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Info that maybe usefull to kohler engine owners
After many years of using kohler in many pieces of equipment every day there are some issues with this engine that will cause constant break down
Engine type
command series v twin
horizontal crank
electric start
carb/EFI
18--30 hp
carb 18,20 25 27 30
EFI 26 28
B4 i list some info ,as good as the engines are i personally have changed all my machines to diesel . Kohler is not a commercial engine and should be approached with caution when used
The info is not to deface kohlers reputation but to present fact ..
Fact All the machine suppliers i have dealings with have traded away from kohler to a different gas engine
carb engines
air cleaner seal upgraded
Positive crank case ventilation system
cover plate gasket oil leak upgraded
cover plate to air cleaner tube upgraded [old unit cracked and let unfiltered dirt into engine
the reed valve under cover plate does not seal properly on the cast housing
the filter mesh degrades quickly [use mesh from oil filler cap chev 6cyl etc ]
cylinder heads
blown head gaskets , head bolts have been upgraded to head stud
earlier heads up been upgraded to oil drain passage was to close to combustion chamber causing blown head gasket
The head gaskets do not use raised seal areas
The combution chamber part of the gasket is smaller in diameter than the chamber . This creates a shelf for carbon to sit on . Causes engine run on after switch off
Valve train noisey and wear
Cam shafts are made of very soft material wears quickly
The lifters /followers also problematic soft depending on the brand kohler used
Many 1970-1990 cars had this issue also
Valve rocker retaining bolts pull out of head . Machine shop drill and install steel plug
VALVE covers and gaskets
the plastic type covers degrade after years of service ,leaks etc
The gasket material and style have changed
The hold down bolts are changed with different types of cover
INLET / EXHAUST manifolds --sealing to mounting faceand therefore leaks
problem the sealing face on the cylindrer heads is a as cast finish resulting in a very very narrow seal surface due to its very rounded profile. silicon sealant solves this by moulding to surface .
A number of different inlet manifold designs have been tried to solve this
A leak on the inlet causes running poorly eg vacumn spray with carby spray on joint area and if the running condition improves u have diagnosed the problem
A leak on the exhaust face will only be a big issue if u have EFI ,will give the oxygen sensor the wrong reading
Fuel pump mechanical type
The valve cover mounted type can fill the sump with fuel
Flywheel timing weights
screws come loose
fix with aftermarket screws and magnent
starter motor
Failure due to operating in dirty enviroment -the motor sucks in air via screen and looks for a exit point ,the starter motor area is therefore blasted /filled with dirt
Replace Nippon Denso type with Delco unit . Delco unit is far cheaper
Starter solenoid
The solenoid on the N. D. type starter is very bad in regarards to the contacts located internally. The area used is very small when compared to the area available . Very very common issue
There are other issues and i will list them a little later on
tomo
After many years of using kohler in many pieces of equipment every day there are some issues with this engine that will cause constant break down
Engine type
command series v twin
horizontal crank
electric start
carb/EFI
18--30 hp
carb 18,20 25 27 30
EFI 26 28
B4 i list some info ,as good as the engines are i personally have changed all my machines to diesel . Kohler is not a commercial engine and should be approached with caution when used
The info is not to deface kohlers reputation but to present fact ..
Fact All the machine suppliers i have dealings with have traded away from kohler to a different gas engine
carb engines
air cleaner seal upgraded
Positive crank case ventilation system
cover plate gasket oil leak upgraded
cover plate to air cleaner tube upgraded [old unit cracked and let unfiltered dirt into engine
the reed valve under cover plate does not seal properly on the cast housing
the filter mesh degrades quickly [use mesh from oil filler cap chev 6cyl etc ]
cylinder heads
blown head gaskets , head bolts have been upgraded to head stud
earlier heads up been upgraded to oil drain passage was to close to combustion chamber causing blown head gasket
The head gaskets do not use raised seal areas
The combution chamber part of the gasket is smaller in diameter than the chamber . This creates a shelf for carbon to sit on . Causes engine run on after switch off
Valve train noisey and wear
Cam shafts are made of very soft material wears quickly
The lifters /followers also problematic soft depending on the brand kohler used
Many 1970-1990 cars had this issue also
Valve rocker retaining bolts pull out of head . Machine shop drill and install steel plug
VALVE covers and gaskets
the plastic type covers degrade after years of service ,leaks etc
The gasket material and style have changed
The hold down bolts are changed with different types of cover
INLET / EXHAUST manifolds --sealing to mounting faceand therefore leaks
problem the sealing face on the cylindrer heads is a as cast finish resulting in a very very narrow seal surface due to its very rounded profile. silicon sealant solves this by moulding to surface .
A number of different inlet manifold designs have been tried to solve this
A leak on the inlet causes running poorly eg vacumn spray with carby spray on joint area and if the running condition improves u have diagnosed the problem
A leak on the exhaust face will only be a big issue if u have EFI ,will give the oxygen sensor the wrong reading
Fuel pump mechanical type
The valve cover mounted type can fill the sump with fuel
Flywheel timing weights
screws come loose
fix with aftermarket screws and magnent
starter motor
Failure due to operating in dirty enviroment -the motor sucks in air via screen and looks for a exit point ,the starter motor area is therefore blasted /filled with dirt
Replace Nippon Denso type with Delco unit . Delco unit is far cheaper
Starter solenoid
The solenoid on the N. D. type starter is very bad in regarards to the contacts located internally. The area used is very small when compared to the area available . Very very common issue
There are other issues and i will list them a little later on
tomo
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