PushnFords
ArboristSite Lurker
First of all...I found a great link to a site with videos showing someone tuning a carb complete with .wav files. I had it open & my computer crashed...can't find it again. Links would be appreciated if you know where to find them.
I put a new carb on an MS250 after it had sat and varnished the old one up. I tuned it by ear: In on the L jet until it slowed, out until it slowed, then split the difference. Next on the H jet in until it started to stumble, out until it blubbered, and then back in just a touch so it was on the edge of blubbering & running smooth. That's how I usually do them and they have started and ran good. But since I had access to a service manual I decided to try it "by the book" (*note...used the MS192T service manual instructions...seemed to be very similar to others I'd looked up). So...I grabbed my tach and set the idle at 3500 then adjusted the L screw to highest rpm (about where it was already). Set the idle down to 3000 then checked max rpm & I had 14,600 so I richened the H needle until I got down to 13,500. Went back & checked the L adjustment, then the H again, then did both again until no adjustment needed. It ran & cut good and seemed to be cutting very nice...but not it is a PITA to start. It acts & smells like it is way too rich...the H screw is 1 3/4 turns out. Am I reading something in the manual wrong or do I just need to go back to doing it by ear?
I put a new carb on an MS250 after it had sat and varnished the old one up. I tuned it by ear: In on the L jet until it slowed, out until it slowed, then split the difference. Next on the H jet in until it started to stumble, out until it blubbered, and then back in just a touch so it was on the edge of blubbering & running smooth. That's how I usually do them and they have started and ran good. But since I had access to a service manual I decided to try it "by the book" (*note...used the MS192T service manual instructions...seemed to be very similar to others I'd looked up). So...I grabbed my tach and set the idle at 3500 then adjusted the L screw to highest rpm (about where it was already). Set the idle down to 3000 then checked max rpm & I had 14,600 so I richened the H needle until I got down to 13,500. Went back & checked the L adjustment, then the H again, then did both again until no adjustment needed. It ran & cut good and seemed to be cutting very nice...but not it is a PITA to start. It acts & smells like it is way too rich...the H screw is 1 3/4 turns out. Am I reading something in the manual wrong or do I just need to go back to doing it by ear?
