Alternator attitude adjustment

[njlarry]

The alternator on my Universal M25-xpb has a bad attitude and it's eating up the fan belt. I checked it with a straight edge and the alternator pulley is not in line with the other two pulleys. How do I get it aligned as the mounting bolts don't seem to allow for any adjustment?

 

[Rich Stidger]

I have placed washers under the alternator mounting ears to align with the other pulleys. It does take a bit of trial and error, but works.

If this is an OEM original installation, do you know why it is mis-aligned?

 

[Stu Jackson]

Don't know if it's the same for the XPB:

Universal M-25 & M25XP Alternator Bracket Upgrade & Alignment 101 IMPORTANT

http://c34.org/bbs/index.php/topic,7917.0.html

 

[Mark Maulden]

Get a length of 3/8 drill rod and lay across the pulleys in the grooves. It'll tell u real quick if not aligned. Cheap at any hardware store

 

[RichH]

All good suggestions so far.

Another cause of premature belt wear is a sheave that has become 'rough' due to surface rusting. Usually happens to sheaves that are made of pressed steel.
The roughness can be removed by 'dressing' the vee groove surfaces by applying sandpaper onto a 'stick' and holding it to the sheave face while the engine is turning - be damn careful not to get your necktie caught in the rotation parts when doing so.

Prevention - Consider to spray anti-rust compounds, such a 'Boeshield', on the 'bright' vee groove surfaces of the sheaves when preparing for a long term lay-up of the boat.

 

[Bob S]

If the bracket doesn't allow you to add washers you can remove the pulley off the alternator and add a washer there. Been hovering on this site for a while now and lots of engine pictures have been posted. I always remembered RichH's post about rust and it's amazing how many rusty sheaves I've seen.

 

[njlarry]

Actually the pulley is "twisted". That is, the outer edge is about 1/8th inch aft of the inner edge relative to the other two pulleys. The two thru bolts seem to hold this angle and the bracket just adds tension? There is no rust on the pulleys.

 

[centerline]

Actually the pulley is "twisted". That is, the outer edge is about 1/8th inch aft of the inner edge relative to the other two pulleys. The two thru bolts seem to hold this angle and the bracket just adds tension? There is no rust on the pulleys.

im not really sure of what type of alternator and mount you have, but shimming or replacing is your only option....
as for the fore and aft alignment of the v-pullys in relation to one another, it would depend on which direction the engine sets in the boat as to which end i would suggest to place the shims...

but you can figure it out as you are looking at it.
you are going to have to remove the alternator and shim one end of the foot bracket between the engine and the bracket with washers so that it will bring the "twist" out of it.... sometimes it only takes 1 or 2 washers.

BUT... when you remove the alternator you will probably find that either the foot mount on the alternator, the bolts or the engine bracket is worn.... shimming can compensate for this to some degree but the proper fix is to replace or repair the damage.

 

[Maine Sail]

Actually the pulley is "twisted". That is, the outer edge is about 1/8th inch aft of the inner edge relative to the other two pulleys. The two thru bolts seem to hold this angle and the bracket just adds tension? There is no rust on the pulleys.

Make sure you have the proper sized pivot bolt for the alternator ears hole. Universal is famous for using the wrong sized bolts (Yanmar too). They really need to be a snug fit with no slop... If it is "twisted" then this is sign the pivot bolt is too small for the hole in the alt. If the pulley is parallel to the others but just off set either forwards or aft then shims will fix it..

 

[njlarry]

Thank you all so much.
She comes out this week, once I get it winterized will take a closer look. That side of the engine is not very accessible so may have to rely on feel. There is definitely a twist to it and as there is less than 100 hours on the engine (new 2010) the wrong bolts could be the source.