My GT-150 is showing classic signs of running lean. anyone know which screws are the ones that can helpme richen the fuel mixture? Thanks

If you're talking about on the carb, everything is fixed, so there are no mixture adjustments you can make to them. What you will need to do is a completer link and sinc, but before doing this, make sure the cam roller is still complete. Usually the outer shell comes breaks appart, leaving nothing but the center black piece. IF it approx 3/8" in diameter and has a clear looking section over a black center, then it's probably good. If it's black and only about a 1/4" in diameter, you need a new one before you even start doing the linc and sinc. If in doubt, buy a new one and replace it, they are cheap and usually need replacing anyway.

A full linc and sinc is not easy, and you have to pay attention to every detail, check and double check after doing it. You may have to go through it three or four times to get it exact. Getting all three carbs sinc'd exactly and is required, it's not overly difficult but you have to be sure all three respond exactly, or it will not run it's best.

From there, you have to make sure you have good fuel pressure, clean carbs and a whole lot of other stuff.

If you're talking about on the carb, everything is fixed, so there are no mixture adjustments you can make to them. What you will need to do is a completer link and sinc, but before doing this, make sure the cam roller is still complete. Usually the outer shell comes breaks appart, leaving nothing but the center black piece. IF it approx 3/8" in diameter and has a clear looking section over a black center, then it's probably good. If it's black and only about a 1/4" in diameter, you need a new one before you even start doing the linc and sinc. If in doubt, buy a new one and replace it, they are cheap and usually need replacing anyway.

A full linc and sinc is not easy, and you have to pay attention to every detail, check and double check after doing it. You may have to go through it three or four times to get it exact. Getting all three carbs sinc'd exactly and is required, it's not overly difficult but you have to be sure all three respond exactly, or it will not run it's best.

From there, you have to make sure you have good fuel pressure, clean carbs and a whole lot of other stuff.

X2 !!

Nice post Way2slow, I have seen the primer bulbs get old and start to crack and allow air to be sucked into the fuel system as well,especially around the quick connect "o" ring at the lower engine base, double check your fuel lines and your complete fuel system for any needed repairs also.

Good luck and be safe!!!