Jump to content

Garden Tractors and Parts on eBay



Welcome to Garden Tractor Talk Forums

GTtalk is the place to go if you are a garden tractor collector or someone looking for information on your favorite tractor. We have interactive forums, registry, tractor / implement manuals, photo galleries, articles, show coverage, tech tips and how tos, classifieds and much more.

You are currently viewing our site as a guest which provides limited access. By joining our free community you will have access to post topics, communicate with other members, vote on polls, upload images and attachments as well as many other special features. Registration is quick and easy and best of all completely free!

If you have any problems with the registration process or your account login, please contact us.

Photo
- - - - -

Kohler Govenor Adjustment


  • Please log in to reply
4 replies to this topic

#1 maddhorse OFFLINE  

maddhorse

    Tractorholic

  • Senior Member
  • Member No: 4719
  • 52 Thanks
  • 85 posts
  • Location: Auburn, Maine

Posted August 21, 2011 - 04:59 AM

After reading this I got it. Information about the Kohler Carburetor, Various Fuels and Fuel Systems
How to Set the Governor Adjustment - Top of page




If your engine revs with no closing of the throttle shaft, or surges, then the governor is probably out of adjustment. To set the governor on a Kohler (or virtually any engine)...
  • Install all the throttle linkages, governor parts, etc., in their respective places. look for wear in the holes in the governor and throttle to see the most likely place the spring was last.
  • Loosen the bolt that clamps the lever to the governor cross-shaft that protrudes out of the engine block.
  • With the throttle plate blocked in the wide open position, rotate the cross-shaft counterclockwise until it stops. Now tighten the bolt.
  • That's all that's to it! But if this doesn't fix the problem, then perhaps a governor part inside the engine is damaged or the screws came out of the throttle plate, where it fastens to the throttle shaft.
  • And it doesn't matter how long or short the link is because the governor is adjusted by the clamp on the cross shaft. Actually, We don't know why Kohler made the link adjustable. It serves no purpose to lengthen or shorten it.
  • You can also go here for further details and pictures: Cub Cadet FAQ.
Posted Image Do not mistakenly rotate the cross shaft clockwise (opposite rotation than what it shows in the drawing above) until it stops, tighten the clamp and then run the engine! Doing this could cause the lever (see below) to jam into the governor flyweights, breaking off the lever and/or possibly destroying the governor gear assembly.
If the governor cross-shaft (the shaft that protrudes from the block) gets bent due to rough handling of the engine, and if it's not bent too bad, just use a hammer to straighten it. It's made of mild steel. But if it's bent severely and breaks off, it must be replaced. If this happens, usually the bushing/nut (Kohler part # 235476) will break and it will need to be replaced, too. Or, if the above adjustment was attempted, and the governor shaft keeps rotating without stopping, this means the flat lever on the shaft has broken off. This will allow an engine to operate dangerously at wide open throttle at all times. To fix either of the above, another governor shaft (Kohler part # A23525601S) must be installed. To install another shaft, the entire engine must be completely disassembled. This means EVERYTHING inside the engine block (crankcase) will need to be removed. And then the replacement shaft can installed from inside the crankcase. But before the old shaft is removed, the bronze bushing/nut on the outside must first be removed. The governor gear assembly doesn't have to be removed. The shaft lifts out from inside the crankcase and is installed in reverse order of removal. Posted ImageAnd it'll be a good idea to place a small bead of weld on the flat lever to secure it to the shaft to prevent future breakage. (We think this is something that Kohler should have done.) We realize that this is a lot of work just to replace a small [important] part, but it must be done in this way. There is no other way to replace it.

Edited by maddhorse, August 21, 2011 - 07:55 PM.
Brian Miller is the original Author

  • tractorman604, dan the tractor man, HDWildBill and 3 others have said thanks

                       

#2 maddhorse OFFLINE  

maddhorse

    Tractorholic

  • Senior Member
  • Member No: 4719
  • 52 Thanks
  • 85 posts
  • Location: Auburn, Maine

Posted August 21, 2011 - 08:00 PM

Information about the Kohler Carburetor, Various Fuels and Fuel Systems

Identification of Carter and Kohler Carburetors -
Kohler (or Carter [model N], that was used only on the early 10hp engines) made four types of carburetors for their K-series single cylinder 10hp through 18hp engines and KT-series opposed twin cylinder engines.
  • Posted ImageThe first carburetor is a number "26". It's used on the 10hp (model K241), 12hp (model K301) and small opposed flathead twin cylinder engines. It has a 26 millimeter or 1.07" diameter throttle bore. The venturi measures .812" in diameter.
  • The next is a rare one, number "28". It's used mostly on the 14hp (model K321) and on some 16hp (model K341) engines. It has a 28 millimeter or 1.17" diameter throttle bore. The venturi measures .937" in diameter.
  • The third is a number "30", which is also used on the 14hp, 16hp, 18hp OHV (model K361) and larger opposed flathead twin cylinder engines. It has a 30 millimeter or 1.200" diameter throttle bore. The venturi measures 1.000" in diameter.
    • The venturi in the #30 carburetor that's used only on the 18hp OHV single cylinder engine measures .1.062" in diameter.
  • By the way - the numbers on the carburetor mounting flange refers to part numbers. Please refer to Kohler publications TP-2379 single cylinder engine manual, and P-2377-D carburetor reference manual.
The size number on all Carter [model N] and Kohler carburetors is embossed inside the carburetor and can be seen by looking inside the upper part of the choke end, just above the venturi. A "26" carburetor has a 26 millimeter diameter throttle bore, which converts closely to 1.024 inches (26 ÷ 25.4 = 1.024"), but actually measures 1.07". A "28" carburetor has a 28 millimeter diameter throttle bore, which converts to 1.102 inches (28 ÷ 25.4 = 1.102"), but actually measures 1.17". And a style "30" carburetor has a 30 millimeter diameter throttle bore, which converts to 1.181 inches (30 ÷ 25.4 = 1.181"), but actually measures 1.200". If there's no number embossed, you'll need to accurately measure the diameter of the throttle bore to determine the size carburetor you have.
Airflow -
  • The venturi in a stock #26 carburetor measures .808" in diameter, and flows 74 CFM. With the venturi removed (bored out venturi, making it have an unrestricted straight-through throttle bore), this carburetor will flow 98 CFM (cubic feet per minute), which is about 1.3 times or 65% more airflow.
  • The venturi in a stock #28 carburetor measures .920" in diameter, and flows 84 CFM. With the venturi removed, it'll flow 107 CFM, which is about 1.3 times or 75% more airflow. A bored-out #26 carburetor will out-perform a stock (non-bored) #28 carburetor at high rpms. And the throttle bore in a #26 Carter or Kohler carburetor cannot be bored large enough to match the size of a #28 carburetor. The throttle bore "wall" is simply too thin.
  • The venturi in a stock #30 carburetor measures .920" in diameter, and flows 84 CFM. With the venturi removed, it'll flow 110 CFM, which is about 1.3 times or 77% more airflow. A bored-out #26 carburetor will out-perform a stock (non-bored) #30 carburetor at high rpms. And the throttle bore in a #26 Carter or Kohler carburetor cannot be bored large enough to match the size of a #30 carburetor. The throttle bore "wall" is simply too thin.
  • NOTE: Boring of the venturi in the carburetor alone won't help to increase engine performance. To increase the overall airflow in and out of the combustion chamber for improved engine performance, and if sanctioning club's rules allow this, the intake (and exhaust) port runners must be enlarged, too. This is called "porting an engine." The [stock size] valves will also need to be reworked for more airflow. Or larger valves and a bigger cam will need to be installed.
For pulling competition, carburetor design and size depends on port sizes, valve sizes, if the intake valve and seat have 30°/31° angles and undercut heads, and the cam profile (lift and duration) is important. If an engine has stock ports, valves and cam, a plain stock carburetor can be used. But if the ports and valves have been reworked for more airflow, and a bigger cam is going to be used, then a bored-out carburetor with a 1" (.995" NQS legal) venturi can be used for best performance.
The 26mm carburetor obviously has a smaller throttle bore. Therefore, is restricted as to how much air can flow through it, even with the venturi removed. It'll work excellent on a hot 10hp or mild 12hp engine, but the larger 28mm and 30mm carburetors flows more air, 7.7% more for the 28mm, and 15.5% more for the 30mm. Which are ideal for a hot 12hp and larger engines with porting, polishing, bigger valves and a big cam. If you feel that using a single 30mm carburetor isn't enough for your particular engine, then either a "Super Carb," Dellorto, Mikuni, S&S Super D or a twin Kohler carburetor setup (on a "Y" intake) should be used.
If you have a 14hp Kohler engine, and you can't find a #28 or #30 carburetor, then a #26 carburetor will work just fine for ordinary yard use. Personally, we ran a stock #26 on the 14hp engine that's on our 6,000 lb. self-propelled pulling sled for 10 years and the engine didn't lack any power whatsoever.

Identification of Walbro Carburetors -
The Posted ImageWalbro carburetor originally come on all Magnum engines, and are very good, reliable and they last a long time before requiring service. The only problem with Walbros if you want to use one on a pulling tractor or for high performance application is they can't be bored out or modified in any way because the throttle bore wall (where the venturi is located) is too thin. Therefore, they're limited to how much air they can flow. The US government told Kohler and all other small engine manufacturers to redesign the carburetor that's used on their engines so they'll produce less air pollution. So they did away with the old style Kohler carburetor and started using the redesigned emissions-controlled Walbro carburetor. The older Walbros have an adjustable high speed main jet, which is located on the lower side of the carburetor. But the newer ones have a fixed or non-adjustable high speed main jet. This is to keep people from setting the air/fuel ratio too rich and create more air pollution.
Walbro carburetors work great for ordinary lawn and garden equipment, general yard work and they're perfect for basic stock low rpm/low-performance pulling tractors with an engine that's governed to a maximum of 3,200 rpm with a fixed main jet, or at 3,600 rpm with an adjustable main jet. A carburetor with a fixed high speed main jet is limited to just 3,200 rpm and should never be operated faster for an extended length of time. Although the venturi cannot be bored out on a Walbro, they work equally as well as the older Carter or Kohler carburetors when used on a stock engine. The main jet in the newer Walbro carburetors are calibrated at the factory to provide the engine with just the right amount of fuel at 3,200 rpm. Therefore, the fixed jet inside the carburetor cannot be replaced with an adjustable one.
Walbro carburetors having a fixed main jet are designed with emission controls in mind to run leaner to create less air pollution. However, the main problem with most Walbros having a fixed main jet is during cooler weather operation. During cool weather, and running at 3,200 rpm, the engine will sometimes run too lean on fuel and operate erratically. To fix this, simply enlarge the hole in the main jet a few thousands of an inch. The factory main jet hole size for 100% gasoline is 3/64" (.047"). If necessary, enlarge the main jet and fuel inlet holes with a #55 (.052") drill bit. That's a .0052" difference. After doing this, for cool weather, the engine should run better, last longer and produce more power. But don't enlarge the main jet hole too much! A too big of a hole will cause an engine to run too rich on fuel, making it blow black smoke out the exhaust and possibly fouling the spark plug. If the hole is made too large, the carburetor will be useless for gasoline, and E-85 fuel must be used. But if an engine is going to be used only during warm weather and if it runs okay [during warm weather], don't enlarge the main jet hole.
On the newer carburetors with a fixed main jet, the main jet hole may need to be enlarged .002"-.003" to give the engine a little more fuel so it'll run better at higher rpms. Otherwise, the engine could "burn up" or wear out prematurely due to the lean air/fuel mixture. We have an assortment of tiny drill bits that we use on our customer's lawn & garden equipment carburetors.
Posted Image A new style Walbro carburetor with a fixed high speed main jet should never be used on a non-governed (wide-open throttle) engine or on an engine that's going to turn at 3,200 rpm! The reason for this is because if an engine operates faster with a carburetor having a fixed high speed main jet, it'll run too lean on fuel at high rpm (it'll draw much more air than fuel), which will cause the combustion chamber to overheat and the excessive heat will likely damage the piston and rings and possibly warp the cylinder head and/or exhaust valve or even crack the cast iron engine block. A lean fuel mixture can also melt away part of the aluminum in the combustion chamber of an aluminum block engine.
The size number on all Walbro carburetors is embossed inside the carburetor and can be seen by looking inside the upper part of the choke end, just above the venturi. A "52" carburetor has a 26 millimeter diameter throttle bore, which converts closely to 1.024 inches (26 ÷ 25.4 = 1.024"), but actually measures 1.07".
Posted ImageAnd being the old-style 7hp (K161) and 8hp (K181) Carter model N carburetor venturi can't be bored out either, the only option for pulling competitively with these is to fabricate an adapter to fasten to the intake port on the engine block and use a #52 Walbro or #26 Carter or Kohler carburetor.
The best way to determine which engine any particular carburetor is made for is to measure the diameter of the throttle bore. Because a set of numbers that's stamped on the carburetor body mean nothing, not even to Kohler Engine dealers. If a carburetor measures .822" (13/16"), then it's made for the 7hp or 8hp engines. If it measures 1.07", then it's for the 10hp or 12hp engines. And if it measures 1.17" or 1.2", it's for the 14hp, 16hp (flathead) or 18hp OHV engines.
And the new style Walbro carburetors are notorious for leaking gas, even after installing a new kit with a new float valve and seat. This is undoubtedly how big business keep selling new carburetors nowadays. Anyway, most newer Walbro carburetors aren't worth rebuilding. If it can be done, install a rebuilt Carter or Kohler carburetor instead. If it's on an engine that requires a difference bolt pattern for mounting the carburetor, an adapter may have to be made. But the older Walbros are worth rebuilding, because they're much like the Carter and Kohler carburetors. They were made back in the day when most businesses took pride in their products.
Posted ImageIf the threads strip out where the float bowl retaining bolt goes, to fix this, cut about 1/8" off the bottom of the protruding part and reinstall the float bowl and retaining bolt. It'll tighten the bowl slightly more onto the carburetor, and you'll need to check and see if the two side fuel feed holes aren't blocked or partially blocked with the retaining bolt installed and tightened. If they are blocked, they can be redrilled so the fuel will reach the main jet. This works the same with an OEM retaining bolt and an aftermarket bottom adjuster. Be sure to back the adjuster out before installing so the needle won't jam into the main nozzle and get damaged. And if the threads strips again, you may have to get another carburetor body. Because the metal is simply too thin for welding or a Heli-Coil insert.
  • dan the tractor man, Trav1s, LTD and 1 other said thanks

#3 maddhorse OFFLINE  

maddhorse

    Tractorholic

  • Senior Member
  • Member No: 4719
  • 52 Thanks
  • 85 posts
  • Location: Auburn, Maine

Posted August 21, 2011 - 08:04 PM

http://gardentractorpullingtips.com/carbfuel.htm

you can get more info from this link.

#4 Texas Deere and Horse OFFLINE  

Texas Deere and Horse

    RED Wild Hogs, Horses & Deeres

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 1435
  • 8,578 Thanks
  • 12,644 posts
  • Location: East of San Antonio Texas

Posted August 21, 2011 - 08:19 PM

Thanks for posting all this great info you found on Brian Miller's site. It will help a lot of members...

#5 deere3332 OFFLINE  

deere3332
  • New Member
  • Member No: 11689
  • 0 Thanks
  • 4 posts
  • Location: williamston michigan

Posted September 25, 2012 - 06:18 PM

great stuff. Thanks!!!!!!!