Hey guys got a 35 cig. Twin blown 540s. Carb problems.
01-25-2019, 05:50 AM
#11
Registered
I've run several blower setups, like some said before, TIMING, I would lock the advance, run 28, with the low compression of the blower motors starting should not be a issue and the more base will help the idle.
01-25-2019, 09:27 AM
#12
Registered
Check the position of your throttle plates as well. If you are uncovering the idle circuit slot you will need to drill a small hole in them to get more air. I have a really big cam and I do a lot of river cruising, spent a lot of time experimenting with timing and carb adjustments. I'm running an MSD ignition and played with different springs and bushings and finally locked the distributor. I also made sure that primary and secondary throttle plates were aligned in the idle circuit slot. I also set the throttle plates so they were 60/40 to the primary. With a real lumpy cam using a vacuum gauge is tuff, I adjusted the idles circuit based on max rpm with a digital gauge. My idle speed in neutral is 1000rpm and 700rpm in gear, with my cam that's the best I can do. Out of everything I did, the timing was the biggest deal. With a 10:1 motor and 35 degrees of timing, I get the motor spinning before I hit the gas to start it. It does start fast set up this way. I once ran the batteries down to the point it would only crank one compression stroke. I pumped the throttles lightly to give it a little gas and quickly hit the key and let go so it would return to run before it completed the compression cycle and it started. It's not like an EFI motor but it runs so good now I wouldn't switch. I can run over an hour down the river and no gas smell no soot, it's the cleanest running motor I've ever had. Have patience, I spent several seasons tweaking it until I got it perfect.
Platinum Member
01-26-2019, 02:49 PM
#14
Check the position of your throttle plates as well. If you are uncovering the idle circuit slot you will need to drill a small hole in them to get more air. I have a really big cam and I do a lot of river cruising, spent a lot of time experimenting with timing and carb adjustments. I'm running an MSD ignition and played with different springs and bushings and finally locked the distributor. I also made sure that primary and secondary throttle plates were aligned in the idle circuit slot. I also set the throttle plates so they were 60/40 to the primary. With a real lumpy cam using a vacuum gauge is tuff, I adjusted the idles circuit based on max rpm with a digital gauge. My idle speed in neutral is 1000rpm and 700rpm in gear, with my cam that's the best I can do. Out of everything I did, the timing was the biggest deal. With a 10:1 motor and 35 degrees of timing, I get the motor spinning before I hit the gas to start it. It does start fast set up this way. I once ran the batteries down to the point it would only crank one compression stroke. I pumped the throttles lightly to give it a little gas and quickly hit the key and let go so it would return to run before it completed the compression cycle and it started. It's not like an EFI motor but it runs so good now I wouldn't switch. I can run over an hour down the river and no gas smell no soot, it's the cleanest running motor I've ever had. Have patience, I spent several seasons tweaking it until I got it perfect.
01-26-2019, 05:52 PM
#15
Registered
I had the same problem last year, tried ignition and other stuff, I end up stepping back. Set the ignition back to stock 10* with stunt in, I then set the primary throttle plates where they should be, changed the secondary throttle plate adjuster screw so it was easy to adjust.
between adjusting the secondary throttle plate and idle mixture screw I could idle at 850 out of gear and 750 in gear all day long. Took around three hours to find the sweet spot
between adjusting the secondary throttle plate and idle mixture screw I could idle at 850 out of gear and 750 in gear all day long. Took around three hours to find the sweet spot
