1972 c10 307 carburetor options?

[JulioK]

My first post here so be gentle with me..

Recently bought this c10 and am really enjoying it! I'm told the carburetor is in need of replacement and it shows in poor throttle response. I am not interested in hyped up performance and really just want to have it accelerate from a stop smoothly and maximize mpg. It has a Rochester 7042105. Should I buy an identical replacement or look to another manufacturer? I'd rather not get in to changing the intake.

[DjS71]

Assuming it isn't cracked or held together with duct tape and old wire, are you opposed to rebuilding it? Should be able to get a kit @ a fair price from a local parts house. I got mine from NAPA and it took me about 90 minutes total including 30 for soaking in the solvent bucket. Snap a few quick pictures of the linkages before you take the carb apart, nice to have a reference when you go to put it back together.

Might think about moving to an external fuel filter too, the stone job in the carb body has a much smaller surface area and will clog easier if there is any debris in your system. There was in mine, but my gas tank looked like a sieve after I had it dipped.

Clean rig you got there, enjoy.

Cheers,
Dan

[Tx Firefighter]

Find a better mechanic.

It sounds like this one is afraid to take on the job of fixing what's wrong with your current carburetor. Like was said, barring the casting being broken, it can be fixed. A rebuild kit and new throttle shaft bushings should fix any issues.

Also look towards tune issues. Timing, ignition system, etc.

That truck is nice enough to deserve it.

[hugger6933]

Welcome to the site from AR. The carb on your truck is about as simple as it gets to rebuild unless like stated above it is cracked and that has happened before. The only other main issue if I remember right is the main throttle shaft might get a little sloppy and need bushings installed.If indeed that has happened it may leak gas there or create a vaccum leak. Jim

[Aussie Ol' Blue]

Sweet lookin truck. good luck.

[JulioK]

Thx for the input. I've had a few shops take a look at it while doing some other repairs and they've all suggested that replacement rather than rebuild was the better choice. It does have an external fuel filter and has been converted from electric choke to manual. I have to run with the choke pulled open about half way all the time to keep it from faltering from a stop (I swear it is not my lousy technique with the three speed). With the choke cable pulled the idle is racing a bit.

[geezer#99]

Forget about the carb. Optimize your timing. Most carb troubles are timing related.
Take some pics of your carb with the air cleaner off. There were manual choke models of your carb.

[bMr]

Was electric choke available on a '72?

It sounds a previous owner might've rigged up a mess and that's why these mechanics suggest a total replacement. Honestly, as much as labor costs these days you might be money ahead with an original replacement rather than paying them to undo the fixes of a previous owner.

That being said, barring a catastrophic failure (or a hatchet job!) most carbs can be rebuilt quickly and inexpensively. This site has many parts for that unit including a rebuild kit for under $30, http://quadrajetparts.com/rochester-...iac-p-418.html


I grew up thinking carburetor was a French word that translated into "do not touch." But with a manual and some patience they're actually pretty serviceable.

[Lou Boffa]

these guys are right; timing and a good carb rebuild will do wonders. I had my Rochester 2GV rebuilt and the truck runs like a deer. Lots of good board members in the Nashville area. I'd rely on them for where to find a good shop.

[JulioK]

Here are pics. You can see the old electric choke that is not connected electrically and the other pic shows the cable for the manual choke

[JulioK]

Oops here is the pic

[JulioK]

Pic 2

[thefraze_1020]

Take a browse around this site:

http://www.carburetor-parts.com/

He's in Washington State, but Mike is the expert on carbs. He has info on the kits you need to buy, and how-to's on how to rebuild.

That truck is a beauty!

[magwakeenercew2jh]

Flip(s).

[geezer#99]

Do you know what your timing is set at?

[bMr]

Are two mounting bolts missing from the base plate?

[geezer#99]

Originally Posted by bMr

Are two mounting bolts missing from the base plate?

No!
It's likely a small base type.
THe large base used four.

[bMr]

And yet it looks like there are four holes...hmm.

[geezer#99]

Originally Posted by bMr

And yet it looks like there are four holes...hmm.

You got good eyes!!
Four in the carb but only two in the gasket!
Why you ask!!
Bean counters would be my guess!
http://www.carburetion.com/Products/...aspx?part=G841

[bMr]

Apologies for the sidebar JulioK.

You came here asking about replacing the carburetor, but what everyone here is trying to get at is that it sure would be nice to verify whether this problem you speak of is inherent with the carburetor before you spent money replacing it. I know I'd sure hate to spend money replacing a part for the sole purpose of fixing a problem--only for the problem to lie elsewhere!

There could be several things negatively impacting the performance of this engine but your description of using the choke to keep the engine running seems to indicate an air/fuel ratio imbalance. Obviously this is primarily the job of the carburetor but other parts, or parts failures, can have an effect too. If it were my truck I’d first check for vacuum leaks and then go from there.

All that being said, several mechanics have personally laid hands on this truck so they immediately have a leg up on all of us!

[JulioK]

Thanks for all the great stuff to consider! I will try not to jump to conclusions on the carburetor. I am gonna research vacuum tests for carburetors now.

[geezer#99]

THere's an old rule you need to remember!
'Timing first, carb second'!!
Research your timing first.

[GASoline71]

And the "electric choke" you are referring to... isn't an electric choke at all. It's part of the emissions "spark knock controller". About 90% of them have been removed by one owner or another. But, like on yours, they still pop up now and again. I had the same gizmo on my 4bbl Q-jet on my 1972 GMC. I removed it with no problems affecting the engine whatsoever.

If you're having to use the choke to keep it running, I would first off suspect a wicked vacuum leak. Which any mechanic worth his salt in a shop should be able to find in a NY minute.

Beautiful truck BTW...

Gary

[hamjet]

I don't see where there was a choke on it according to the pix. that solonoid on the driver side is either a CEC solonoid,( if it has two small hose ports on the end of it) or its an idle solonoid (if it has electrical connection on the end). I cant tell by the pix cuz I cant see the end of it, but it looks to be an idle solonoid to me....http://carburetor-manual.com/rochest...alve-a-42.html

[geezer#99]

Everybody's going sideways!! LOL!!
The op said he had an electric choke converted to manual.
I suspect he doesn't know the difference between a divorced choke (which he had), a hot air choke or an electric. JMHO!!