Carburetor Setting or Startup Procedure

Sat Apr 05, 2014 3:33 pm

I've just completed the rebuild on my cub and almost got it started. I was so excited that it kicked off and ran like it should. Let me start by saying that I purchased a original style IH carb off of E-Bay (seller said it was off of a running cub) to replace the Zenith carb that someone had put on it years ago.
I choked it a little while starting and it kicked off really good. It ran for about a minute or so before shutting off. I tried multiple times with and with out choke but it would never really kick off and run again. I did notice that I had gas dripping out of the bottom of carburetor where the air cleaner connects. My first thought was that it was flooding. I did not change the set screw on the carb since it came from a "running" cub.
Does anyone have advice on setting the carb and getting everything set up so that it will start and run as it should? A failsafe startup procedure would be great.
Thanks Paul

Re: Carburetor Setting or Startup Procedure

Sat Apr 05, 2014 4:30 pm

If you did nothing to the carb, chances are that some accumulated crud was broken loose during shipment and is now lodged in the main metering jet.
First -- remove the pipe plug in the bottom of the bowl and let a cup or two of gas run in to a clean clear container. Then check for contaminants in the bottom of the container. I'm confident that you will probably find some. Replace the plug.
Second -- With the gas shut of at the sediment bowl, remove the main metering jet from the side of the carb (brass hex head near the very bottom of the carb). Examine the holes for foreign material and use a small soft wire (a piece of copper telephone wire works great) to clear the obstruction. Spray the jet with carb cleaner being careful to protect your eyes. Repeat the process and blow the jet out with air. Before reinstalling the jet flush the carb with gas, catching the outflow in that clean clear container. Check the container for contaminants, if clean. Reinstall the jet.
Third -- Turn on the gas and fire it up.

If you are unable to get clear gas to come out of the carb, it is time for disassembly and a thorough cleaning of the carb.

Good Luck.

Re: Carburetor Setting or Startup Procedure

Sat Apr 05, 2014 5:33 pm

Thanks for advice Bill. I will give your suggestions a try. What about the jet screw at the top of the Carb? How should it be set?

Re: Carburetor Setting or Startup Procedure

Sat Apr 05, 2014 5:36 pm

For now, I would leave the screw where it is and see how it preforms after following Bill's advice. Once the Cub is running it can be determined what to do next.

Re: Carburetor Setting or Startup Procedure

Mon Apr 28, 2014 10:11 pm

Okay, quick question.. It's late and I can't seem to find where to create a new post/question about a different topic. I have another question to post but can't find the link like I have in the past.Hopefully one of you guys will see this and help me out.

Re: Carburetor Setting or Startup Procedure

Mon Apr 28, 2014 10:16 pm

At the top of the Cub Forum you will see a button that says "New Topic". Click on it to start a new topic.