CV 740 kohler engine want start after we replaced short block

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DTanner0512

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  • / CV 740 kohler engine want start after we replaced short block
We bought a short block for mower put the heads on it I tried cam both ways because it wouldn't crank so I thought it was out of time so I took motor out open it up timed it by the marks but I'm blowing out of intake and sucking out of exhaust what's wrong? I've been a mechanic for 30 years and have done all my small engine repair but I'm confused please help
 
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reynoldston

reynoldston

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  • / CV 740 kohler engine want start after we replaced short block
DTanner0512 said:
We bought a short block for mower put the heads on it I tried cam both ways because it wouldn't crank so I thought it was out of time so I took motor out open it up timed it by the marks but I'm blowing out of intake and sucking out of exhaust what's wrong? I've been a mechanic for 30 years and have done all my small engine repair but I'm confused please help
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You got me confused. Doesn't a short block come with a camshaft, lifters, crankshaft, and complete heads?? What do you mean by trying the cam both ways? Yes I agree you install the camshaft by the timing marks on the crankshaft gear and camshaft gear by putting them together. Some engines with overhead camshafts use a timing chain but not on that engine. Did you use the old lifters? Because if you did you should bleed them down before installing them. Are you installing a engine block and or a short block?
 
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DTanner0512

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  • / CV 740 kohler engine want start after we replaced short block
reynoldston said:
You got me confused. Doesn't a short block come with a camshaft, lifters, crankshaft, and complete heads?? What do you mean by trying the cam both ways? Yes I agree you install the camshaft by the timing marks on the crankshaft gear and camshaft gear by putting them together. Some engines with overhead camshafts use a timing chain but not on that engine. Did you use the old lifters? Because if you did you should bleed them down before installing them. Are you installing a engine block and or a short block?
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Yes I did install short block and did bleed lifters I can take rockers off and have no blow by anywhere so no bent valve. What I mean by timing marks is crank makes two revolutions to the cam making one I've tried lining the marks up then I tried one revolution with crank the cam mark was at top of motor took cam out lined them back up still have same problem blowing out of intake and sucking on the exhaust, could I possibly have wrong cam? Didn't start this job and old parts got throwed away. Can rotate motor counter clockwise and it will work like it's supposed too any suggestions
 
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DTanner0512

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  • / CV 740 kohler engine want start after we replaced short block
DTanner0512 said:
Yes I did install short block and did bleed lifters I can take rockers off and have no blow by anywhere so no bent valve. What I mean by timing marks is crank makes two revolutions to the cam making one I've tried lining the marks up then I tried one revolution with crank the cam mark was at top of motor took cam out lined them back up still have same problem blowing out of intake and sucking on the exhaust, could I possibly have wrong cam? Didn't start this job and old parts got throwed away. Can rotate motor counter clockwise and it will work like it's supposed too any suggestions
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Thanks I've already read it from front to back!
 
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DTanner0512

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  • / CV 740 kohler engine want start after we replaced short block
I didn't start this project I came into it because the other guy couldn't make it run. I came into this blind and behind someone else, they bought short block put heads on it and everything when he tried to crank the motor it would barely even turn with two batteries and battery charger hooked up to it. I took motor back out opened it up and found the shim on crank at the bottom of motor was to thick and was locking the motor up,so I ground shim and put it back and it turns fine now then I put motor back together from there I timed it up according to the timing marks on crank and cam but it will not start. It's blowing out the intake and sucking on the exhaust side but if I reverse it sucks on intake and blows out on exhaust what is wrong
 
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mechanic mark

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  • / CV 740 kohler engine want start after we replaced short block
Recheck timing marks on crankshaft & camshaft for alignment, also check push rod lengths making sure they are installed correctly, if same length exhaust push rod is almost twice as heavy as intake, also check gear on crankshaft for spinning, or moving, pressed on fit should not move.
 
reynoldston

reynoldston

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  • / CV 740 kohler engine want start after we replaced short block
mechanic mark said:
, also check push rod lengths making sure they are installed correctly, if same length exhaust push rod is almost twice as heavy as intake, .
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On that engine with all the push rods in my hand I really don't see a different in weight or length. I know the service manual says not to mix them up in which I don't. But some times when someone else takes things apart how do you tell the different, I just don't see it?? Also they both have the same part number? I just went through this a couple of weeks ago on a command CH engine or is the command CV different?
 
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