F 134 Running Rough

Sadler5 · Post by **Sadler5** » Tue Sep 08, 2009 7:21 pm

I just finished putting my F134 back together. Has good compression, oil pressure and new spark plugs and points. All gapped and engine is timed. It idles beautifully but when I give it a high idle and above it runs rough. Closing the choke doesn't help which may mean it is running rich. When I rev it up I do see a whif of black smoke. I rebuilt the Carter YF carburetor and it didn't really help. What is the nature of this that could possibly be wrong. I also have replaced the rotor cap. The distributor has a vacuum advance that seems to be working as it should. I have the hose hooked to the bottom port on the carburetor to the distributor vacuum. Thanks for any help you can offer.

MODIFIED · Post by **MODIFIED** » Tue Sep 08, 2009 9:19 pm

judging from the fact your vehicle possesses a "vacuum advance" you don't have a stock 24 volt mil. stock ignition? have you the "Ordinance manuals for proper trouble-shooting? i.e; TM9-8014 and TM9-8015-2 ?

Perform a vacuum test...

this is a good site to get general vacuum interpretations:

http://www.secondchancegarage.com/public/186.cfm

are you getting fuel to carb with ample pressure and volume?
have you replace the distributors condensor with your newly installed points ?

Post by **wesk** » Tue Sep 08, 2009 11:01 pm

I think it best you positively ID what accessories you have on your engine before we offer any suggestions for manuals or troubleshooting.

The YF carb is a civvy jeep unit. The M38 /M38A1/M170 did not come with vacuum advance. Most of the civvy jeeps did not either. The pickups and wagons with the L and F 134's had vacuum advance distributors and some Governor equipped jeeps had vacuum advance.

You describe a nice smooth idling jeep. This means the plugs and distributor points are most likely in good order. You say hi idle rougness and slight black smoke. With the civvy carb that could be float set to high, accelerator pump bad, bowl leaking into venturi, metering rod not correct, or even sticking float or needle seat.

Sadler5 · Post by **Sadler5** » Wed Sep 09, 2009 2:30 pm

Thanks for the help so far. I can add a little more information. I did replace the condenser (capacitor). Basically all the ignition including plug wires have been replaced with new. The carburetor also has a new kit installed with the accelerator pump. I noticed the metering rod does not go very far down in the orfice. It is like the accelerator pump does not go down far enough either. I don’t quite understand exactly how this should be set. Any help you can give here may lead me to my problem. This engine was a rebuild that was installed in an M38 A1 that I bought. I spec’d it out and rung it and have it running on my shop floor in an engine stand I fashioned. For cooling I have water running through the pump into the engine and out a drain. No radiator in other words.

MODIFIED · Post by **MODIFIED** » Wed Sep 09, 2009 11:31 pm

As Mr. K mentioned, we need more info and see some pics to properly assess your situation.

Sadler5 · Post by **Sadler5** » Thu Sep 10, 2009 4:10 pm

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Here you go. Thanks

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oreo3156 · Post by **oreo3156** » Sat Sep 12, 2009 8:54 am

Mine was doing the same thing, would start but run like crap. Had the carb off 50 times, tried everything. (im running 12 volt) Put a new coil on, and away she went.