| Lack of power at speed [message #89337] |
Sun, 20 June 2010 17:32  |
docsdad
Messages: 32
Registered: May 2008
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I fired up the Mother Ship a few days ago with the intention of going to my son's in Illinois. Temp was 100 degrees and just a few miles down the interstate, I experienced what I assumed was the dreaded "vapor lock" Struggled to the next exit and turned around for home. It missed, sputtered and actually died a couple times, I pulled over and it would start back up and I struggled home on a local 2 lane at 35 miles per hour. When I tried to step on gas to increase speed, It was like I turned off the key and it would slow down and sputter along. Pumping the foot feed seemed to help but for the last 3 miles just running at 35 to 45 it seemed to run ok if I did not push it.
When I got home, I decided to install new electronic module as the symptoms seemed to point me in this direction. Next day, cooler weather, well cloudy and in the 90's. Took the motor home out, It run fine on two lane road 45 to 55 if I did not push accelerator down very strongly. If I floor it it does not speed up just seems to slow down, like it is not getting any gas. But if not pushed hard, it seems to run ok.
I am thinking the secondaries are not functioning. Need you collective brain power. I have had the carb off three times now trying to find something wrong. The only thing that I find is as follows. The baffle in the secondary throttle bore, is missing, has always been this way since I have owned the rig. The upper plates on the secondary bores seem to have a bit of a sticking condition when they go to the fully closed position. I am not an expert on carbs, but I do not understand exactly how the secondaries are supposed to work. It seems on my carb the upper plates on the secondary control the secondary jets through cam action, but I do not understand what causes the secondaries to open other than the flow of air when the throttle plate opens as there seems to be not connection between the upper plates and the throttle plates. .
I am about ready to change over to Fuel injection, but I need to know that I am not overlooking something simple.
Your thoughts and advice would be appreciated.
Jim Thompson
Georgia
75 Avion that used to run like a top.
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