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Kohler CH730 Engine Blow by

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1.5K views 11 replies 5 participants last post by  ricky86  
L
#1 ·
I posted this on the tree equipment side but figured this might be a better place,

I've got a Rayco stump grinder with a Kohler CH730 engine. I noticed some oil coming from around the valve cover (Left side with the mechanical fuel pump attached). I opened the oil fill cap and noticed excessive blow by coming out. No smoke is coming out of the exhaust and the engine seems to be running normal. However after a while the valve cover seems to start spewing oil. Also, after shutting the engine down there continues to be a lot of pressure in the valve cover.

I replaced the breather filter/seal after noticing this. Anyone with experience with Kohler engines who could provide any tips on how to move forward would be great.
 
L
#4 ·
I replaced head gaskets today, still getting excessive pressure from oil fill cap. I also noticed oil coming from the top end where the governor is leaking. I am assuming its leaking through the seals because of the pressure.
 
R
#3 ·
The valve train is lubricated by oil mist also. Are you sure you’re seeing what you think?
Seen many failures with those pumps. Complete carnage to leaks.
Replace gaskets with oem and USE A TORQUE WRENCH.
That’s critical for correct o ring compression. Too much going on
under there. Electric or pulse pumps are an option after replacing the cover
Basically the pump flex and stress
may be part of your oil leak woes.
 
L
#5 ·
ricky86 said:
The valve train is lubricated by oil mist also. Are you sure you’re seeing what you think?
Seen many failures with those pumps. Complete carnage to leaks.
Replace gaskets with oem and USE A TORQUE WRENCH.
That’s critical for correct o ring compression. Too much going on
under there. Electric or pulse pumps are an option after replacing the cover
Basically the pump flex and stress
may be part of your oil leak woes.
Click to expand...
I replaced the head gasket today and it appears to still be leaking and still a lot of pressure. I am thinking its just leaking out of the pump (around the seals) because that was the path of least resistance. I torqued the bolts down for the valve cover that contains the fuel pump and now there is oil coming out from around the governor. I'm not really sure where the pressure is coming from. Keep in mind there is no smoke coming from the exhaust at all and engine believe it or not is running great.
 
R
#8 ·
It would clear things up in regard to wtf is going on.
If you do get one, unless it liquid filed, it’ll bounce
(guage) alot, but it should be towards vac side.
I have a very expensive one I never use.
I normally use a Harbor Freight fuelpump
combo vac/pressure tester
 
R
#9 ·
These small engines have very slight crankcase vac. Measures are in inches of water
not mercury. Keep that in mind.
A manmeter, old school homemade is just as accurate as a 400.00 Snap-On.
All depends on the graymatter content of user.
 
H
#10 ·
Pressure relief valve in correct?
 
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