Cylinder head studs for fuel rails.

[Bob G.]

Didn’t want keep adding to my other post that is primarily for the powerhead project.

Had time to pull the thermostats and test today. First time. Pulled the port thermostat and when it opened, a piece of grass came out. The gasket broke when took the cover off and replaced. Got the port side back together.

Went to loosen the starboard fuel rail nuts. The top one was tight, the cylinder head stud for the bottom one was backed out. I unscrewed the stud and clamped the shoulder part in a vice between 2 small pieces of wood and got the nut off. I’ll need to find 2 skinny nut to get the stud back on tight.

I’m not seeing a torque spec in my manual. Also wanted to know if it needed blue locative on the threads, that are bare.

Thanks

[Bob G.]

Got two M10-1.5 nuts at the local hardware store. Double nutted the stud and installed. Removed the nuts and installed the original nylock nut. Torqued bot nuts to 35 lb-ft. Will remove the starboard thermostat tomorrow to test/clean.

Would still like to know the stud torque spec and if it needs blue loctite on the threads. Not sure how long stud has been loose as I’ve never loosened them to remove the thermostats.

[castforcash]

Wouldn't hurt to put blue loctite on the stud. Not sure what the torque spec is for reinstalling the stud.

[SilverFox579]

You'll be fine with how you reinstalled it, a bit of blue thread locker might have prevented a repeat if you needed to pull stats in future.

[Bob G.]

Went to loosen the starboard fuel rail this morning to pull the thermostat and the lower stud came out. Installed with the 2 nuts AND blue loctite!

Had grass in both thermostats. Both gaskets broke during removal and replaced.

[EuropeanAM]

Technically you use RED liquid loctite on the stud, and bottom it out tight. Arguably, it can torque to the same setting as the nut (but I'm not overly keen on doing that as it is bottomed out in the threads, meaning thread damage is a possibility if it's too tight).

[Bob G.]

Thanks Don.

Any reason why the stud had no Loctite at all on it? I'll use red Loctite if any of the others come out when loosening the fuel rail nuts.

[EuropeanAM]

Probably not the first time it had come out.

[Bryanmc57]

As an aside, the only time I ever had a rail stud back out was when I was taking the nuts loose on a warm engine. Never had it happen on a cold engine.

[Bob G.]

This was the first time I removed the fuel rails since I bought the boat used in 2012. Boat/motor have not been in a shop since I owned it.

I've learned to do the general maintenance myself thanks to this forum and everyone that contributes with advice. Having a Mercury Manual and Diacom software is a plus too.

[JOE54]

^^^^ +1 agree

[SilverFox579]

+2!