mandelbrotx Posted February 11, 2009 Share Posted February 11, 2009 (edited) After a week of searches here on the forums I haven't been able to find the reason for my idle issues. I think I have my timing in the ball park, but its hard to pin down because of what I think is an issue with my carb. I can't get the 79 brat to idle any lower than 1100rpm or it will slowly die, and it seems to do best at about 1500. It will slowly loose rpm for a minute or so and then do one of two things; stall out unless I give it some gas or put my finger over half of the choke, OR it will drop to 900 or so and then start to race upto 2500 and will stay there until I push the throttle lever down. Then it will repeat that and the warmer it gets, the worse it gets. Also there is a big sucking sound coming from the first barrel when it starts to rev up on its own. Also, it floods VERY easy. I'm going to replace all the vacuum tubes in the morning in hopes that helps. Anyone have any ideas other than get a webber? I need new tires and shocks before I get a new carb. Edited February 11, 2009 by mandelbrotx Solved Quote Link to comment Share on other sites More sharing options...
ihscout54 Posted February 11, 2009 Share Posted February 11, 2009 The flooding is most likely your problem. The sucking sound is just the air rushing through the throttle bore and might be enhanced by the extra fuel being slurped down. Your float or needle and seat is in need of inspection. It sounds like its time for a rebuild. Quote Link to comment Share on other sites More sharing options...
Frank B Posted February 11, 2009 Share Posted February 11, 2009 +1 for the rebuild. get the kit from Subaru if it's still available. The kits I've used from parts stores are good, but the rubber parts don't seem to last. the kit will have the choke and needle setting listed, make sure you adjust them to spec. Also, pay attention to the base gasket, you want to clean the base of the carb and the manifold perfectly. A vacuum leak here will cause a bunch of problems. There is a vertical roll pin on the front of the carb, just above the base, behind it is a horizontal hole behind it. Drive out that pin once the carb is off, the idle mixture adjustment screw is in that hole. Carefully turn the screw in counting the turns untill it stops, but do not tighten it. remove it and spray carb cleaner in the hole during your rebuild/cleaning. Afterwards do a search or ask about adjusting that screw. start with the same position it was in. Quote Link to comment Share on other sites More sharing options...
mandelbrotx Posted February 11, 2009 Author Share Posted February 11, 2009 I did the rebuild a few days ago, top half only because other than the accelerator pump being dead (the ball was broken and lodged in the port) and the float level every thing was working well. I did find the problem with flooding. When I first got the car, the contacts in the fuse box were covered in oxidations and not allowing current to flow to the fuel pump. Rookie mistake, I thought the issue was in the wiring, so I ran the fuel pump off a switch in the cab. A lack of lights and buzzers and some emery cloth later the fuse box was fixed. But the pump was still on the switch, and was pushing fuel into the carb after the engine stalled, flooding it. I just wired it back into the voltage regulator and problem solved. The other problem was solved by removing all of the California emissions garbage that was bad. Runs like a Scalded rump roast ape now. Quote Link to comment Share on other sites More sharing options...
Greenley Posted February 11, 2009 Share Posted February 11, 2009 The other problem was solved by removing all of the California emissions garbage that was bad. Can you go into some detail on what you removed? Quote Link to comment Share on other sites More sharing options...
bheinen74 Posted February 11, 2009 Share Posted February 11, 2009 Can you go into some detail on what you removed? yeah no kidding, happens my BRAT came from CA and i won't need the emission crap. want to make it run like a scalded ape here as well. Quote Link to comment Share on other sites More sharing options...
mandelbrotx Posted February 11, 2009 Author Share Posted February 11, 2009 Yanked the EGR valve, anti back fire valve, and the evaporative can. Also shortened all the vacuum lines I could. I think there are some other hoses that I can plug and move, but need to look over the diagram again. I did this to my S-10 last year and got a lot more response after, however my mpg dropped from 17 to 12. I also did a full tune up, timing, valve travel and some good plugs. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.