Toro 521 carb adjustment

Parkmower

Parkmower

Well-Known Member
I have a toro 521
M#:38052
S :5903376
I put a new carb kit in it and does run better.
But don't know the carb adjustments. I just played with them til it ran good.
One screw on side, mixture
And one up thru main jet bolt on bowl.
 
Did your carb kit have a new bowl nut/jet? Or did you use the old one? Usually you set the screws @ 1- 1 1/2 turns out to start.
 
Fish said:
Did your carb kit have a new bowl nut/jet? Or did you use the old one? Usually you set the screws @ 1- 1 1/2 turns out to start.
Click to expand...

Yes new bolt/jet. And yeah usually start at 1 1/2 turns. Just wondering what actual settings are.
 
They are not written in stone, which is why they are adjustable. I usually get it running at full speed, get the engine warm, then adjust the bottom, high speed screw,
until the engine runs strongest, I then idle it down, and adjust the lo screw until the engine runs at it's strongest.

Then I throttle it back up to high, then readjust the high to fine tune it.
 
Fish said:
They are not written in stone, which is why they are adjustable. I usually get it running at full speed, get the engine warm, then adjust the bottom, high speed screw,
until the engine runs strongest, I then idle it down, and adjust the lo screw until the engine runs at it's strongest.

Then I throttle it back up to high, then readjust the high to fine tune it.
Click to expand...

Thanks for the help. I'm used to hi/lo on 2cyls. But Not too much with 4cyls
 
Attached is the service manual for you engine, pages 15-16 have the procedure for adjusting the carbs. I go high speed fuel mixture, low speed fuel mixture, idle speed, then stop. If you go back and adjust high speed mixture you will have to adjust the other two again, as the high speed mixture setting affects the low speed mixture and idle speed. If the engine bogs down between low speed and high speed, open the low speed mixture screw 1/8 turn.

http://www.mymowerparts.com/pdf/Tec...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf
 
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