Posted by Sherman in Idaho [72.47.153.61] on Monday, April 20, 2015 at 21:40:48 :
Just thought I'd report that I just did that carb conversion I'd talked about last fall and it works like a champ. I used the synchronous rather than progressive 2-barrel because the trolley bus application works the engine pretty hard. The conversion was straightforward except for making a new throttle linkage, which I expected. I got the electric choke version so the drivers wouldn't have to learn to use a manual choke. The bus starts easily now, cold or hot, and accelerates smoothly with no missing, sputtering, or dead spots. The Mine Tour opens the first of May so I'll be curious to hear how the drivers like it but I would definitely recommend the weber as an improvement or replacement for the stock carb.
The kit came with a throttle linkage adapter that I couldn't use but everything else was fine. It does have some quirks. The choke seems to take too long to open and it re-closes too quickly after shut-down, but that might just be the way those primitive heater-spring electric chokes are. I suspect fuel economy will suffer. Hopefully the plugs won't get fouled. Also, even though I can slow it down to a pretty slow idle (didn't put a tach on it), screwing the idle mixtures screws (one for each barrel) all the way in doesn't stall the engine. It's like it's still getting some fuel somewhere. It's rare that I've worked on a carb/engine where the idle mixture screw really did all that it's supposed to do, though, so I just set them back to 1-1/2 turns and left them there. I didn't check it with my vacuum gauge but the vacuum gauge on the dash shows about 20" at idle. Seems a little low, but the engine has plenty of miles on it. All in all, I think it will be good.
Follow Ups: