Have a question about a briggs quantum carby (primer not choke). The engine is a XTS 50 from 2003. It’s in good condition and worked alright when I got it, but surged from cold. It was a bit better when warm. Anyway through one reason or another (partly because I infinitely prefer mowing with Victa 2 strokes) it sat for 3-5 months.
Went to start it last week as I thought I should, but I was too late – clogged carby. I will be installing a fuel tap shortly – they should come from the factory with one.
Ripped it apart and cleaned it out, and ran, but still surged badly when cold and somewhat when hot. Tore it down again and gave it an extra thorough clean, with only slight improvements.
The plug electrode is white (and always was white), which of course means its lean – also explains the surging. Checked the o rings, and cleaned all mating surfaces – no leaks.
My query is, where are the hidden mixture adjustment screws on this carby. They must be there somewhere.
There is a ball bearing plug on the carby (as shown in the picture), I am thinking of drilling a small indent above the ball bearing, so I can lever it out with a screw driver.
I am guessing there will be an idle mixture screw – but I don’t want to just open up a fuel passage.
