unidentified screw

Ken Heyman · October 11, 2010, 02:52:27 PM

I found this (the screw-not the hand) at the bottom forward edge of the engine compartment. It does have some factory paint on it.Anybody have a clue before I hunt for my exploded engine diagram? The only recent maintenance was the wiring harness upgrade and a alternator belt replacement. I hate having extra unused parts.

Thanks in advance,

Ken[attach=#]

Indian Falls · October 11, 2010, 03:06:11 PM

There are 2 like that on my intake silencer. Mine has the can with the shredded aluminum sieve, not an actual air cleaner, for the engine air intake.

Ron Hill · October 12, 2010, 05:45:52 PM

Ken : That bolt looks to have a 1/2" or 7/16" head??
If it had a 9/16" head I'd say it was the alternator thru the upper bracket bolt. A thought

Stu Jackson · October 12, 2010, 06:13:00 PM

The alternator bracket is held on with studs, not bolts. Have you looked under your air filter? Could be the bolt holding that.

horsemel · October 12, 2010, 06:38:29 PM

I go with Stu on the air filter. I had mine apart a few weeks ago and that looks like the screw.
Mark Mueller

SeaFever · October 12, 2010, 07:06:11 PM

Ken,

Bolts similar to this are used to secure the gear case to the engine. If you are not familiar with the gear case, here is some explanation. If you are looking at the engine from the side where the pulley and the alternator belt are than the cover on the engine facing you is called the gear case. The gear case has altogether 12-13 such bolts. Out of these majority are of one length only 2-3 are of a longer length as far as I can remember. The right side of the gear case (the side which as the alternator) is shaped like "mickey mouse's ear"...

As others have said above, the same kind of bolts are used on the coolant manifold and also on the intake manifold.
Attached is a photo take during my re-power and shows the front of theM25 with the gear case just behind the main pulley. When you do find the place the bolt came from I would recommend using medium strength Loctite to put it back. Also make sure the threaded end of the bolt is intact and that it has not sheared off!

Hope that helps. Let us know what you find...

Cheers.

Ken Heyman · October 13, 2010, 06:14:42 AM

Thanks much guys. I will investigate all your suggestions. Fortunately we wound up the 2010 season without mishap (at least to my knowledge) due to the missing bolt. I will let you know the result.

Thanks again,

Ken

SeaFever · October 25, 2010, 01:29:13 PM

Ken,

Just curious, did you find where the bolt came from?

Cheers.

Ken Heyman · October 29, 2010, 05:04:43 AM

thanks for the inquiry!,

I haven't been on the boat in a few weeks as it is currently on the hard and we are out of town. (currently feeling envious of you guys that sail all year around.) I will take a look in the areas you suggested, when I get back down to the yard, and will advise.

thanks again,

Ken