# 18 HP Kholer carb help



## ArborquipSP (Sep 5, 2009)

It could be something with the governor inside the engine? Do you know your engine mod# and spec#? 

Here is a link to Kohlers website. on the login page click on enter as a guest then on the next page find your engine group, Then pick your engine mod and spec (for parts lookup). In the lower section of the screen there should be a repair manual that you can download and save.

http://www.kohlerplus.com/login.asp

Scott


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## ArborquipSP (Sep 5, 2009)

Any time I like helping out.

Scott


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## ArborquipSP (Sep 9, 2009)

What kohler model ans spec are you working on 
m18 ,ch18 ect. Most likly you have a gear driven governor problem. But I would need more info to be of any help.

Scott


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## ArborquipSP (Sep 9, 2009)

I have seen some govenor gears (item 4 in first picture) break a tooth off (Plastic gear) so it does not spin and push out the govenor pin (Item 5 in first picture) to fight the gov. spring (item 25 in third picture) on the outside of the engine that is hooked to the gov. rod. I have also seen some gov. pins wear the tip off so it does not push on the gov.rod (Item 15 in second picture) when the gov. spins.

If you dont know how a flywheight gov. works here is a short description.

Centrifugal force acting on the rotating governor
gear assembly causes the flyweights to move
outward as speed increases. Governor spring
tension moves them inward as speed decreases.

As the flyweights move outward, they cause the
regulating pin to move outward.
• The regulating pin contacts the tab on the cross
shaft causing the shaft to rotate.
• One end of the cross shaft protrudes through the
crankcase. The rotating action of the cross shaft is
transmitted to the throttle lever of the carburetor
through the external throttle linkage. 
• When the engine is at rest, and the throttle is in
the “fast” position, the tension of the governor
spring holds the throttle plate open. When the
engine is operating, the governor gear assembly is
rotating. The force applied by the regulating pin
against the cross shaft tends to close the throttle
plate. The governor spring tension and the force
applied by the regulating pin balance each other
during operation, to maintain engine speed.
When load is applied and the engine speed and
governor gear speed decreases, the governor
spring tension moves the governor arm to open
the throttle plate wider. This allows more fuel
into the engine, increasing the engine speed. As
the speed reaches the governed setting, the
governor spring tension and the force applied by
the regulating pin will again offset each other to
hold a steady engine speed.


















Scott


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## ArborquipSP (Sep 9, 2009)

I forgot can you feel the govenor fighting you when you grab the gov arm and change the speed? You should feel the flywheights trying to push the engine to idle when you rev the engine by hand if it does not the gov is not working and you most likly will need to pull the rear cover off to check things out. The bad thing is you said this is a generator and they arnt fun to take apart. 

If it does fight you when you rev it by hand it is most likly a bad spring or linkage issue. You did not make your own spring did you? Most generators run at 3600PRMs under load to get 60Hz output. Alot of older ones ran at 1800RPMS to get 60HZ.

do you have any pictures of the linkage on your engine ?

Scott


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## striperswaper (Sep 9, 2009)

do you the history of the machine and this problem?
if somebody brough it to you with this problem sounds like they could have tried ti "fix it" and didn't get the linkage or governor back together right?


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## striperswaper (Sep 9, 2009)

well now you know why the heater burned up....


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## ArborquipSP (Sep 9, 2009)

catfish1 said:


> Hello,
> I can get the correct idle speed by manually pulling back on the "L" bracket (item #2, second pic, governor arm) that is connected by a rod to the throttle plate. There is resistance when I do this. As soon as you let go of the arm, it pulls back to its original place, and begins its high idle. Is it this "L" bracket that is controlled by the governor?
> I will try to send some pics of the linkage. Could a spring be stretched? I have compared the linkage to that of a working unit, and it appears to be identicle.
> I am aiming for 3000 RPM, unloaded. The engine is driving a generator, and a hydraulic pump (all belt drivien), on a HDPE pipe fusion machine. Loaded, with the heater for the unit plugged in, hydraulics loaded up, it should be roughly 2800 RPM, with 240VAC output.
> I think we are on to something with the gears, as no external adjustments seem to have any effect on the idle. I want to thank you again for your help. You have gone above and beyond. Thanks.



Yes #2 in 3rd picture does hook up to #15 in 2nd picture witch touches #5 in 1st picture. When the small gov gear spins it pushes on #5 in first picture and tries to make the engine go to idle and the spring pulls on the L bracket to raise the rpms and fight the gov. If it does not idle when the spring is unhooked the gov is bad. It should just idle only.


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## ArborquipSP (Sep 9, 2009)

catfish1 said:


> Hello,
> Sorry again. The reistance when I manually move the governor arm is just the spring (item #26, last pic), otherwise, there is no resistance at all. Where should the spring (#25) be connected? Thanks.



If you look in the parts brake down on kohlers site #25 is the gov spring and #26 is a Idle spring I think it is not used on the machines I work on so I dont know where it hooks up to.

Scott


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## ArborquipSP (Sep 9, 2009)

catfish1 said:


> Hello,
> Here are the pictures of the linkage for the engine.



Does you engine even have a throttle cable on it or does it just run at 3000rpms and thats it (no Idle or mid throttle ect..)

after looking at the pictures more it looks to be locked in one position correct ?


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## ArborquipSP (Sep 9, 2009)

in the service manual on kohlers site on page 11.23 is the procedure for adjusting the gov lever to the cross shaft that goes in to the engine. I have seen these move and it lets the engine find its own rpms. This is the last thing I can think of before you tear into it.

Scott


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