Flame Arrestor Stud Turns Trying to Remove Nut

[rstyll]

I had work done on my boat last winter, and the mechanic put the flame arrestor nut on without inserting a washer between the nut and the black cover. I went to fog the engine to winterize, but I can't remove the nut to remove the cover. It seems the mechanic tightened the nut too tight. The flame arrestor stud just turns instead of the nut. I was able to tighten the arrestor stud all the way, hoping to get it tight enough so that the nut would loosen, but it just keeps loosening the arrestor stud. I thought if I kept loosening the arrestor stud, it would eventually come out so that I could remove the arrestor and cover, but the stud doesn't seem come out after several turns to the left.

Any ideas how to loosen the arrestor nut from the stud or the stud from the carburetor given the nut is stuck?

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Whatcha workin' on,..?? Merc built tons of motors,.....

 

[rstyll]

It's a Mercruiser 4.3LX Vortec with a 4 barrell carb.

 

[Fun Times]

It's a Mercruiser 4.3LX Vortec with a 4 barrel carb.

Did the stud feel like it was coming up as you turned it?

Being the engine year of around 1997? The stud should look like item # 4,
http://www.mercruiserparts.com/Show...esc=CARBURETOR+AND+THROTTLE+LINKAGE(4+BARREL)

Can you grab the first top thread of the stud with small vise grips to turn the nut just to get it started then maybe put some side pressure using the flame arrestor to help hold the stud while trying to turn the nut.... I recall there isn't much room between the top of the nut to the end of the stud but maybe there's a bit more with the washer missing?

That mentioned, I've seen many slightly cracked black covers over the years and a bigger washer to help hold it back down.:suspicious:

 

[rstyll]

The stud did come up some turning it left, and the cover started to push up against the wood/carpet framing above the back of the engine. I turned it left for a minute or so, but it would never fully release and pull through. I would have thought it would have seemed very easy to turn at some point when it releases, but it continues to feel like there is a little resistance. I've seen videos of the stud being removed with vice grips from the carburetor, so it's bound to come out. I suspect the wide flange/ridge around the stud at the bottom of the top threads keeps it from pulling through the flame arrestor and cover, so maybe it's just the cover and arrestor not being able to move up any more due to the wood framing.

Yes, it is a 1997 4.3 Vortec, and thanks for the link to the parts diagram. I think there is just enough of a tip on the stud I might be able to grab with vice grips. Good suggestion. I'll likely need to buy a new stud and nut, but I have all winter to do that. Ha.

My black cover is cracked as well, and was that way when I got the boat.

Fun Times, thank you for your help. I'll give it a go.