Bogging out at idle after driving for an hour...

Been offroading twice this week and both times the Jeep ran great for the first hour or so and then it would start to choke down while idling and the amp light would come on, but it would never cut all the way out. Got it home tonight and it looks to have something to do with the throttle knob on the dash. Is this something that needs adjusting? What else could it be? It runs fine on the street and only does this after being on the trails for awhile. And when I get back home it will be back to normal after it sits for a little bit. It's not running hot or anything. What else should I be looking for? This is a '64 with the f-134 engine, by the way. Thanks!

 

Maybe trying to vapor lock? Does you gas line run close to any heat sources?

 

No it's not near any heat source other than the valve cover where it connects to the carb. What exactly is vapor lock anyway? and the fuel filter is located right next to the carb. Is this the proper location? And I was wrong earlier saying it was the throttle knob that was part of it. It turns out it's the choke knob. If I play with the choke lever on the carb while it's acting up, it starts to idle better.

 

vapor lock is the vaporization of the liquid gasoline before it reaches the carb; it is caused by engine/exhaust heat build-up.
Ideally you would like to have the fuel lines positioned away from the engine/exhaust heat sources as far as possible.
Heat rises, so the positioning of your current fuel filter could be the source.
Personally, I like to have the fuel filter positioned right before the fuel pump; keeps crud out of the fuel pump and keeps cooler in the lower position with better air flow from the engine fan.

 

Ok I can try to relocate the filter. But my fuel pump is mounted on the frame below the driver's seat. So it would be ok to place the filter right before that?

One more question...where is the oil filter located? I can't find it. I really need to get a manual. lol! Thanks for your suggestions.

 

Do you have a carter YF carburetor?

It may need a rebuild. The YF can have what appears to be intermmittant problems.

Try this link - http://www.earlycj5.com/forums/showthread.php?t=31838

I always go to the carb first when I am having any problems with an F-134.
The YF is a great carb, but it will not tolerate either a mix-mash of parts or the wrong parts internally.

The F-134 carb was a different animal from any other YF carb used on other applications.

I may be able to describe your 'bogging' without seeing the jeep.

It doesn't want to idle well. It'll stall, but re-start, and if you maintain RPM's higher than idle it will run, but let off the go pedal and it goes to idle and dies.

Sometimes you can see fuel dripping from the carb, but not always.

Sometimes the idle seems to be higher than it should and other times it idles lower.

After going over a bumpy road or using the jeep for a while it gets worse, or appears, but other times it is OK.

All of the above indicate carb problems.

I posted in the above thread a source for a good carb kit and my strategy for fixing a badly perfoming YF.

It is really quite easy and straightforward....


kamel

 

Thanks kamel! Your description pretty much hit the nail on the head of the problems I'm having. I will check out the tread you posted and see about rebuilding the carb. And yes it is a Carter YF carb. Thanks again! Here's a for you!

 

good luck.

Here is a piece of advice in a rebuild of the YF.

Some people think that if they can get a couple of YF's or they might have a couple of 'em laying around, that they can take them all apart and 'make' a better carb by using the best parts from both (or all ) of the carbs.

Bad idea.

The YF had several iterations in its life on the F-134, and there were several versions on other jeep engines.

Most of the inner parts will fit if interchanged, but they won't work properly. It took me several days of troubleshooting to purge a carb I had from the mish-mash of parts that a prior owner installed.

Best of luck to you on this. When you are done and have a good YF, you'll be glad you rebuilt it.

 

So you would suggest rebuilding it versus buying a new one?