Post by rowdy235 on May 8, 2018 20:23:42 GMT -5
Hey All,
As some of you may know I picked up a ST-145 string trimmer about a year ago. It didn't take me long to get it running and I've been getting some good use out of it.
However, this weekend I had an issue. After about a tank and a half of cutting, the machine started cutting out at high revs. It would idle all day long but if you tried to give it gas it would bog and die. The only way I could get it revved up was to put the choke on at the same time I pulled the throttle trigger, and then slowly open the choke as the revs came up. Once it was up near WOT it would be okay but after a couple minutes it would start cutting out and I was right back to square one.
Immediately I suspected a carb issue, so I checked online. It looks like carb kits and carbs are NLA through the usual channels, albeit I didn't look all that hard.
I knew it was a risk but I pulled the carb apart without a kit. I pulled off the stupid plastic covers on the high and low jets and backed them completely out. Gave it all a good dose of seafoam and blew some air threw the passages and put it back together. To my relief no leaks once back together! I set each screw 1 turn out to start and got it started back up. Tuned the carb and I think I'm about 1 1/2 out on the low and 3/4 out on the high.
I went and cut for pry about 15-20 minutes and all seemed good, but won't really know until I can run it longer. I did have a question though- how would you guys tune the high speed on the carb? Usually on a saw I tune it to where it 4 cycles at WOT w/ no load but clears up when dropped into wood. It's a little harder to do that with a string trimmer since the load is more dynamic. I've got it now to where it 4 cycles at WOT but will clear up when you put it into grass. Trouble is as the string wears down it gets less and less of a load so eventually it doesn't clear up when cutting, but I've always thought it better to run a little rich vs a little lean. Thoughts?
As some of you may know I picked up a ST-145 string trimmer about a year ago. It didn't take me long to get it running and I've been getting some good use out of it.
However, this weekend I had an issue. After about a tank and a half of cutting, the machine started cutting out at high revs. It would idle all day long but if you tried to give it gas it would bog and die. The only way I could get it revved up was to put the choke on at the same time I pulled the throttle trigger, and then slowly open the choke as the revs came up. Once it was up near WOT it would be okay but after a couple minutes it would start cutting out and I was right back to square one.
Immediately I suspected a carb issue, so I checked online. It looks like carb kits and carbs are NLA through the usual channels, albeit I didn't look all that hard.
I knew it was a risk but I pulled the carb apart without a kit. I pulled off the stupid plastic covers on the high and low jets and backed them completely out. Gave it all a good dose of seafoam and blew some air threw the passages and put it back together. To my relief no leaks once back together! I set each screw 1 turn out to start and got it started back up. Tuned the carb and I think I'm about 1 1/2 out on the low and 3/4 out on the high.
I went and cut for pry about 15-20 minutes and all seemed good, but won't really know until I can run it longer. I did have a question though- how would you guys tune the high speed on the carb? Usually on a saw I tune it to where it 4 cycles at WOT w/ no load but clears up when dropped into wood. It's a little harder to do that with a string trimmer since the load is more dynamic. I've got it now to where it 4 cycles at WOT but will clear up when you put it into grass. Trouble is as the string wears down it gets less and less of a load so eventually it doesn't clear up when cutting, but I've always thought it better to run a little rich vs a little lean. Thoughts?
I may still have to tinker with the low speed, at times it was not wanting to idle, probably made a little worse by the lack of a clutch (string always turning)