All Small Six 250 i6 carburetor help

[Trey Stanaland]

Hello everyone I'm here for help on my buddies 1970 mustang coupe with the 250 i6. To make a long story short the car came with a carter rbs which the fuel mixture screw would do nothing to. Rebuilt the rbs and the same problem so I went the cheap route which I thought I was saving money at the time to get a "new" rbs off of Amazon. Which turned out to be a piece of china garbage. I'm not saying that the rbs is an over all bad carb it has just burnt me and I want something different. I was deciding on either a autolite 1101 or a carter yf or yfa. Or any other good carb that would run well on this machine. Also do yall think either of these carbs will require modification to the throttle linkage? I appreciate all the help and guidance yall have for me

 

[comet6]

If the step up diaphragm is not seated/sealed correctly during rebuild it will cause overly rich condition and idle screw can be turned all the way in won't correct. What exactly is the symptom ?

 

[PSIG]

Lots of info, settings and troubleshooting:

Carter RBS 1 Barrel Carburetor Technical Help

www.carburetor-parts.com

One thing I've found with carbs, is if you skip or say "good enough" with any of the adjustments or spec's, it will bite you in the ...

 

[powerband]

since air/fuel idle mix screw was ineffective, also check for vacuum leaks if you can , sometimes simple problem with PCV plumbing.

some carbs like the YF may have same linkage but usually needs a little help with non- OEM carb used. The Maverick has a cable throttle that easily adapts to any setup.

the 250 can stand some range of carbs on the large side of 4 or 6 cylinder and small 2Bbl's are a popular option,

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250 carbs
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(" 'heard Carburetor is French for Don't F&^k with it" )
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[John Ha]

Welcome! I've been down this road with mine, although mine is a 250 from a 73 Maverick in a 66 convertible Mustang. I agree with the vacuum leak assessment. Get some carb cleaner from your local auto parts store and spray it around the base of the carb. If the idle changes, you have a leak there. Also check your hoses (PCV, power brake, distributor advance, automatic transmission modulator) to ensure that they're not cracked or broken, and confirm that none of the vacuum users (power brake diaphragm, distributor advance, etc.) are not internally damaged and leaking.

Rockauto sells remanufactured RBS carbs. The company that does them is Autoline in Canada. They do good work and stand behind their products too. The first one I got from them was warped at the base and I could not get it to seal to the intake. They exchanged it for a different one, which is working fabulously. I highly recommend going that way.

 

[Trey Stanaland]

So I have done the vacuum leak assement several times before but havent found any thing both on the first and second carburetor. The only one I have not checked fully would be the on going to the transmission. Haven't even thought about it though. I may try another rbs havent decided yet I reckon. Do yall like rbs's?

 

[Trey Stanaland]

If the step up diaphragm is not seated/sealed correctly during rebuild it will cause overly rich condition and idle screw can be turned all the way in won't correct. What exactly is the symptom ?

Running terribly crappy and rich. Plus now having to keep preassure on the throttle so it stays running. Then the radiator got a hole in it and haven't made it any farther!

 

[Trey Stanaland]

I have decided to get a professionally remanded carb that John Ha informed me about when it gets here I will give an update on the car. I appreciate all the help and information yall have gave me! Look forward to getting this car driving again!

 

[Trey Stanaland]

Welcome! I've been down this road with mine, although mine is a 250 from a 73 Maverick in a 66 convertible Mustang. I agree with the vacuum leak assessment. Get some carb cleaner from your local auto parts store and spray it around the base of the carb. If the idle changes, you have a leak there. Also check your hoses (PCV, power brake, distributor advance, automatic transmission modulator) to ensure that they're not cracked or broken, and confirm that none of the vacuum users (power brake diaphragm, distributor advance, etc.) are not internally damaged and leaking.

Rockauto sells remanufactured RBS carbs. The company that does them is Autoline in Canada. They do good work and stand behind their products too. The first one I got from them was warped at the base and I could not get it to seal to the intake. They exchanged it for a different one, which is working fabulously. I highly recommend going that way.

Got that new carb and radiator and low and behold it's alive appreciate the information on those rock auto carbs! She's just skipping terribly now pvc hose seems to be alittle big dont know how I havent noticed it before. Ima get me some hose clamps and seal up those gaps.

 

[chad]

for me? sometimes 'fuel problems' R really "ele".
Do a full ignit tune (to learn if not familiar AND to rule out). Then go on to carb tune.
RBS has pressed in jets so hard to play with. Mike's carbs (go dwn the #s list) can ID if
U have a nash, amc, ford, etc carb (different displacement/wrong jet). I like the carb as the
larger the 1v the more tq (C avitar/signature). 2v (esp "direct mount") R for the racers (HP) &
my fav is the 2100. Lots to play w/there but holds a set-it-&-forget-it too. progressive? weber 32/36?
comes after the 2100 for me.