So I have been chasing this for a week and a half. I have 71 360 with a 2150 carb and auto trans. The truck starts idles as smooth as a sewing machine and runs down the road great, but just of idle it bogs fairly bad. I have put hei distributor and wires with plugs gaped at 40. Tuck is pulling 17 on the intake vacuum at idle which is 850 in park. Timing is set at 12 degrees btdc. I have tried both the motor craft carb which is rebuilt and a cheap 2150 of amazon “China” carb, the cheap carb seems to do a little better. I also have tried the accelerator pump in all settings with no noticeable change other than the bottom hole which causes high idle, idle mixture screws 2.5 turns. Timing I have tried 8-14 btdc. I’m also running a manual choke and have checked for vacuum leaks. I can pull out on the highway on level ground after it has warmed up, and put it to the mat and it really doesn’t hesitate much at all. Where I work is down mountain dirt road and when I come out of there I’m just in that flat spot the whole way. Not really wanting to dump money in to the gas side of things because I have a 96 Cummins I plan on putting in at some point. Advice is very appreciated.
Your issues may be with the 2150 vs a 2100. The 2150 had designed in emissions related circuits that specifically prevents gas from flowing through the carburetor's idle circuit when decelerating. https://itstillruns.com/2100-vs-2150-mo ... 28562.html
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
Thanks for the link and the response. Could it be that easy? I didn’t realize that the 2150 came into play till 73, I just replaced what was on it when I got the truck. The truck does run perfect at idle and anything half throttle and above even at a load. It’s just that spot off idle and under load it falls on its face.
Only other thing I can think of is fuel/air mixture. My 302 with a 2100 consistently tuned at 20-21 vacuum at 700 rpm idle, and that's with over 200,000 miles on the original engine and weakened compression at the cylinders.
Randy
1970 F100 Sport Custom Limited LWB, 302cid, 3 on the tree. NO A/C, NO P/S, NO P/B. Currently in 1000 pcs while rebuilding. Project thread: http://www.fordification.com/forum/view ... 22&t=59995 Plan: 351w, C4, LSD, pwr front disc, p/s, a/c, bucket seats, new interior and paint.
1987 F-150 XLT Lariat, 5.0/C6 auto.
So I have been chasing this for a week and a half. I have 71 360 with a 2150 carb and auto trans. The truck starts idles as smooth as a sewing machine and runs down the road great, but just of idle it bogs fairly bad. I have put hei distributor and wires with plugs gaped at 40. Tuck is pulling 17 on the intake vacuum at idle which is 850 in park. Timing is set at 12 degrees btdc. I have tried both the motor craft carb which is rebuilt and a cheap 2150 of amazon “China” carb, the cheap carb seems to do a little better. I also have tried the accelerator pump in all settings with no noticeable change other than the bottom hole which causes high idle, idle mixture screws 2.5 turns. Timing I have tried 8-14 btdc. I’m also running a manual choke and have checked for vacuum leaks. I can pull out on the highway on level ground after it has warmed up, and put it to the mat and it really doesn’t hesitate much at all. Where I work is down mountain dirt road and when I come out of there I’m just in that flat spot the whole way. Not really wanting to dump money in to the gas side of things because I have a 96 Cummins I plan on putting in at some point. Advice is very appreciated.
