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Kohler CH740 problems

#1

B

Big_kid

Hi, new guy here with engine problems.
i have a Kohler CH740 on my grasshopper 61”
I converted the electronic ignition to standard coils (Kohler kit) and all problems started after the swap.
the engine is low on power and exhaust is glowing red hot.
I remove the rockers and put air into the cylinder and air comes out intake valves. Nothing out exhaust side.
so I rip the engine apart and clean the heads good and install new intake valves. Lapped all 4 valves and Have good indication of a valve lapping job. Now with the heads back on (rockers off still) air comes out the intake valves even worse than before.
Also the flywheel key is NOT sheared. should I just slap it back together with the electronic ignition and see hat happens….


#2

B

bertsmobile1

Well either the kit you got was wrong or it is fitted wrong.
Please post the Kohler part number & the full engine number .
Those who can access the Kohler dealer network can then check that you have the right parts to start with .


#3

B

Big_kid

CH-740-0037
25 707 03-S

the instructions indicate The flat side goes out and it won’t fit the other way anyway. also, I lapped the valves until my shoulders fell off. It will hold water but not air. I’m gonna slap it back together and run it…Thanks for the help


#4

B

Big_kid

It looks like I need a flywheel too so I just put it back together and it runs like before. It just dosent run as smooth as my CV740 on my SCAG 61.

on my SCAG it would spit/sputter once in a wile so I swapped to regular coils and that thing purrs like kitten, just thought I’d do the same on my grasshopper. Oh well, another day maybe….


#5

S

slydog

Big_kid said:
Hi, new guy here with engine problems.
i have a Kohler CH740 on my grasshopper 61”
I converted the electronic ignition to standard coils (Kohler kit) and all problems started after the swap.
the engine is low on power and exhaust is glowing red hot.
I remove the rockers and put air into the cylinder and air comes out intake valves. Nothing out exhaust side.
so I rip the engine apart and clean the heads good and install new intake valves. Lapped all 4 valves and Have good indication of a valve lapping job. Now with the heads back on (rockers off still) air comes out the intake valves even worse than before.
Also the flywheel key is NOT sheared. should I just slap it back together with the electronic ignition and see hat happens….
Click to expand...
Not sure what is the problem with your 740, but retrofit coil kit has no impact on compression loss. The coils just pickup a magnetic field to provide spark for ignition. Nothing related to your valve seat issue. Closely inspect the head for micro cracks. This one needs a more in depth check to determine what is causing it. I'm at a loss also for the temp problem. I did the same coil changeover on my Scag CH740 and had no issues to date. Come back and let us know if and how this was resolved.


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