Carter YF Carburetor

Don't really want to get into a lengthy discussion regarding the pros/cons of replacing the YF. I plan to either rebuild or replace the YF on my 75 CJ5/258/1barrel.

This has been a pretty good carb, but it is not THE original from the factory. Sometime in the eighty's I swapped it out for another YF without removing the tag that came with the original..yeah, I know...stupid!!!

This one has 7065S stamped on the body and I was wondering if this is the correct one and exactly what's up with all the model numbers on the YF's ? The carb runs well/starts easily enough with a few pumps on the pedal, and overall does ok. My main problem is the gas smell after shutdown and fuel mileage. No puddles under the jeep and no signs of leakage around the gaskets.

I know absolutely zilch about rebuilding except that you have to be very careful with reassembly and adjustments. I can buy a rebuilt YF from Autozone for around a hundred. Do you think I'd be better off rebuilding this one or simply replacing with another; and if I replace is the 7065S the one I should look for ?

P.S. as you can see I plan on sealing off all vacuum lines as shown, unless y'all think otherwise.......Thanks for your input !!

 

I noticed that you don't have your distributor vacuum advance hooked up, that might be your problem. if you still want to rebuild one off a 258, i have one off my jeep if you want it.

 

Hi

I'm also interested buy this discussion.

What is the distributor vacuum advance ??? Is it a hose, and if so, where is it supposed to hook up ??

I have the same carb and the same holes are plugged, so tell me if I need to de-plug and connect something....



Bob in Sherbrooke, province of Québec

 

The distributer vacuum advance should be on a ported source.

Maybee that capped line at the bottom on the carb on the drivers side just above the intake? I dont know the ports on the carbs sorry.

 

Vacume advance changes engine timing based on load. If it is not hooked up then you run around with the base timing.

As for hook up.. There is a vacume diaphram on the distributer with a nipple. Run a hose from that point to the ported vacuum source on the carb.

 

the 7065 number does not appear in any of my Jeep books.
the model numbers vary due to mostly internal differences, jetting, etc,
but could also be number of vacuum ports or size of internal passages.
CA carbs would be different than the 49 state carbs due to emission regulations.
I always prefer to rebuild what I already have, unless of course obviously worn out/broken/damaged etc.
your vac advance for your dist should be hooked up to a ported vac source; usually around the carb mid section; to verify, no vacuum present at idle; but when throttle opened vac is present/felt from port.
If you feel vacuum at idle, look for another port.
If it were me with your fuel smell problems, I would relocate/reposition the fuel filter and line. The purpose would be to get it away/as far from the heat of the exhaust as possible. When you shut off, the heat rises and can really heat up the fuel filter, creating pressure/vapor and pushing fuel into the carb. This condition is sometimes referred to as "hot soak". An extreme condition of this would make the engine hard to restart, as if it were flooded ( it is because the extra fuel enters the carb through the condition described above).
Also, a lot of 258 engine fires are started by the deterioration of the hoses over the exhaust manifold.
Another thought would be to remove the large vacuum cap you presently have on the vent for the carb bowl; with this plugged, the carb can't "breathe". Typically, this hose would connect somewhere on the air cleaner housing,( long air horn of the housing) where the fuel fumes would be re-introduced and re-burned; later years went to the charcoal cannister for the same purpose/filtering of the fumes.
If this is not possible, I have observed a few rigs where a hose from this vent had then run over to the compartment elsewhere; the other end of the hose has a fuel filter attached to it, with the one end left exposed/open to the atmosphere; not saying this is the correct way, emissions and all, but could solve the vent problem.
Anyway, I don't think your carb is vented properly to contain/capture the fumes.
hope some of this makes sense

 

Do you have a carbon canister? If you do it might have a port on it labeled carb vent.

 

I have a 74 with a 258. I had a hell of a time trying to get the correct carb rebuild kit due to number confusion. My number I think is 7001 or 7007. I think it is 7001 I'll try to check tonight. Anyhow its the number stamped on the bottom half of the carb drivers side I think. Also I am not sure its the original carb that came on mine or a replacement so I don't know how accurate my number is. However My carb does not have a bowl vent on it. The port is not even present and it runs fine. I don't see why you would need one either, unless that carb is for a later model engine. I hope this ramble makes SOME sense.

 

The '75 CJ5 258 came with a charcoal canister, but it appears that it's missing on your vehicle. In your first photo, it would be visible at the back and bottom of the left fender (or right side as you're looking at the photo). It would be mounted underneath the washer fluid reservoir. In your second photo, the capped off vacuum port on the intake manifold should go to the charcoal canister. The charcoal canister simply captures fumes from your gas tank, and then burns it when you are driving. Shouldn't affect economy or fuel smell though - it's emissions equipment that doesn't affect power, there's really no reason to remove it.

If you smell gas after driving it, check your fuel pump for leaks - feel the bottom of it - if it's damp then that's your fuel smell problem. Replace the pump. This is a common problem that is easy to miss.

The plugged up port visible in your third photo is the distributor vacuum advance port - not using this will negatively affect your economy a bit. Looks like whoever took all this stuff off didn't understand what any of it was for.

 

Is there a solution to this condition when the canister is saturated? I have a strong gas smell as well, thinking this sounds like me, but no stalling.

 

There should be a fluid check valve under the right rear fender. This valve should prevent liquid fuel from getting to the charcoal canister. On the bottom of the canister, the filter pad must be kept clean in order that air is drawn over the charcoal to purge the fumes. A malfunction of either of these could saturate the charcoal and keep the vapor recovery system from working. The system is fairly simple and trouble free, so I'd first look to see that all the plumbing is present and intact, then check the components.

 

the filter pad Tim mentions is tucked up inside the bottom of the cannister; you have to pull it out between the "spokes" of the cannister bottom. It typically can get coated with mud/road grime and plug up.
the Jeep part number for the filter is: J3227279
this would fit the GM/Rochester type of cannister which is what Jeep used; maybe thru your local GM dealership as well

 

O.K. guys, obviously by looking at the pictures you can see that I have NONE of the emissions setup. Can my jeep run well without all of these devices or is it worth the effort/money to reinstall all of these to restore to original specs; and are these parts still available?

Also, I replaced my distributor with an early 80's GM HEI which improved the driveability considerability.(no more instant shut-off and trying to coast to the emergency lane and waiting till she wanted to run again!!)
There is a vacuum line coming off the distributor and I am not sure which tube it connects to. There are a total of FOUR vacuum tubes on the carburetor itself + two on the intake manifold...anybody know the routing for all these ?

Lastly...anybody out there with a 75/258; would you mind seeing what your YF model number is and passing that along. It is imprinted on the base of the carburetor on the manifold side.I am leaning towards getting a rebuilt but I want to make sure I get the right one.

Thanks for all your input, I feel like I'm making some pretty good progress these days !!

 

1975 YF Jeep carbs
7039 - full size Jeeps
7040 - CJs, except Calif
7041 - CJs, Calif
7043 - full size Jeeps

 

As far as emmisions setup. I say just hook up the vacuum advance to ported vacuum, pcv valve, and the EGR valve system and thats it. I know in 74 they had a transmission controlled spark (CTS). Good luck finding switches and wiring for it though. The emmisions were still primitive back then, and most of the stuff under the hood was designed without it in mind. So the motor should run fine without it. I would replace the carb with the proper one for the year and motor though. FYI none of the emisions are connected on mine and I priced out the CTO switches for about $30 a piece so it gets expensive quick. Mine runs just fine without it.

 

I appreciate all the help. This afternoon I stopped by a salvage yard and found the charcoal cannister off of a 82 Cherokee. Seems to be in great condition..paid $6.82 for it and the bracket. Very cool !!

It has 3 ports..two on the top labelled TANK and CARB BOWL and one dead center on the bottom with a cap that pops off exposing the filter pad jpflat2a referred to. I know fuel tank line attaches to the TANK fitting but not sure about the CARB BOWL. I believe it goes to the large fitting in picture two (first post) just to left of the fuel inlet coming off of the fuel filter. Am I correct ?

Lastly does anything attach to the bottom port on the cannister or is it left open to breathe......Thanks everybody for your help !!

Hopefully this will correct my fuel smell problem. Also the vacuum advance hose off the HEI is currently connected on the backside of the carb(see picture 3 on first post); opposite the 7065S imprint. I will check to see if this is a port that has suction with RPM load....

Will try to find a way to isolate the fuel filter from the manifold heat, but not a whole lot of flexibility with the steel tubing. I can definately raise the filter so that it is about 2 inches furthur away from the manifold so that might help. Looks to be an interesting project shaping up !!!