I have a Toro 524 with Tecumseh engine, model 38040 8 0000640. I am rebuilding the carb and would like to know what are basic settings for idle and hi/low speed screws?

Here's a link on your timing problem. How to Set Timing on Tecumseh 6 5 HP Lawn Mower herte's another video to see. HOW TO Replace the Flywheel KEY on your Lawnmower with Tecumseh Engine fix...

If the carb is still intact, you may just want to rebuild it. Parts are easy to find and inexpensive.

This blower looks to the Tecumseh engines so try looking in the L head service manual for H 50-H80 engines under ignition timing.

http://www.mymowerparts.com/pdf/Tecumseh-Service-and-Repair-Manuals/TECUMSEH-SERVICE--REPAIR-MANUAL-3HP-TO-11HP-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf

"Most likely you'll have to remove the bowl nut, under the carb's bowl. You'll most likely find varnish in the jet, or maybe water. These are some typical jets, Tecumseh. Briggs, similar" (baymee LehighValleyPA, 2009).

I'm going to try this tomorrow myself!

The carburetor may need to be serviced. You need to find a parts shop that handles Tecumseh parts. You will most likely need a rebuild kit for the carburetor. The carburetor part number is 640303. The rebuild kit is 632809. The Tecumseh engine company shut its' doors 3 years ago. Finding parts is becoming harder and harder. I've heard that someone has bought Tecumseh over the winter but it is unknown when the new parts will hit the market. Best of luck to you.

PartsTreeRepairClinic may have a video

what exactly do you want to know? Carb. mixture settings are as follows: L-head engines

Tecumseh carbs.........mainscrew 1 3/4 turns idle screw 1 1/4 turns
Walboro carbs........... mainscrew 1 1/2 turns idle screw 1 1/4 turns

L-head and OHV heavy duty engines 1 turns for both

coil is breaking down under heat