Carburetor Adjustments? - Snowblower Forum : Snow Blower Forums
 
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post #1 of 8 Old 01-04-2012, 06:33 PM Thread Starter
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Carburetor Adjustments?

I just bought a new after market carburetor for 26 year old Toro 521( 2 months ago). We have had near zero snow this winter so far. My Toro surges at idle up and down. I start it in my garage just to keep the gas flowing through the carb. I have not adjusted the idle screw yet. The 5 horsepower Tech engine smooths out when I click the choke on one click toward choke. Is this a tell tail sign that the motor is too lean at idle? I bought a carburetor that had the "power valve" adjustment under the bowl as well. Should I make the mixture more rich? I never know if I should go with the heater box on or off for carburetor adjustments

Original owner of a low mileage 1986 Toro 521 2 stage
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post #2 of 8 Old 01-04-2012, 08:33 PM
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Carb adjustments

Talon

I'm making some general assumptions here, first off the carb resembles this one:

It won't be exact because this is a 7 HP Tecumseh. Don't worry about that. Do care about whether the one you have is a float type carb with 2 adjustable jets, because that's what I'm referencing. If yours isn't then disregard this.
There are 2 jets on it, one on the left side as facing it, just above the bowl. One on the bottom of the bowl. The side is the low/midrange jet while the bowl bottom one is the high speed.
Starting adjustment is 1 full turn on the low/midrange and 1 1/2 turns on the high speed.
Heat box off, start the engine and get choke off as soon as you can. I usually start with the high speed. Adjust the high jet till it starts smoothing out. Keep going through the point it's smooth till it starts going rough again. split the difference and try it there, make any final adjustments to keep it running smooth. Might have to do a partial adjustment with the choke on, get it close then turn the choke off and adjust further.
Throttle back to about 1/2 and do the same with the low/midrange jet.
Once you have it all adjusted, gofrom low to high rpm's and back down and see if it's smooth or not. If not, adjust some more.
When you're done, put the heater box back on.

There is a Tecumseh engine manual online somewhere but I don't have the name. If you have another carb, the manual should cover it.

Good luck
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post #3 of 8 Old 01-05-2012, 06:03 AM
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Most heater boxes have a hole in the side so you can access the idle mixture screw and the low rpm adjustment screw. The engine must be warmed up before adjusting. The idle mixture screw on the side of the carb will also affect the full speed when the engine has no load on it.


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post #4 of 8 Old 01-06-2012, 05:08 PM
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Adjustments

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Originally Posted by Shryp View Post
Most heater boxes has a hole in the side so you can access the idle mixture screw and the low rpm adjustment screw. The engine must be warmed up before adjusting.
Very true on adjusting with the heater box on. My problem usually is I can't find my long screwdriver at the time, so I have to use a short on and that puts my hand right in line with the exhaust if I do it through the hole in the heater box. At least with the box off, I can angle the screwdriver out or use a short one to stay away from hot items.
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post #5 of 8 Old 01-06-2012, 10:27 PM Thread Starter
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Originally Posted by HCBPH View Post
Very true on adjusting with the heater box on. My problem usually is I can't find my long screwdriver at the time, so I have to use a short on and that puts my hand right in line with the exhaust if I do it through the hole in the heater box. At least with the box off, I can angle the screwdriver out or use a short one to stay away from hot items.
Kinda sounds like HCBPH's girlfriend.......If her heater box is on......She said that he could not find a "long screwdriver at the time".....Hahahaha......someone needs to find some humor here.........LOL! >>>>>> Talon Luv ya HCBPH.......

Original owner of a low mileage 1986 Toro 521 2 stage
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post #6 of 8 Old 01-06-2012, 10:37 PM
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Originally Posted by Talon1189 View Post
Kinda sounds like HCBPH's girlfriend.......If her heater box is on......She said that he could not find a "long screwdriver at the time".....Hahahaha......someone needs to find some humor here.........LOL! >>>>>> Talon Luv ya HCBPH.......
Shhhhhhhhhhhhhh - don't tell my wife!
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post #7 of 8 Old 01-06-2012, 11:18 PM Thread Starter
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Shhhhhhhhhhhhhh - don't tell my wife!
Too late now buddy.......she told Shryp and he told all the other moderators ..... HAHAHA..........We have no daayuum snow so we can have some fun off topic here........

Original owner of a low mileage 1986 Toro 521 2 stage
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post #8 of 8 Old 01-06-2012, 11:23 PM
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I'll bet an additional 1/2 a turn out/left and you'll be ok, on the idle mix screw on the side not the one on the bottom. BTW NO SNOW HERE EITHER!!!! Actually thinking I may use my boat soon. Harbors are open and salmon are in shallow!!
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