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New Tach, Rpm Questions


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#1 kiddpitt OFFLINE  

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Posted April 26, 2012 - 09:07 AM

I just got a tach and want to make sure I have my '72 LGT 100 running right. I'm idling smooth around 875 RPM and high speed with no load is just under 3500 RPM.

Are these numbers in the right range? The manual says idle should be 1200+/- 75 rpm, but I've also read these K241s like to be around 900. I'm concerned about the high speed RPM too, I don't want to be running too rich. I turned the screw in (toward lean) until it started decreasing from the 3500 RPM and then backed out about 1/8 of a turn from there.

Also, I'm wondering what RPM you guys are running at with a load?

#2 JDBrian OFFLINE  

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Posted April 26, 2012 - 10:11 AM

Typically the engines are rated at 3600rpms and that is the rpms most tractors use as a high limit. On my JD314 they specify 3450 as a under load top speed so it can be somewhat variable. I would check the operators manual for your tracotr and see what is recommended. Also look for the instructions for setting the high speed adjustment in the owners manual or the manual for the specific engine in your tractor. If you are running under a heavy load you want to be on the rich side of the adjustment range.

#3 kiddpitt OFFLINE  

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Posted April 26, 2012 - 12:15 PM

Thanks, I keep a hard copy of the manuals (owner's, service, etc) in the garage and use them alot.

Before now, I've never had a tach at my disposal & was just curious about people's real world experiences with where their tractors/engines were happy.

In addition to the idle RPMs, I've also read that it's not a bad idea to run these engines a little rich (because of the cast iron block & alluminum head) to help prevent overheating. But I'm also scared of carbon buildup from being too rich. So I'm not really asking how to adjust the carb, I'm asking more if people know what RPM ranges their engines are happy in.

Edited by kiddpitt, April 26, 2012 - 12:28 PM.


#4 KennyP ONLINE  

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Posted April 26, 2012 - 05:43 PM

Finding what rpm an engine is happy in changes from one engine to another. If your seems happy where it's at, then leave it alone. I don't have a tach, so I just go by the sound it's making!




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