Carb adjustment - Snowblower Forum : Snow Blower Forums
 
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post #1 of 8 Old 11-05-2019, 09:11 PM Thread Starter
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Carb adjustment

I started my 1979 724 Ariens for the first time this season. I did an oil change at the end of last season. I could never adjust the carb to run smooth and idle properly. It has a H70 Tecumseh. Any tips would be appreciated. The leakage is on the second hole in the governor arm on YouTube it's in the first hole at the tip. It pops and shacks. I keep adjusting the main screw and the idle screw. It also likes to run on 10% closed choke.
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post #2 of 8 Old 11-06-2019, 01:10 AM
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If it's popping (backfiring), your valves may need adjustment.Typically these carbs are pretty easy to tune if all else is good. Basically, go to full throttle and engage the blower (whatever load you can add) and set the needle on the bottom of the bowl to the center of the range between where it wants to die. Then go to idle and do the same with the needle on the side. Repeat to verify. If it tends to stall when you hit snow, open the bottom needle a little at a time until it does not, and recheck idle. Done . . .

Also, not sure if you have cleaned the carb, but that is important, as are the small O rings on the needles.
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post #3 of 8 Old 11-06-2019, 09:02 AM
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donyboy73 has a pretty good video on it. otherwise i agree with tadawson

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post #4 of 8 Old 11-06-2019, 07:05 PM
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Check and Clean the Ignition Points.
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post #5 of 8 Old 11-07-2019, 06:52 AM Thread Starter
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Quote:
Originally Posted by Jackmels View Post
Check and Clean the Ignition Points.
I don't want to take it apart so close to the snow season. I don't want to be stuck without a snowblower. I had that happen to me last year because I didn't get belts in time.
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post #6 of 8 Old 11-07-2019, 07:26 PM
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post #7 of 8 Old 11-08-2019, 05:14 PM
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Quote:
Originally Posted by malisha1 View Post
I started my 1979 724 Ariens for the first time this season. I did an oil change at the end of last season. I could never adjust the carb to run smooth and idle properly. It has a H70 Tecumseh. Any tips would be appreciated. The leakage is on the second hole in the governor arm on YouTube it's in the first hole at the tip. It pops and shacks. I keep adjusting the main screw and the idle screw. It also likes to run on 10% closed choke.
On the governor linkage, does the throttle open fully in the second hole you are using? If not would the first hole move the throttle to full throttle with engine not running? The setting you want will open the throttle fully against its stop. The governor controls engine speed to a particular setting, like 3,600 rpm, but that is controlled on the other linkage off the governor arm.

Since adjusting the carb is not resolving your problem, makes sense to move on to a different solution.

@Jackmels has a great deal of experience, so perhaps your question of him should be how to access the magneto points and how to adjust. I got a generator from a neighbour for my son, but it did not run well. Replaced the old spark plug and cleaned the carb and little improvement. So I checked the magneto (no points on this electronic version) and cleaned up the contacts which were dirty and adjusted the gap to 0.010" (10 thou inches) and the engine ran very much better. I just lucked into my needed solution while Jack would know this from years of experience. Points lose their adjustment over time due to wear and other factors, they don't last forever and will cause poor ignition performance or no ignition at all.

Good luck.

2015 Ariens Platinum 30 SHO - model 921040
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post #8 of 8 Old 11-21-2019, 01:14 PM
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I have the same year machine. If that carb is original (you know it's history) then it definitely needs a rebuild or replacement. I prefer rebuilding the OEM carb than a Chinese knock off.
The mention of the points and valves is true too. I replaced my original points about 5 years ago.
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