Lock washers, flat washers or star washers, are they not used on marine applications?

flyman219

Seaman
Joined
Jun 2, 2010
Messages
55
I had a couple of bolts back off on the thermostat housing on my 3,0 today. The motor started to run bad, lost the alternator, temp gage showed 100 degrees after running all day. We got back to the marina and we were pumping a lot of water out of the bilge. When we had a chance to open the cover I noticed that the two blots holding the thermostat housing to the block had backed off and I was flooding the motor compartment. I just did a valve job n the motor and I'm not above thinking I might have snugged the bolts but not fully set them. The funny thing is that I started to think there are no lock washers or flat washers on most all of he bolts on marine motors. Is there a reason for this? Being familiar with automotive motors there are many lock and flat washers used. So should I add a washer or use some thread sealant or just set the bolts and call it good?
Mike​
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,092
My guess you forgot to tighten them, rarely do they just back off
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
flyman, actually there is a torque spec for every bolt and nut ever made. So if you want to take the time and research the correct torque for such bolts go for it. It is usually not specified for general bolts and nuts but more so for head bolts, connecting rods, flywheels and such things. But there is a certain torque spec for every usage in any place they are used. Usually though the person tightening such bolts tighten them to more then the required torque by their own tightening method and don't know it. But you have to actually tighten them for them to stay and not back off. JMHO!
 

crazy charlie

Vice Admiral
Joined
May 22, 2003
Messages
5,352
those bolts did not back off if tightened in the first place...no way !! I believe mine have both washers and lockwashers Charlie
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,464
Ayuh,.... I too, gotta believe ya ran 'em in, 'n forgot to set 'em,....
 

flyman219

Seaman
Joined
Jun 2, 2010
Messages
55
I have to agree that I must have just snugged them up like everyone has suggested and then adjusted the power steering belt tension and I did not come back to torque them down after that. I got all the water mopped up now and everything is running like it should, lucky for me it wasn't any worse than it was. When I first opened the cover with all the water everywhere I wasn't sure what happened seeing as the hoses were all intact and attached.

Mike
 

San_Diego_SeaRay

Petty Officer 1st Class
Joined
Nov 9, 2014
Messages
337
I've found that one of the most useful tools available to us DIY'ers are "exploded views" available with a little searching on the internet. For instance, if I were in your shoes I would have gone to THIS site (actually I have a 1983 Mercruiser MCM260 so I'll use that as an example). I would have then clicked "Search With Pictures", then "Mercruiser Sterndrive & Inboard (Includes Diesel) & Mercury Racing", then "V-8 Sterndrive Engines", then "260 (4 BBL.) GM 305 V-8 1982-1986 ", then "6218462 THRU 0B525981", then "STANDARD COOLING SYSTEM". I can then see that there clearly should be a lock washer on the TSTAT housing bolt (Part #12). You might try your engine and might find the same thing.

And by the way, there are TONS of washers all over my engine. So no, I don't think marine applications avoid them.
 
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