Author Topic: Idf Carb Help (Read 2595 times)

Pipes · « **on:** March 13, 2008, 04:14:42 PM »

Finially! Chuck lives again, but I can't seem to get my Webber IDF40's to comply with my demands. Is there anyone out there confident in the tuning of these guys that can help me or perhaps perform the tuning with me for a fee? I'd really be thankful if you have your own stock of jets/venturies that you may be willing to utilize in the tuning.

Right now I am running a 2.1L Type4 motor with Porsche 914 heads. I can get it to Idle and rev great but under load driving its stumbling and backfiring like crazy.

Any takers?

Pipes · « **Reply #1 on:** March 18, 2008, 05:18:37 PM »

Just as an update, i found that two of my sparkplugs were bad. They only had a few hours on them when I last ran it about 2 years ago. I pulled them out and they still looked good, but in fact they are shorting! I've replaced them and the car runs quite well now. Still perfecting the tuning but otherwise its time to slap on some insurance!

Cameron · « **Reply #2 on:** March 19, 2008, 08:16:29 AM »

The best way to tune your carbs is to read the spark plugs, or install a Air Fuel Ratio (AFR) meter. Search the Air Speed Forum for info.
Make sure your ignition timing is set properly also.

Pipes · « **Reply #3 on:** March 20, 2008, 10:36:15 AM »

Thanks Cameron, I'll try pulling out the plugs and checking out thats going on in there.

As for the timing its a little tricking as it is a upright conversion I have no timing marks to go on. I used the \"straw\" meathod. Brought #1 to TDC on the compression stroke then marked off the crank pulley at the case split. Then fired it up and played with the timing back and forth until I found a good smooth running idle. Then reved it up some to see how it liked the advance.

I have put 3 days insurance on it now and am driving it. I've dialed the carbs in what seems to be pretty good smooth runing. the engine runs quite cool, but I have yet to hit the hwy.

The engine doesn't pop tick or back fire. So I'm thinking the timing is set pretty good. I do get a little hesitation on throttle application but I think thats the accellerator pumps that may need to be adjusted.