2002 Optimax 135HP DFI - Alternator mounting

[dc1984us]

Hi, thanks for validating my account! I've been looking over the boards the past few days to try and determine if I have a missing or possibly broken part. I called up Mercury directly, and they tried to help but I'm not completely sure if their information was correct.

Anyways, I was boating a few days ago and the engine started to sputter and eventually stopped. I barely made it back in to my lift, and realized that my drive belt had popped off. This is my guess as to why I had the problem in the first place.

I have not yet put the belt back on, since I am not sure if the alternator mount/screw/etc may be broken. Specifically, if you look at the link below, part #23 (Hex flange screw), I don't see anywhere this would screw in. By the way, this link contains the part for my engine based on the serial number I have (starts with 0G61..).

<Edit- See Announcements>

If you look at the picture I attached, it kind of looks like a piece may have broken off possibly. This is what I have been trying to find out, but keep hitting dead ends.

The Mercury customer service rep I spoke to earlier said you put a nut at the end of the Hex flange screw, and it just sits in that groove. Is that really the case?

Thanks for any help or insights you all can provide!

[dc1984us]

Hi, thanks for validating my account! I've been looking over the boards the past few days to try and determine if I have a missing or possibly broken part. I called up Mercury directly, and they tried to help but I'm not completely sure if their information was correct.

Anyways, I was boating a few days ago and the engine started to sputter and eventually stopped. I barely made it back in to my lift, and realized that my drive belt had popped off. This is my guess as to why I had the problem in the first place.

I have not yet put the belt back on, since I am not sure if the alternator mount/screw/etc may be broken. Specifically, if you look at the link below, part #23 (Hex flange screw), I don't see anywhere this would screw in.

https://www.perfprotech.com/mercury-...6/40?model=131

If you look at the picture I attached, it kind of looks like a piece may have broken off possibly. This is what I have been trying to find out, but keep hitting dead ends.

The Mercury customer service rep I spoke to earlier said you put a nut at the end of the Hex flange screw, and it just sits in that groove. Is that really the case?

Thanks for any help or insights you all can provide!

I put wrong model number. Sorry about that. It actually is 0T44465.

[SilverFox579]

First thing need to do is remove all the belt and aluminum debris from your engine before running it again. Also, you need to check your compressor after you've removed all the belt and aluminum debris. To check, rotate compressor pulley clockwise by hand and confirm it builds pressure by the 3rd revolution (gets hard to rotate pulley). Then check to make sure you don't have any vertical or lateral pulley movement. If pressure doesn't build or there is lateral or vertical play, you have a compressor issue. A close inspection of the idler pulley assembly would be wise as well.

It looks like the bolt sheared flush at the block and caused the alternator to smack the idler pulley bracket. Look closely at the U-shaped recess, I can see the outline of the bolt where it sheared. This also gives rise to concern about the compressor.

IIRC, the belt should be replaced, at minimum, every 4yrs, or sooner based on visual inspection during annual service.

[dc1984us]

I see that now! Thank you very much for pointing that out.

So I bought the boat 4 years ago, with 325 hours on the engine (engine is 2002). I've put about 75 hours on it in 4 years, but I've never changed the belt. So, there is a good chance the belt is way older than 4 years.

I also will give the compressor a check as you recommend.

Once again, I appreciate the information. Any tips on extracting the rest of the bolt? My plan, since the bottom of the bolt actually sticks out below the boss, is to grab it with some vice grips and slowly try to extract it.

[JOE54]

to me looks like bolt sheared and wore a groove in block mounting boss , hope it comes out easy

[dc1984us]

to me looks like bolt sheared and wore a groove in block mounting boss , hope it comes out easy

Came out super easy. I put some PB spray on, let it sit for a few, and got thr vice grips around bottom and was able to easily turn it a bit to where I was able to get my fingers on it. Took about 10 minutes.

I also checked the compressor...no issues.

When the new bolt arrives, I'll slap a new belt on and let you all know how it goes. Much thanks again.

[dc1984us]

One more question. Should I use loctite when I put the new bolt in?

[EuropeanAM]

You bet! I'd be using RED Liquid Loctite.

[SilverFox579]

[dc1984us]

Just an update. I bought a new belt and replaced the broken bolt. The boat Has never ran better. This is odd though. The engine is quieter. Way quieter. Any ideas why?

[EuropeanAM]

Items properly secured and belt at proper tension would be my "guess".

[dc1984us]

LOL yeah that is what I thought the response would be. I guess the problem may have been brewing for a while and it came to a head when the initial problem happened. I'll definitely be adding checking my belt to my annual maintenance checklist.

Thanks again for the help. You all saved me probably a few hundred dollars in repair costs.

[SilverFox579]