mehas240z Posted October 13, 2010 Share Posted October 13, 2010 Hey guys, I did a search, couldn't find the answer to my question. Here is my setup and my issues. I have the dual weber dgv setup on my 280 engine. However the kit I bought was the 240/260 kit. (I hope this isn't my issue and can be made to work with my 280 engine) Car runs and my mechanic said it runs a little rich, he would have switched the jets but they were on backorder, he said he ordered them but hasn't called me in months. (Forget him) So the car no runs eh...at best. It idles fine, a little lumpy and might be a timing issue. When I roll on the gas it revs fine. If I stomp on the gas, the rpms drop and it sounds like it is drowning...it will either stall, or it will rev very roughly up through the range, after the rpm drop, and make a few popping sounds. I went through the list that came with the carbs to narrow down issues regarding my situation. I have no fuel issues, that's as far as I got. Where do I go from here? Ignition? I would think that it would run slightly lean if I was using jets for a 240/260 on a 280...I guess I am wrong? Would a video help? Thank You, -Brian! Quote Link to comment Share on other sites More sharing options...
The Crusher Posted October 15, 2010 Share Posted October 15, 2010 I run dual dgv webbers on my 240z. It has a 280 motor and runs great. Motor size not a problem. With webbers they need to be tuned and ajusted. They will work and maybe even idle OK right out of the box, but you must tune them. Lots of info on how to do this all over the web. It sounds like maybe your idle circut might need some adjustment to start with. You may or may not need to re-jet, but you wont know until you get the idle circut right. You will also need some syncro meters to make them work together as one, this is very important. Doing it by eye is not good enough. Also, you should be able to get the jets from alot of places, hard to belive they would be on back order. Anyway, good luck. Richard B. Quote Link to comment Share on other sites More sharing options...
mehas240z Posted October 18, 2010 Author Share Posted October 18, 2010 Hey there everybody, I followed the directions for adjusting the idle screws and mixture screws and here are my results. I bottomed out the the mixture screws and the engine got to a very good idle compared to how my mechanic had left it. The idle did not roughen up until I hit about 2 turns out. I set the idle speed screw off of that. I noticed though that on these settings without adjusting the idle it was backfiring. It seemed that when I backed the screw out it got worse but only after ~2.25 turns on each carb. I just bottomed them out again and will focus more this weekend as it is getting cold and dark out. I was able to roll on the accelerator more heavily but I am still not able to stomp on it as if I was getting onto a highway or something. What does this tell me? I had a problem determining my results as the guide I was using only covered rough idles up to 2 turns and I didn't experience any of this. Thanks guys, -Brian! Quote Link to comment Share on other sites More sharing options...
mistah mofro Posted October 18, 2010 Share Posted October 18, 2010 where are these mixture screws? I dont have the information to find out whats what on my DGV webers, thanks. Sorry to thread jack btw Quote Link to comment Share on other sites More sharing options...
mehas240z Posted October 18, 2010 Author Share Posted October 18, 2010 where are these mixture screws? I dont have the information to find out whats what on my DGV webers, thanks. Sorry to thread jack btw the mixture screw is the one that has a spring between it and it's seat on the side of the carb that is facing the exhaust manifold. Kind of angled towards the firewall side. The idle adj. screw is the gold on on the firewall side of the carb. It is gold, on mine at least. Quote Link to comment Share on other sites More sharing options...
The Crusher Posted October 18, 2010 Share Posted October 18, 2010 http://www.carburetion.com/weber/adjust.htm This is a good reference for adjusting your webbers. I think you were too far out on the mixture screws, they need to be between 1 1/2 to no more than 2 turns out and give you a good idle. (If a good idle can not be had then you are too rich or too lean. Less then 1 1/2 out for a good idle and your too rich. More then 2 turns out and you are lean.) Then the idle screw can be ajusted and can be no more than 2 turns in. If more than 2 turns in are needed for a good idle than you are lean. By opening the idle screw more than 2 turns, you are creating a rich condition. I hope this helps. Quote Link to comment Share on other sites More sharing options...
mehas240z Posted October 19, 2010 Author Share Posted October 19, 2010 Oh man then I must be rather super rich because the idle got better when the screw was seated and up until 2 turns out it was fine. Thanks for your help guys, I'll keep you posted. Quote Link to comment Share on other sites More sharing options...
The Crusher Posted October 19, 2010 Share Posted October 19, 2010 mehas240z- You are just looking for the best idle and it is best to be between 1 to 2 turns out on the mixture screws. Even better at 1 1/2 to 2 turns out. You would rather be a little rich than to be to lean. As you turn out the screws and it gets rough, stop,and turn them back in until it smooths out. You want to be right at the edge of it. Again- you DON'T want to be to LEAN. Any thing under 1 turn out and you need to re-jet. Good luck. p.s. Re-jet in small steps. Very important. One size at a time. Quote Link to comment Share on other sites More sharing options...
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