by veefre Mon Apr 07, 2014 6:51 pmWell, the '67 wasn't running so well, so I engaged in a series of carb fixes. Probably already posted about the problem with the throttle linkage: at some time in the past, someone installed a master brake cylinder that blocks the full return of the gas pedal. It was beyond the ability of the various screw adjustments in the linkages to fix. Finally I took apart the lever/pivot at the gas pedal, stuck it in a shop vice, and used a 1/2" piece of steel pipe to twist the linkage in the direction of a higher pedal at idle. Took a few tries: twist, test, twist, test, etc. Finally the pedal height is such that it can get full throttle.
The other problem was the accelerator pump. I had rebuilt the carb back in 2008 when I got the van, and thought that was all adjusted properly. But this past year the van started having very poor power, barely able to get up to 60 on the freeway. And that's with a V8. A little inspection showed that the pushrod in the accelerator pump had popped out of the pump cup housing, and was preventing the throttle from opening more than about 1/4 of the way. I stuck it back together and it was ok for a while, but then it popped out again. I figured the delay spring was strong enough to cause it to pop, so I both crimped (as best I could) the plastic housing around the push rod and put in a shorter spring (1.5" vs 2.0") that I found at the local hardware store. That seemed to fix the problem, but I figured the darn pump would separate again and cause problems.
I so got online and ordered a new carb rebuild kit from Mike's Carburetors, along with a spare accelerator pump. The spare pump came fitted with a spring, which was a plus.
When I got the new kit I basically just used the new pump and a new gasket. The rest of the carb was still clean and in good shape/adjustment. Then I started noticing a flat spot on acceleration. Checked the float height, seemed ok, but then I realized I'd been adjusting the float height w/o the gasket in place. Readjusted and the flat spot was worse. Checked the float height again and it seemed off, so changed the adjustment point. While I was at it, I decided to use the "spare" accelerator pump that I had ordered separately. This one was a little different in that the push rod is maybe 1/8" shorter than the ones that came with the rebuild kits. While I was doing that, I checked the previous two accelerator pumps - the one that came with the car, and the one that was in the 2008 rebuild kit - and I noticed that when I tested them, they fit too loose in the pump well and didn't squirt worth a damn. The pumps in the latest kit, along with the spare, have expansion springs inside the pump cups, and these squirted just fine. While I was at it, I checked and adjusted the accelerator pump linkage to spec.
Anyway, to make a long story a little less long, the last pump (shorter rod) and the latest float height adjustments seemed to have done the trick. No flat spot, plenty of oomph.
One of the challenges here is figuring out just what kind of carb this one is. The little metal tag with the proper carb nunmber is long gone. The number cast in the bottom of the float bowl is a casting number, not a carb number that would indicate things like machining done after casting.
Luckily since 2008 I had procured a set of service/chassis manuals for this van. At the back I could narrow down the carb number to one of two possibilities for a 283 motor without an air pump, without overdrive, with manual trans, and no governor. The basic carb is a Rochester "2 Jet". If anyone is interested I'll post the carb number(s) along with the kit number and the part number for the accelerator pump that seems to work ok.
PS-After all these adjustments the van seems to idler smoother and cleaner, as well.
The other problem was the accelerator pump. I had rebuilt the carb back in 2008 when I got the van, and thought that was all adjusted properly. But this past year the van started having very poor power, barely able to get up to 60 on the freeway. And that's with a V8. A little inspection showed that the pushrod in the accelerator pump had popped out of the pump cup housing, and was preventing the throttle from opening more than about 1/4 of the way. I stuck it back together and it was ok for a while, but then it popped out again. I figured the delay spring was strong enough to cause it to pop, so I both crimped (as best I could) the plastic housing around the push rod and put in a shorter spring (1.5" vs 2.0") that I found at the local hardware store. That seemed to fix the problem, but I figured the darn pump would separate again and cause problems.
I so got online and ordered a new carb rebuild kit from Mike's Carburetors, along with a spare accelerator pump. The spare pump came fitted with a spring, which was a plus.
When I got the new kit I basically just used the new pump and a new gasket. The rest of the carb was still clean and in good shape/adjustment. Then I started noticing a flat spot on acceleration. Checked the float height, seemed ok, but then I realized I'd been adjusting the float height w/o the gasket in place. Readjusted and the flat spot was worse. Checked the float height again and it seemed off, so changed the adjustment point. While I was at it, I decided to use the "spare" accelerator pump that I had ordered separately. This one was a little different in that the push rod is maybe 1/8" shorter than the ones that came with the rebuild kits. While I was doing that, I checked the previous two accelerator pumps - the one that came with the car, and the one that was in the 2008 rebuild kit - and I noticed that when I tested them, they fit too loose in the pump well and didn't squirt worth a damn. The pumps in the latest kit, along with the spare, have expansion springs inside the pump cups, and these squirted just fine. While I was at it, I checked and adjusted the accelerator pump linkage to spec.
Anyway, to make a long story a little less long, the last pump (shorter rod) and the latest float height adjustments seemed to have done the trick. No flat spot, plenty of oomph.
One of the challenges here is figuring out just what kind of carb this one is. The little metal tag with the proper carb nunmber is long gone. The number cast in the bottom of the float bowl is a casting number, not a carb number that would indicate things like machining done after casting.
Luckily since 2008 I had procured a set of service/chassis manuals for this van. At the back I could narrow down the carb number to one of two possibilities for a 283 motor without an air pump, without overdrive, with manual trans, and no governor. The basic carb is a Rochester "2 Jet". If anyone is interested I'll post the carb number(s) along with the kit number and the part number for the accelerator pump that seems to work ok.
PS-After all these adjustments the van seems to idler smoother and cleaner, as well.
