Carb Adjustment

Old 02-03-03, 06:34 AM
Visiting Guest
Posts: n/a
Angry Toro 2 cycle snow blower

Can any one give me a Idea how to adjust the carb on a s-620 toro snow blower. It is a 2 cycle tecumsen like 3hp { not sure on hp}. It has 2 mixture screws not marked H or L . I replaced the diaphram and now it starts but can use some carb adjustment . Any help would be greatly appreachiated.
Old 02-03-03, 07:36 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 17,938
Received 94 Votes on 87 Posts
Hello Blueranger!

Are the screws side by side? If so, I believe the one farthest from the engine block is the high-speed screw. Turn them both in until they lightly bottom out, then back them out 1 1/2 turns. Crank it up and let it warm up. Then adjust the low screw while engine is at idle...loosen screw just until the engine begins to sputter. Then rev it and adjust the high screw...once you back the screw out enough to get the engine to begin to roll or sputter, then tighten the screw until it begins to stall...count the # of turns you made to get it to begin to stall and loosen the screw half that many.
Old 02-04-03, 02:42 PM
Visiting Guest
Posts: n/a
Hi Blueranger,

Cheese is correct that the L is nearest the engine and H is to the right of it, when you peer through the opening of the bottom engine cover. If you look closer you will see an H to the right of the high speed screw on the carb.

You must have the top engine cover off to adjust that carb. To rev it, I use a long screwdriver to open the throttle. S-620 are a little different than their brother Snowmasters and S-200's. Usually they run well with the L @1 1/4 and the H @ 1 to 3/4 of a turn. Too rich and you will see oil collecting at the muffler joint. Too lean and they die under a load, and restart harder.

When you replaced the diaphragm, did you make sure that the diaphragm was next to the carb, followed by the gasket and then the plastic cover? It is a common mistake, that does effect the running. And was the large disc facing the carb?

When there is no snow to test, I grab the top handle with my right hand, the lower handle with my left, lean the unit forward and apply my body weight over the paddles onto the pavement. (muscle it to hold it in place) If it dies out in 4 or 5 seconds, richen up the H 1/4 turn. (counter-clockwise)

In rare cases (1 out of 100) those carbs with the F-3 marking, are defective. If they start and run ok, but quickly die under a load, no matter how much you open the high speed screw, than I would say that is the case. I run into 2 or 3 of them a good season, that no matter what you do, they crap out under a load. They have a built in check valve, that none of the similar carbs do. Your odds are very, very slim that is the case with yours, but I thought I would make you aware of it, if you do happen to run across that problem. Good luck. 'lint.
Old 12-29-12, 02:31 PM
Join Date: Dec 2012
Location: usa
Posts: 1
Received 0 Votes on 0 Posts
the carb settings on mine are up and down and it runs for 5 mins and dies out

Thread Tools
Search this Thread
Ask a Question
Question Title: