Carburetor

Marvel Schebler TSX-605 carburetor. It has no power jet but it has the threads for it. It has a power adj needle and a jet access plug in the bowl. Does the power adj needle meter the fuel into the nozzle or what ?

Check the online catalogs from Mike's Carb or McDonald's. Several other too and there are lots of M-S instruction sheets to download.

I've seen pictures and diagrams of the power jet, buy have never opened one up and found it!

Yes, the power adjust controls the flow of fuel through the main jet, which in turn flows through the nozzle and into the engine. All fuel passes through the main jet.

The upper adjustment is the idle mixture. Turning it in richens the mix as the needle regulates air bleed. The engine needs to be idling very slow, down around 400 RPM for this adjustment. Adjust it for the smoothest idle.

Then adjust the power jet. This adjustment controls fuel flow, so turning it in leans, out richens the mix. Start with it about 1 turn off (gently) fully seated. With the engine at idle, suddenly open the throttle and observe the response. If the engine revs without hesitation, turn the screw in 1/4 turn and try again. If it balks, back the screw out 1/4 turn. Keep repeating the test, each time letting the engine return to slow idle. When the mix is correct, the engine will take sudden throttle without hesitation. A single puff of black smoke is acceptable.

But before doing any carb adjustments, everything else must be right. The engine must be properly tuned, air cleaner serviced, valve lash set, thermostat working and up to temp, no vacuum leaks. An engine down on compression, or any other problems, will not run properly under even the best adjustments.

I ordered parts from McD and he said a 605 has no power jet. ?