mercruiser carburetor mounting bolt size

[tjordan]

Hello all - always get great help on this forum. Thanks in advance.
I am trying to remove the carburetor on Alpha Mercruiser 3.0L GM 181 I/l4 S/N 0M326113
but can't figure out what the bolt head size is. Plan to use a ratchet but none of the sockets are the right size.

Anyone know what the bolt head size is?

 

[Fishermark]

Re: mercruiser carburetor mounting bolt size

I'm not sure exactly - probably in the 7/16 - 1/2 range. May even be metric. Basically if your sockets do not fit, try the "other" - in other words, if you are trying to use a metric set, switch to standard and visa versa.

 

[Fun Times]

Re: mercruiser carburetor mounting bolt size

As you put the socket on the nut, there most likely will be a layer of paint over the nut that could give you a false feeling of the correct size.

You'll want to bring some 6 and 12 point sockets, as sometimes using both may help with the paint covering the nuts.

Sometimes a wobble socket adapter may come in handy removing a carburetor as well as a wrench.

Be sure to bring some metric sizes as well, I don't recall off the top of my head but you may encounter the size to be in the 10 through 13 mm range or it could be around the 1/2 inch size too. The throttle cable nut is 7/16.

 

[Bondo]

Re: mercruiser carburetor mounting bolt size

Ayuh,.... I'm thinkin' the carb studs are 5/16", which'd mean a 1/2" wrench,....
Or maybe 3/8" studs, 'n a 9/16" wrench,...

Throttle linkages I've run across are 1/4" studs, 'n a 7/16" wrench,...

If it's metric, All my bets are off,... probably 10mm, 13mm, 15mm,...

 

[tjordan]

Re: mercruiser carburetor mounting bolt size

Yep, 7/16. The paint was part of the problem. Also, needed a deeper socket to get down on it.
Awesome, thanks for the quick replies.

I've got at apart and soaking in carb cleaner.