Inliners International Forums General Discussion Engines Is my one barrel wore out?

On my 74, with a 250 6 banger. I think my carb might be tired, not sure? When I got it, I had to tighten the mid section and adjust as has been fine, until lately.

It has the ole monojet still on it. He put a rebuilt on it years ago.

I noticed lately its a bit harder to start when sitting, and stalls three times. After that, it starts right up. Just started doing this, I had it fine since buying it months ago.

But when pulling out, it stutters! Then once going along she is fine. Will take good throttle, and pull good. Just pulling out it is stuttering, hard to describe.

If this is the carb, I can't tell. I did find one local to me on the craiglist, its brand new, but he has a photo of the classic industries thing, and it says for 68-69. Don't know the difference between my 74 and a 69 carb?

If you guys think its my carb??? which seems to be, but the starting issues when cold and stuttering pulling out, I may change the fuel pump too.

Here's the add for the carb. his add says model 1319.....

https://pittsburgh.craigslist.org/pts/d/new-cylinder-bbl-rochester/6175847436.html

Looking on classic, mine calls for model 1335, I dunno if theres a big difference. Although says "arriving soon", its not even in stock.

https://www.classicindustries.com/product/1974/chevrolet/nova/parts/1335.html


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Welcome. Save yourself some aggravation here and just order a rebuilt unit from Rock Auto. Prices are fair and the quality is really pretty good. I have bought quite a few carbs from them. they also have a send in and rebuild option for carbs that they do not have a good supply of cores.

For a 74 250 its like $132.00 with a core return, $65 more if no core to return, and you get a guarantee.

Have you adjusted the set screw inside the hex-head end of the solenoid to adjust the base idle? After turning the solenoid to adjust the idle speed, turn the 1/8" hex screw inside all the way on the solenoid, unplug the solenoid, and then adjust the hex screw to get the base idle speed you need (425rpm on my '78 manual). To adjust the hex screw, make sure you have a wrench on the solenoid so you aren't turning the whole unit, just the screw with a Phillips head. Plug the solenoid in and recheck your idle. This usually helps the engine pop-off when you turn the key.

I didn't know Rock Auto sold them. I see the rebuilt the PO put on years ago, the numbers come back to a 1976 Chevy C10 manual tranny. I guess it was just a mix and match deal.

I hear good and bad with rebuilts, but I am willing to give it a try and see if I get a good one.

ah ow. I didn't know there was a screw in there. I don't recall seeing anything on the end of mine for except a electrical plug. Maybe a rubber cover, but then again, I could be wrong. Still getting to know the car.

I was just turning the whole solenoid. Ugh!!
I unplugged mine to test it. I have voltage to it, but it doesn't work. I will try and do what you just said though. I had no idea there was a screw inside that solenoid.

I'm not sure anyone knew about that. I saw the 425rpm base idle speed on my tune up decal and asked how you set that on the forum. No one who responded knew how to set that, and my Chilton manual didn't have clear instructions on that. IntegratedJ78 tinkered and discovered how to set it, and it made a big difference for startup for him (he has a Rochester 2GC with an adapter on it now).

Like I said in the other thread, hold the solenoid still with a 9/16" wrench. Use your 1/8" Allen wrench (I just noticed I said Phillips head above just now) and turn the hex screw in all the way. Then disconnect the solenoid wire, and then back out the hex screw until you get the base idle you want. Reconnect the wire and recheck your initial idle speed. Hopefully that helps and you don't need to get another carb.

I don't have a new Imagr account set up yet, otherwise I would post a pic of the end of the solenoid so you can see the screw inside the end of it.

I like them better than photobucket that I used forever. Doesn't get as finicky, and works nicely.

Thank you, I am going to try that. Although my solenoid not functioning, don't know if that will make a difference? I did test the wire, there is power to it. Just quite working.

That fluttering is on occasion, when under throttle demand, then clears up, after rolling along pretty well. Doesn't even do it all the time. Just enough to make me aggravated enough to want to make it right.

try buying the "Rochester Carburetors" book by Doug Roe published by HP Books Amazon or Barnes & Noble usually have them--it has excellent chapter on Monojets so you can desmog them and make them into pretty nice carbs. As far as buying another carb always go with the oldest one as it will generally have a lesser amount of smog technology/voodoo built-in to it. back to the book--try to get the first printing it carries the ISBN number 0-912656-10-7 mine was printed 11/73 it has the most Mono-jet info than the other printing http://www.ebay.com/itm/Rochester-Carburetors-Doug-Roe-1973-book-Quadrajet-Two-Barrels-Monojet-4GC-/201990537354?hash=item2f0793008a:g:24IAAOSw539ZbeT9&vxp=mtr this is the cover of the book you want, NOT the one with the black cover as it has 100 less pages

Oh, so the solenoid doesn't actuate? Hmmmm.....I'm not sure on the hex screw? Not sure on exactly how it works, I just know how to set it. If that's the case, then you need a new solenoid I would think. I gotta get that Imagr account stated.

The '73 edition? Would that cover the '74 to '79 Monojets too? I don't know what running changes they made in them during those years? They were done on the 250 in cars and trucks after '79, but the 292 trucks still used a 210cfm and 250cfm version until '87.

Ok, Imgur account ready. Here's a test to make sure it works:



Passenger side view of my 1978 Monojet.

Ok, that works. Here's some more helpful info:



Here's a closer shot of the solenoid. You can se the 9/16" hexagonal end for a wrench to turn it for initial idle speed. Inside it you can see the 1/8" hex screw to stick an Allen wrench inside the tip. To set the base idle speed, hold the solenoid with the 9/16" wrench and use the 1/8" Allen wrench to turn the screw until it seats all the way. Then pull the plug to the left of it while the engine is idling. Back off the hex screw with the 1/8" Allen wrench until you hit the recommended base idle speed. Reconnect the wire and recheck you base idle speed to make sure it hasn't changed.



Emissions diagram on the 49 state 1978 250cid. I'm not sure how different yours is from this. My comments I added to this are for a Holley-390cfm/Offy/Stovebolt swap. The goal of keeping the EVAP, PCV, and vacuum advance after the swap (even the Thermac air cleaner too if wanted).



Here's a labeled pic on how everything is attaches to the carb.