rochester 4bbl loose throtle body screws

sarantis

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Feb 4, 2007
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436
Although the carb was rebuilt three years ago by a car mechanic now that i decided to rebuilt it myself i found that the two screws at the throtle body were significantly loose.I noticed also that they didn't have the washer that forbids loosening ( sorry i don't know how it's called) in comparison with the 9 screws at the top of the carb.Were they missing?Should i buy two washers and put them there or use loctite at the threads? (does Loctite stand with gas?)
Thanks in advance
 

solar7647

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Apr 23, 2009
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1,218
Re: rochester 4bbl loose throtle body screws

They are Lock washer. If they indeed need them yes replace them, i dont think lock tight would be a good idea though.
 

JustJason

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Re: rochester 4bbl loose throtle body screws

Those screws are never meant to come out. As in never ever, not even during a rebuild. They really need to be peened over if you plan on re-using the throttle plate. They have to be mechanically held in place by peening, not chemically.

It's hard to do even with supporting the shaft with something without wrecking it.
 

sarantis

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Re: rochester 4bbl loose throtle body screws

i think you misunderstood or i was not so clear . i talk about the 2 screws at the botom that hold the throtle body assy to the bowl assy.
 

JustJason

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Re: rochester 4bbl loose throtle body screws

Oh those screws... just put them back together according to the book with the correct parts and torques and throw a dab of perfect seal on the threads and they won't back themselves out anymore.
 

sarantis

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Re: rochester 4bbl loose throtle body screws

When you say " with the correct parts "you mean there should be washers for those two screws? Sorry i don't have the book, i follow Alpheus' videos,merc service manual for 5.7 and the kit's insructions to rebuild it.
 

sarantis

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Re: rochester 4bbl loose throtle body screws

ok if somebody remembers if his rochester carb has lock washers at those two screws please let me know.
 

JustJason

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Re: rochester 4bbl loose throtle body screws

go to www.mercruiserparts.com and follow the links and pull up a parts diagram of your carb, it will show what hardware is supposed to be there.
 

thumbdoctor

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May 8, 2010
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Re: rochester 4bbl loose throtle body screws

ok if somebody remembers if his rochester carb has lock washers at those two screws please let me know.

No the throttle base to float bowl doesn't have lock washers on the screws. You will also notice that they are Phillips head. The auto mechanic who rebuilt the carburetor probably tightened them well. The thick bowl to base gasket tends to shrink over time leaving the screws loose. Loctite on the screws won't help as they will still not be clamping the parts together when the gasket shrinks. Putting lock washers will provide a little bit more clamping pressure along with the 2 long rear screws (with lock washers).
 

Black as

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Feb 22, 2010
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Re: rochester 4bbl loose throtle body screws

I just rebuilt my 4 barrel Rochester and funny enough those bolts were missing I bought some new ones and loctite them in without washers.
 
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