Alternator Install on a Merc 3.0L - Maxum Boat Owners Club

deanries · 08-12-2015, 12:39 AM

All -

The bushing that installs on the mounting bolt that attaches to the engine bracket (boats.net, Item 20 - part number 63894) for my 1992 Maxum 1800SR is considered obsolete. Mine is worn and needs replacement so I need a location that still has a few to sell. They call the item a spacer but it is actually a clamp up bushing with a 3/8" ID and a 0.625" OD, length if 1.125" and made of steel (cad plated not necessary). Waiting for suggestions!
Dean Ries (Go Big or Go Home)

mmwjr · 08-12-2015, 03:43 AM

Not sure where to find one but I would think a machine shop could make it.

shrew · 08-12-2015, 04:31 PM

It's not like this needs to be ignition protected. Can it be sought outside of the marine industry? (Automotive?)

mmwjr · 08-13-2015, 12:50 AM

Just googled it and had several hits eBay,....

Under $2 US

deanries · 08-16-2015, 04:03 AM

All -

This is what I have found out. Later installations of this alternator have went with a shorter bolt and pick up the fwd lug of the mounting bracket. Since there is quite a bit of vibration (broke off bolts in the block, cracked adjust brace, etc.) don't know why they would do that but Oh well. Part of my job as an aircraft mechanic has led me to a machinist who is fabricated a bushing for me. Thanks for the replies, most appreciated.

Dean Ries (Go Big or Go Home)

mmwjr · 08-16-2015, 04:43 AM

Quote:

Originally Posted by deanries

All -

This is what I have found out. Later installations of this alternator have went with a shorter bolt and pick up the fwd lug of the mounting bracket. Since there is quite a bit of vibration (broke off bolts in the block, cracked adjust brace, etc.) don't know why they would do that but Oh well. Part of my job as an aircraft mechanic has led me to a machinist who is fabricated a bushing for me. Thanks for the replies, most appreciated.

Dean Ries (Go Big or Go Home)

Post some pictures before and after the repair so others with this set up can learn, thanks

deanries · 08-19-2015, 01:26 AM

Mike & others,

Once I have some photos I will post them. Right now I am waiting for the machinist to fabricate the bushing for me. Hopefully that will happen this week so maybe over the weekend I'll take the photos. Can't believe they would change the installation because vibration is an issue with the 3.0L Mercruiser and how the alternator is installed (blame GM). Thanks for your reply Mike and the suggestion.
Dean Ries (Go Big or Go Home)

deanries · 09-13-2015, 01:14 AM

All-
Finally had some time to replace the worn out clamp-up bushing on the alternator install on my 3.0L Mercruiser. The F-type bracket that mounts to the block uses this bushing to help stabilize the alternator from vibration which seems to be a problem with the design (GM Mfr). Since I work at Boeing I was able to have a machinist machine a bushing meeting the dimensions that were needed. I will try to include the pictures I took in the process of replacing the bushing. Also, the belt tightening brace cracked numerous times due to the vibration. What I did to alleviate that was to take a 5/16" fender washer and cut the upper and lower sides to match the brace. That did the trick for me and I have a picture of that washer which I will try to post, For those with later models, 1995 and after I think they have removed the bushing and went with a shorter bolt right against the alternator. Don't seem right as the F-type mount bracket is the same on these later models. Might be best to install with the clamp-up washer with the longer 3/8" bolt to alleviate some of the vibration. Good luck in maintaining your summer ride!
deanries (Go Big or Go Home)

mmwjr · 09-13-2015, 05:08 AM

Thanks for posting, cannot tell from the pictures but how is the pully alignment with the engine pulleys?

deanries · 09-14-2015, 12:53 AM

Quote:

Originally Posted by mmwjr

Thanks for posting, cannot tell from the pictures but how is the pully alignment with the engine pulleys?

Sorry Mike but I had already removed the belt. The F-type mount bracket is to be perpendicular to the engine and alternator pulleys. What I found on mine was that it was slightly out and had to shim the front bolt holding the bracket to the block. That was a huge help also to reduce vibration of the alternator, also will save the belt from wearing.
Dean (deanries - Go Big or Go Home)