yet another carter yf/f-134 problem....

Ok....so when I got the jeep, they had it set idling at 1000 rpms, (it idled great there). I knew that wasn't right, so I adjusted it down and could get it smoothish down to about 750, (I know its supposed to be at 600). Well....Now I have changed some things: new plugs, wires, cap rotor, PCV valve, muffler, (the muffler it came with exploded out the top, and it looked new too). The cherry bomb I put on it gets hot on the top now, and has burned all the paint off to bear metal, I can't get a smooth idle at anything below 1000. It hesitates when I first hit the throttle, but runs great after 1000 rpms. The exhaust setup is kinda botched together because I had to do it in a hurry and on less than a budget. So why can't I get it to idle smoothly? It sputters just a little every couple of engine revolutions, not quite a mis, or a backfire, but sounds like a very minor version of either/both. Any help would be great, this is driving me nuts.....

 

Sounds like possibly a vacuum leak causing a lean condition. Also check and see if the advance mechanism in the distributor is working correctly.

 

The distributor is a vacuum advance iat-4405, so I assume its working ok. I don't have a dwell meter, but the points/condensor were new when I got it. I did the "spray carb cleaner all over everything" vacuum check method, and got no change in idle.

 

How should I go about trying to set the dwell without the dwell meter? Is there a way to do so? Any other tips on searching for a vacuum leak without a vacuum leak detector? (aren't the PCV line and the carb itself the only possible vacuum leak places on this thing anyway?)

 

Assuming points are set correctly and there is no vacuum applied to the distributor advance unit at idle you may want to take the time to check/adjust valve lash before you spend anymore time on the fuel and electrical system.

I hope not but you may have a valve job on the horizon.

 

I guess maybe I should find a way to get a feeler gauge to do these adjustments. I will admit that I haven't even looked at the valves, but I was hoping it was something easier....(hence the new ignition components and such)....

 

New points? gap at .020?

 

Ok, going to get new points and a feeler gauge....Then I guess its on to checking the valves......

 

Exactly the same conditions I got my Jeep in.
I'm agreeing with everyone else and adding some.

Without a dwell meter, timing light, vacuum gauge, it's tougher:

As said, set the points with a feeler to 0.020", no less, a little more is ok. If no feeler, use the matchbook trick.

As said, set the timing to at least 5° BTDC. Mine was set to idle at 1000 rpm when I got it because it was 10° RETARDED.
If no timing light, advance it till it will idle at ~700-800 rpm. If that works, run it at speed, if you run out of power around 3000rpm, you went too far with the timing and need to retard it immediately.

After that, if you think the YF is a prob, I solved all my YF probs by running ~4 bottles of fuel injector cleaner in ~2 gal of gas, then continued running cleaner in each tank for several tanks. Fortunately that worked for me and eliminated a rebuild.

 

I'm always nervous about messing with the timing without a timing light....I will get the new points in (won't a correct point gap mean a correct dwell?) and then maybe see if I can get it to smooth out with some distributor tweaking, (I usually don't even run to 3000 rpm though, since I was under the impression that it redlines at 3200)....Then I guess I should move on to the carb.....Did you use the cleaner that you run straight into the fuel rail for injector cleaning, or just the additive stuff?

 

The f head was designed to run at a max continuous speed of 4k rpm, I tend to use 4k as a redline and max cruise of 3800.

I use Chev Techron in the bottle cuz it's cheap at Costco.

 

A quick search at Amazon will find a timing light and dwell meter for ~$25 ea, and a vac gauge for ~$11 with free shipping

 

You can really run it at 4k? Everything I've heard has said that it redlines a little over 3k, and to not run more than 3000 for any period of time.....do you know of any links to verify any of this? I usually run between 27 and 2800 on the freeway, (about 48 mph), but if I can go faster it would be great....

 

LOL