Craftsman 917.28712 runs fine but white smoke

J

jlatenight

Member
Hey everybody, So I have a Craftsman 917.28712 riding mower, I think from 2007, that was sitting a while, but didn't see a ton of use. It starts fine, runs fine, idles fine, power is fine, didn't overfill the oil, air filter doesn't have oil in it.....but it tears through oil. It puffs white smoke out which comes and goes. It's not thick smoke, but sometimes it can be pretty heavy, and then it will stop for a while then smoke again. Sort of fades in and out. I did a head gasket, same thing, so I did it again with another gasket thinking I did it wrong, same thing. At this point I'm thinking bad piston rings? I read it could be a clogged breather tube too. Does that sound possible? Where do you guys and gals think I should go from here? Thanks!
 
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Official Craftsman 917287120 front-engine lawn tractor parts | Sears PartsDirect

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Post B&S Model xxxxxx, Type xxxx, Trim xx, Code xxxxxxx from engine please.
Perform a compression test on each cylinder. Auto parts stores rent them out & you will get a full return upon returning compression test kit. Please let us know how it goes, thanks, Mark
 
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B&S 31P977 0635 E1 070328ZD I did a compression test and it was 120psi The plug looked clean, oil around the threads. I did a leak down test and it was 60%. Noise coming our of the oil fill tube. I could hear noise coming out from the valve cover too (probably expected). So I guess it's piston rings? What do y'all think?
 

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Make sure Air Filter & Breather are clean & not obstructed. Have you ever removed Blower Housing topside of engine cover & cleaned engine cooling fins so engine can breathe, if not try this first. You may be surprised at the amount of crud you remove. Let us know how it goes, thanks, Mark
Your engine parts manual is posted above. Always use B&S OEM Parts.
Adjust valves with engine cold per specs. in Operators Manual.
 
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Hi Mark, I had the blower housing off, and besides some caked-on dust, there's no other obstructions. I took off the breather tube and it's clear. Air filter's fine. valve lash is set per spec. What's my next move? Thanks so much for the help, btw.
 
Did you lap the head and block gasket surfaces prior to installing the then new head gasket?

If not you left out a step in properly replacing a head gasket.
 
slomo said:
Did you lap the head and block gasket surfaces prior to installing the then new head gasket?

If not you left out a step in properly replacing a head gasket.
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I gently cleaned the surfaces of all the old gasket before I put the new one on. When I put the 2nd head gasket on, because I thought I did something wrong the first time since it was smoking exactly the same, I didn't see any damage, marks or discoloration on the old gasket. Honestly didn't on the first one I removed either. The leak-down test I did produced air noise from the oil fill tube. Cylinder at TDC. Could I have a stuck ring? I was going to try the seafoam treatment and see if that helps: pour in small amounts of seafoam a little at a time while it's running, and then enough to stall the engine. I wish I could soak the piston in seafoam for a while, but it's horizontal. I also bought some marvel mystery oil and thought I'd try that too.
 
jlatenight said:
The leak-down test I did produced air noise from the oil fill tube.
Click to expand...
Cold or hot test? Air leaking past the rings and valves.
jlatenight said:
Could I have a stuck ring?
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Possible.
jlatenight said:
I was going to try the seafoam treatment and see if that helps
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Don't expect anything on this.
jlatenight said:
I wish I could soak the piston in seafoam for a while, but it's horizontal.
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Dump the oil and gas. Then soak the rings at your leisure. This is a great winter project. Pull the head and soak away.
 
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