starters a month