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#1 artbuc OFFLINE  

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Posted July 27, 2015 - 05:23 PM

On Ariens GT 18 and Gravely 18-H. These two are identical twins with Kohler M18S engines. According to the FSM, they are governed at 3250 and idle at 1200. Thought mine was running a little slow and finally got around to checking it. Was surprised to find no load WOT at 2400. I rigged a replacement throttle cable years ago and guess I never had it right since then.

 

Also, I can not get close to that wide range between idle and WOT. When I set WOT at 3000, it will not idle below 1800.

 

Just wondering where you folks set your idle and WOT speeds? Thanks.


Edited by artbuc, July 27, 2015 - 05:37 PM.


#2 Chopperhed OFFLINE  

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Posted July 27, 2015 - 06:36 PM

Does the throttle setup (cable/pushrod) allow full travel of the butterfly shaft on the carb?

 

Idle should be set at the proper idles speed. The throttle setup must allow full operation of the carb.


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#3 artbuc OFFLINE  

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Posted July 27, 2015 - 06:44 PM

Does the throttle setup (cable/pushrod) allow full travel of the butterfly shaft on the carb?

 

Idle should be set at the proper idles speed. The throttle setup must allow full operation of the carb.

 

I have an extra long cable (throttle, that is) which I have looped around the air intake. I am thinking the loop provides enough slack that the throttle is not opening all the way. I have a new throttle on order. Ariens is showing just 16 left and I do not know if they are going to make more.

 

As far as numbers go, do you operate WOT at 3250?


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#4 Chopperhed OFFLINE  

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Posted July 27, 2015 - 07:41 PM

I don't personally, only as a last ditch push for extra power. I try to stay at around 3/4 max for the heavy loads, and 1/2 for light stuff.

 

Unless of coarse, I need a little extra push.


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#5 shorty ONLINE  

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Posted July 27, 2015 - 08:37 PM

I just happened to think of this on Saturday while mowing with the Gravely. I don't think that it idles as low as it should. I don't have a gauge to check the rpm, but going by engine sound, it just seems it idles high. One more thing to to add to the list to check out further.



#6 larrybl ONLINE  

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Posted July 27, 2015 - 09:39 PM

Are these pressure or splash lubed?

Pressure lube you can idle pretty low and not have an issue.

Splash lubed, Full RPM is recommended.

https://www.youtube....h?v=plCnsUhQ4bg


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#7 Billy M OFFLINE  

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Posted July 27, 2015 - 10:45 PM

Also...A fast idle on an air cooled engine isn't a bad thing. Air cooled engines aren't recommended to let idle for extended periods due to the lesser air flow at idle. They like to be ran at higher RPMs.

As far as running...I'm with Chopperhed. I usually run 1/2 to 3/4 throttle and have never had any issues. IMO...If you need to run at full throttle, you need a bigger engine for more power or a better gear ratio for what you want to turn, so you're not pushing your engine so hard.
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#8 artbuc OFFLINE  

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Posted July 28, 2015 - 02:06 AM

Also...A fast idle on an air cooled engine isn't a bad thing. Air cooled engines aren't recommended to let idle for extended periods due to the lesser air flow at idle. They like to be ran at higher RPMs.
As far as running...I'm with Chopperhed. I usually run 1/2 to 3/4 throttle and have never had any issues. IMO...If you need to run at full throttle, you need a bigger engine for more power or a better gear ratio for what you want to turn, so you're not pushing your engine so hard.

Ok, but what is 1/2 to 3/4? The Kohler M18S has a maximum allowable speed of 3600. The Ariens/Gravely tractors are governed at 3250. Unless I am mistaken, these tractors are designed to run at governed speed to get the right tip speed on the mower blades, for proper operation of the hydro drive and proper engine cooling/lubrication. Are you saying I should try to cut grass at 1800 rpm engine speed?

I should not have used the term "WOT" which is 3600. WOT engine speed is not governed speed.

Edited by artbuc, July 28, 2015 - 03:33 AM.


#9 Alc ONLINE  

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Posted July 28, 2015 - 05:19 AM

Never checked mine but I'm like most , normal tractor jobs like using the cart or pulling the lawn sweeper , pretty much half  throttle , cutting grass is just about full to full,, if the grass is high then  full throttle . That's on the JD 318 .I think the Power Kings want 3600 when cutting grass , tilling snow blowing ect  I'll see if I can borrow a non-contact tach from the other garage just to see what some of mine are really running at . It might scare me lol



#10 JDBrian OFFLINE  

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Posted July 28, 2015 - 10:36 AM

I'd go with a faster idle. Seems like something is off there in the linkage. Typically you have no trouble getting max. RPMs out of the adjustment procedure.  The JD 314 I have has an official idle speed of 2200. In that case I think it is JD trying to keep the engine speed above the resonance of the rubber engine mounting system.


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#11 artbuc OFFLINE  

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Posted July 28, 2015 - 01:58 PM

I'd go with a faster idle. Seems like something is off there in the linkage. Typically you have no trouble getting max. RPMs out of the adjustment procedure. The JD 314 I have has an official idle speed of 2200. In that case I think it is JD trying to keep the engine speed above the resonance of the rubber engine mounting system.

Thanks JD. I am hoping the new throttle cable will expand the speed range. Talked with Ariens Tech Support today. They confirmed mowing and throwing snow should be done at full governed speed of 3250.

I assume fom your post that you operate at full throttle too?

Edited by artbuc, July 28, 2015 - 02:27 PM.


#12 Billy M OFFLINE  

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Posted July 28, 2015 - 11:21 PM

Ok, but what is 1/2 to 3/4? The Kohler M18S has a maximum allowable speed of 3600. The Ariens/Gravely tractors are governed at 3250. Unless I am mistaken, these tractors are designed to run at governed speed to get the right tip speed on the mower blades, for proper operation of the hydro drive and proper engine cooling/lubrication. Are you saying I should try to cut grass at 1800 rpm engine speed?
I should not have used the term "WOT" which is 3600. WOT engine speed is not governed speed.


1/2 to 3/4 throttle on my tractors seems to run on the higher end of the scale. I've never put a tachometer on one, but I'm pretty sure they are running faster than 1800 RPMs. I've never had a tip speed issue on a garden tractor. I'm not mowing fast enough for it to be an issue. On the other hand, a zero turn running 8+ MPH mowing grass...yeah, you're going to need that tip speed at full throttle.

#13 artbuc OFFLINE  

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Posted August 05, 2015 - 03:09 AM

I have an extra long cable (throttle, that is) which I have looped around the air intake. I am thinking the loop provides enough slack that the throttle is not opening all the way. I have a new throttle on order. Ariens is showing just 16 left and I do not know if they are going to make more.
 
As far as numbers go, do you operate WOT at 3250?


This was the issue. With new throttle control, I have nearly full range from 1200 idle to 3000 max.
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