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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Mon Oct 12, 2009 8:16 am Post subject: Carburetor adjustment |
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I am running a new 34 pct empi carb and it seems to run good with factory settings except for low rpm take offs.It will spit and sputter when taking off until the rpm's come up and then it smooths out. It also feels like it is holding back from power when cruising down the road at 55-60.I referred to my haines manual and took the adjustment screws all the way in and then backed them out 2 1/2 turns.With that being said which screw(bigger air screw)or(smaller gas screw) adjustment should be made and in what direction....in or out. Any suggestion will help and Thank you for your replys. |
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LeeVW Samba Member
Joined: June 14, 2006 Posts: 1016
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Posted: Mon Oct 12, 2009 8:33 am Post subject: |
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What type of distributor do you have? Does it have a vacuum line?
Have you tried adjusting the accelerator pump on the carb?
Lee |
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nybugguy Samba Member
Joined: September 21, 2008 Posts: 117 Location: Upstate New York
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Posted: Mon Oct 12, 2009 11:13 am Post subject: |
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I have a vacuum line but have no idea how to adjust the pump... |
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johncollins Samba Member
Joined: April 07, 2008 Posts: 84 Location: Dayton, Ohio
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LeeVW Samba Member
Joined: June 14, 2006 Posts: 1016
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Posted: Mon Oct 12, 2009 12:56 pm Post subject: |
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Could you post photos of the distributor, its vacuum line, and where the line is connected to the carb? Just want to make sure it's all hooked up properly. Also be sure any unused vacuum ports are plugged.
To adjust the accelerator pump, you first have to determine if you CAN adjust it. See if it has an adjustable bell crank like in this photo:
If so, loosen the bolt and turn the ball crank towards the + side, lock it down, go for a drive. If it gets better, you're on the right track. If it's worse, try going the opposite direction.
Lee |
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hottarod Samba Member
Joined: December 14, 2007 Posts: 507 Location: Jefferson
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Posted: Mon Oct 12, 2009 2:08 pm Post subject: |
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Check your pump shot. You should see a good strong squirt of gas. The acelerator pump channels are some of the first to get clogged up with something. The pump diaphram could also be cracked or weak and need replacing.
Turning the screws clockwise or in is lower/leaner and turning them out is the opposite. 2 1/2 is a starting point for adjusting your carb. Keep in mind that these screws control your engine up to around 2000 rpms. Set the fast idle screw first like all the helps say. Make sure your timing is set too. Adjust the big n little screws with the engine warmed up, no choke on and with the air cleaner on.
Once you have your idle/low speed screws initially set and the engine will wing up ok sitting still take it out and run it for a few miles. Don't exceed 2000 rpms. Pull over, stop and check 1 or 2 of your plugs(3 or 4 is best). Make sure they have good color. If not, adjust your fuel screw accordingly and recheck your idle rpms.
After that make sure you have a smooth transition from under 2000 rpms to over 2000 rpms. If it feels like its falling flat you may be too lean on the main jet.
Last edited by hottarod on Mon Oct 12, 2009 3:02 pm; edited 1 time in total |
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dazn9796 Samba Member
Joined: January 15, 2008 Posts: 176 Location: So Cal
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Posted: Mon Oct 12, 2009 2:23 pm Post subject: |
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Do yourself the biggest favor you will ever do. Throw that thing in the trash and get a 30/31 Pict carb. Easier to tune and no flat spots. I have had two or three of these carbs and nothing but trouble with all of them. Took them all off and put the 30/ 31 carb on and voila no more problems.
Dave _________________ The Older I get the smarter my dad was.
70 Safari Trail |
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