Changing the Alternator Belt on 3.0L mercruiser

This is a continuation of this thread:

http://forums.iboats.com/showthread.php?t=48596

"My belt broke on Memorial Day. Battery went dead within 100 yards of dock, 45 minutes short of sundown. I was quite lucky, this time. Anyway, I just finished changing the belt on my 3.0 mercruiser. I used screw type jack from my truck. 1) Placed under engine beside alternator mount 2) Turned gently by hand until engine moved up slightly, 3) Removed bolts 4) Installed 2 belts, one for backup 5) Reinstalled bolts 6) Removed jack 7) Cable tied spare belt around spacer. Thanks everyone for the information. I love this resource Belt is 3/8" X 40"


I tried this today and it worked PERFECTLY!! Could not be easier to swap those belts.. You can even jack the motor up a little to get the belt from out around the front pully/motor mount.. then drop it back down after install and those bracket bolts go in like butter. This seriously could not have been easier.

Once again, a basic scissor jack from almost any car will work. Play with the placement.. I put mine from the back instead of the front since my boat was a little different. Get it square underneath the bottom of the alternator bracket, and you are golden. This was seriously so easy this way.. Whole job done in under 10 minutes.

Re: Changing the Alternator Belt on 3.0L mercruiser

There is an easier way. Just remove the 2 bolts on the port side of the motor mount. Remove the spacer, replace the belt, put the spacer and bolts back in and you are done. No jacks of any kind requiered.
One thing to remember doing it your way. If the mount is not reset exactly as it came out, or something get's under it, your engine will be out of alignment and the next step is coupler failure. UNLESS you pull your outdrive and check the alignment. ............. Did you?

Re: Changing the Alternator Belt on 3.0L mercruiser

I too did mine without a jack. It is a big cumbersome to get the belt out, but it will come out.

Re: Changing the Alternator Belt on 3.0L mercruiser

Yeah, I'm just removing the bracket.. not the mount. I've tried in the past to do it without the jack, and the motor slumps just enough to not be able to start the bolts again. Also a pain trying to squeeze the belt between the front pulley and the motor mount..

Re: Changing the Alternator Belt on 3.0L mercruiser

Maybe my wording wasn't clear. That's why I included the photo. I did NOT remove the motor mount, ONLY the spacer. The two bolts only remove the spacer. The engine drops just enough to make installing the bolts difficult. So the jack only supports the weight enough to make the bolt hole alignment easy. Sorry I wasn't more clear.

Re: Changing the Alternator Belt on 3.0L mercruiser

Don S said:

There is an easier way. Just remove the 2 bolts on the port side of the motor mount. Remove the spacer, replace the belt, put the spacer and bolts back in and you are done. No jacks of any kind requiered.
One thing to remember doing it your way. If the mount is not reset exactly as it came out, or something get's under it, your engine will be out of alignment and the next step is coupler failure. UNLESS you pull your outdrive and check the alignment. ............. Did you?

Click to expand...

Holy crap, thank you for posting this thumbnail !!!!!!!!!

Re: Changing the Alternator Belt on 3.0L mercruiser

Hi, Does this work on a OMC 3.0 liter ?

Re: Changing the Alternator Belt on 3.0L mercruiser

Just a quick question on this subject, with your 3.0, do you have a 3-groove pulley or a single groove?
Mine has the power steering option, so my main pulley is a 3-groove. Talk about a chore, you have to take the pulley off as well as the spacer, as there is not enough room to slide the belt between the motor mount and the pulley.

Re: Changing the Alternator Belt on 3.0L mercruiser

waye45 said:

Hi, Does this work on a OMC 3.0 liter ?

Click to expand...

Most likely...what year?

Re: Changing the Alternator Belt on 3.0L mercruiser

Tried this last week, and it worked great.

I removed the spacer with the jack just under to support the alignment of the spacer bolts when put back in. Whole job with the right belt - 15 minutes

I had a little trouble getting the right belt as it is not easy to find using the cellphone at the parts store searching the web. The service manual is not kind enough to give you the specs, but the alternator on mine was adjustable so it worked out well.

Re: Changing the Alternator Belt on 3.0L mercruiser

First time poster, this worked perfectly. I saw my alternator belt was really worn and I was worried about changing it, thanks!