# Adjusting new carb with high and low speed jets



## theoldwizard1 (Nov 23, 2011)

I have been messing with small engines for over 30 years but I am at the age where my memory of things I did way back when is pretty rusty !

I am trying to bring an old Ariens ST724 with a 7 HP Tecumseh Snow King engine back to life after many years of being "rode hard an put away wet". The carb bowl has some serious corrosion and the float has fuel in it. There are a dozen or more aftermarket replacement carbs (original part number 631954) available from various different companies so I ordered on made by HOOAI from Amazon.

My question is, *how to you adjust the high and low speed jets ? Which do you start with first ?*


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## JLawrence08648 (Jan 15, 2017)

Warm it up first, give it about 5 minutes. For either the low speed or high-speed the adjusting is the same. You turn the screw in until you notice a change in idle or roughness, then you turn out until you notice the change, then you turn in as you want the midpoint between the two. However I like to turn it in until it starts to speed up then I back out a quarter or a half a turn. You do not want it when it speeds up because now you are leaning out the engine too much. You adjust the low-speed which is on the side of the carburetor first, then you adjust the high speed on the bottom. You want it idling when you just low speed and you want it running fast when you adjust the high speed. You may find you have to readjust the high-speed under load, that is when you are blowing snow.


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## 10953 (Sep 4, 2017)

are you asking for the basic bench setting before starting? if it is a adjustable carb with low and high speed . i try for 1 1/2 out for the low speed and 2 1/2 for high speed, then when warm do as JL does 
good luck you're not alone with the mature grand pop mind


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## 351beno (Oct 12, 2017)

The basic staring point is 1 1/2 turns out for the high speed "bottom" and 1 1/4 turns out for the low speed "side". I always start with the high speed then go to the low speed. After those are set rev it up from low to high and if you get black smoke turn the high speed in a little.


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## theoldwizard1 (Nov 23, 2011)

I am not having a lot of success following those excellent directions !

First, just to my ear, WOT sounds much higher than typical. I am pretty certain I have the governor to throttle and throttle to carb linkages in the correct holes. If you you think it will be worth it, I'll snap a picture.

There is a small amount of surging. Throttling down has to be done carefully or it will stall and it is not as slow as I would think it should be. Quck throttle ups also cause a stall.

Second, this thing smells like it is running super rich even though I started at the same setting as the old carb (3/4 out on the idle and 2 on the high speed).

Last and this has happened twice, after running about 7-10 minutes at 3/4 throttle, the engine just quits. I got it to restart with a couple of pulls the first time, but the second time I am getting nothing even with the electric starter (the grounding wire is disconnected).


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