Idler pulley bolt

[RJ Sprouse]

I have a 4.3 liter mercruiser mpi and my serpentine belt came off after we heard some squeaking. I think I found the issue. A bolt is missing that attaches the arm that holds the idler pulley to the engine. I have no idea how I find the correct size bolt for that hole.

 

[Thornton69]

Did you try fishing around in the bilge with magnet? You wouldn't want it to stop a bilge pump from operating.

 

[Fill Ess]

Most of them are 3/8-16 ...... you'd need a matching nut

Have you checked the parts diagrams at boats.net or mercruiserparts.com ?

 

[boatrboy]

Be aware - It appears to me that there is another bolt loose in your first picture by the dipstick.

 

[Bill Curtis]

Yup, just saw that too. Time for some general maintenance looking for loose bolts, wires and hose clamps.

 

[Scott215]

Nice catch guys

 

[Lazy Daze]

I would think 3/8-16, as well. Or, at least, that would be the most common.

But... there's plenty of other bolts on your engine that you can borrow... find one that fits and then take that to the store.

 

[Jimmy Buoy]

That looks like the belt tensioner pully too.

 

[Scott215]

Just give everything a good once over