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FlashandFlare

CH18 carb adjustment and recommended RPM's

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FlashandFlare
I just got through with replacing both head gaskets on my tractor (late model'ish Sovereign with a CH18s) and I am looking for either Stock or what others have found to be better than stock carb/choke linkage settings and correct governor spring location hole. I had it all apart and I am confident that I have the cables back in the correct holes as I took pictures of it pre-removal, but now that it all back together the engine seems very slow to respond to throttle movement. From idle up to full throttle it makes no diff in RPM until you have moved the throttle lever at least 70% through the travel and then the RPM's increase like normal. I also noticed that that machined screw with the locking nut that is on them plates was loose so I am not sure that is adjusted to the desired location. Can someone post some pics or some detailed specs please ? Also what RPM should it be idling at ? Thanks F&F

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RayS


Do you have the throttle and choke cables in the above holes? Can you post pictures?


Heres some pictures. I believe my idle is set at 1600 or 1800 RPM`s and top RPM is at 3600. Been trying to find where I got the information for idle speed. I have a bunch of manuals to look through and haven`t found it yet. I may have got the info from BLT, but I will keep digging for it.


It appears that I didn`t have my throttle cable in the correct hole when my Command was in my 919H. It ran fine in that hole though. I have since installed the motor in a Sovereign 18 and I wonder if I have it set in the same hole as the diagram above. Will have to check that, but I have no issues with mine.

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FlashandFlare
I know for a fact mine is idling alot lower than 1600, I just got a photo tach and I will check it again tomorrow. I can post pictures, I will have resize the current ones I have though. I just looked and my gov spring is in the 3rd hole from then end and I was looking on eBay tonight to see if I could find some other examples and I seen one that had his spring in the 2nd from farthest in. My choke and throttle cable are in the location just as you posted above. What about that fine threaded silver bolt with the jam nut, where should that be at ?

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RayS
That bolt you are talking about is the high speed stop and mine is set at 3600 - 3650 rpm`s. I have never moved the governor spring so it is set where the factory put it.

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FlashandFlare
quote:
Originally posted by RayS
That bolt you are talking about is the high speed stop and mine is set at 3600 - 3650 rpm`s.
forgive my ignorance, but I did not know that screw was the high speed stop, I thought max rpm was controlled by cable travel, like loosening the lock down screw and sliding the cable sheath for or aft. Learn something new everyday.

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DanD
One place you may have gotten the idle spec is right off the Kohler parts page. If you look at the Kohler Spec 62513 which is for Simplicity, it specifies a 1800 RPM idle speed for the CH18 engine.

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RayS
Dan, I believe that is where I did get that info. from. It states right there on the there site 1800 idle speed and 3600 high speed rpm`s . Repair manual states to not go over 3750 rpm`s with no load.

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MysTiK
quote:
Originally posted by DanD
One place you may have gotten the idle spec is right off the Kohler parts page. If you look at the Kohler Spec 62513 which is for Simplicity, it specifies a 1800 RPM idle speed for the CH18 engine.
I, too, am having a senior moment, trying to recall when, where, how, the 1800 rpm figure appeared, in my world; but I do believe it was from my 700-series Allis Chalmers manual, involving a Kohler K341 (of course) and a Sundstrand hydro. Elsewhere, I saw the motor alone recommended idle at 1200rpm. I concluded the specified 1800 was important for maintaining adequate spin rate of the Sundstrand. I am unsure what trans is involved re this discussion. In the background is a concern that too slow a spin rate can be deleterious to the longevity of the hydro itself. In otherwords, it's not about the engine at all (perhaps). Note this might seem irrelevant to the current discussion; but might, in fact, be pertinent: which is how I come to even mentioning it. My cue was taken from DanD saying the Kohler spec was "for simplicity"; that is to say, this application of the Kohler engine.

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FlashandFlare
My idle rpm was 968.7 so she was just a tad slow ya think ?, dunno who adjusted it like that cause I have never touched it. Oh well, it's fixed now. Its set at 1793-1807 and Max unloaded RPM is at 3685-3700 Still don't know why the throttle is still so slow to react when increasing RPM but is normal when decreasing RPM ?

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PhanDad
I also have this issue of throttle lever response. Rather than hijack this thread I'm going to start a new one. Maybe someone can suggest a solution. Or maybe "it's the way it is" with a CH18.

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FlashandFlare
quote:
Originally posted by PhanDad
I also have this issue of throttle lever response. Rather than hijack this thread I'm going to start a new one. Maybe someone can suggest a solution. Or maybe "it's the way it is" with a CH18.
No worries about hijacking, all that matters is that we all become the wiser. Has yours always been this way ? or was it something that just started ? F&F

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PhanDad
I picked up a 75th Anniversary tractor that had the original Triad replaced with a spec 62501 CH18, but the install was a hack-job. I reinstalled the engine; so I've always had the issue.

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FlashandFlare
Weird as mine was fine before I removed my engine to do the headgaskets, is it possible that we both ironically did the same mess up reinstalling ?? Does yours run fine otherwise ? Does yours respond fine to decreasing the throttle as mine does ? Mine is fine in all aspects other than the throttle response.

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