Kohler Courage 15 SV740 valve guides

charlieboy

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Hi guys your help would be much appreciated having no end of problems with this engine but my query at the moment is can anyone tell me the height of the valve guide measured from the spring side of the head ,from top of guide to head, I think one of my guides has moved as the exhaust guide is much higher out from head than inlet ,before I drive this back in would like to make sure of heights,Thanks all.
 

bertsmobile1

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Don't have the measurements but I can tell you they should both be identical heights so what you suspect is correct.
Guides are not a listed service part for most Kohlers.
You may be able to stake it in or get an oversize one made if you can machine or know a friendly machinist.

Now the one & only reason for a guide shifting is gross over heating of the head so that will need to be fixed otherwise you will be doing this all over again.
 

charlieboy

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Hi thanks for reply,just about to call the men in the white coats for this one, started off usual problem ,went to start ,turned 1/2 revolution then stuck,long story short solenoid valve coil O/C, fitted tap in fuel line, did oil change all ok,now latest prob' is runs for 30 mins cutting,the acts like its got fuel starvation,whack open choke and it runs at fairly high revs for about another 5/10mins ok,the just dies,wont restart, leave it for 25/30 mins starts ok and runs again for 30mins, ok so far done:- carb,fuel filter,cleaned out tank and run with no cap on,new fuel lines,new plug,new coil assbly,pulled head and checked valve seats (lapped in ) ,blown out all fins nooks and cranny's with air line,run without hood on to see if its heat related,disconnected all safety switches/bypassed, taken off exhaust and checked for blockages/run with no exhaust, only odd thing I have noticed is that exhaust valve guide is higher out of top of head than inlet one,tired tapping it to see if its loose but not,so before my wife calls the men in white coats can anyone offer suggestions PLEASE
 

bertsmobile1

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If the guide is higher in the head than it should be, then the valve that runs in that guide can not open fully so the engine will run badly.
As this is an overheating problem, it will get worse when the engine gets hotter which makes the loose valve looser.
If you can move the guide, after removing the valves & springs with a tap while cold then the head is worn beyond repair.
Like bearings, guides are chilled then pressed into a hot head.

As you have replaced so many pets it is now very difficult to make a diagnosis as any of the parts you have replaced may have been installed incorrectly or faulty themselves.

The only suggestion I could make is to replace the head.
Should be plenty of them available from mower repair shopr ( not glass fronts, real repair shops as that engine had a problem that used to cause the block to crack down near the exhaust cam.
 

charlieboy

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Hi all thanks for replies, had some time spare today so pulled valve cover off and valve springs and checked height difference of valve guides,exhaust guide was about 1/4 higher in the head than inlet,so put a long reach 7mm socket over it and drifted in back down to the same height ,peened the metal around it in and put it all back together ,set valve clearances and fitted valve cover,fuelled it up and just run it for about 1 1/2 hrs cutting grass and it didn't miss a beat ( 35 min was usual time before it played up ) ,so that has cured that ,dont know for how long but will keep my eyes open for 2nd hand head but not very common find here in the UK,again thanks for your help guys much appreciated.
 

bertsmobile1

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Hi all thanks for replies, had some time spare today so pulled valve cover off and valve springs and checked height difference of valve guides,exhaust guide was about 1/4 higher in the head than inlet,so put a long reach 7mm socket over it and drifted in back down to the same height ,peened the metal around it in and put it all back together ,set valve clearances and fitted valve cover,fuelled it up and just run it for about 1 1/2 hrs cutting grass and it didn't miss a beat ( 35 min was usual time before it played up ) ,so that has cured that ,dont know for how long but will keep my eyes open for 2nd hand head but not very common find here in the UK,again thanks for your help guys much appreciated.

Ask around small mower repair shops, good excuse for a drive in the country, shocking time of the year to stop at a village pub for a pint, better make that a 1/2 pint as you have to drive home again.
That engine had a problem which caused a lot of them to crack the crankcase ans as small shops never throw good parts out there should be a few good heads kicking around.
 
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