12hp OHV Tecumseh on Craftsman II

arpcentralone · 05-07-2009, 02:43 PM

Hi all, I have a Craftsman, number 917.254245, and the engine on it is a 12hp OHV Tecumseh, 120358X. That number is what Sears said, and after googling it, nothing useful came up. Here's the problem I'm having with this mower. It will crank, run, fast and slow, however, when throttled down to a near idle, it hiccups through the carb and blows a mist of gasoline. I have removed the carb and cleaned it thoroughly, new plug, oil change, taken off the head and relapped the valves, put it all back together again, and still the same problem, although it does run a little better now. Someone said it may be the crank/flywheel key bent, but i dunno. It runs mostly fine at a higher rpm, just at lower rpm's it gives me a little fit. Any ideas would be greatly appreciated. THanks!

Greg

**manic** · 05-07-2009, 09:34 PM

Check float level, check the float, a float can look fine but be filled with
gas, or gas soaked.

arpcentralone · 05-08-2009, 09:34 AM

okay, i checked the float, and needle, needle seat, everything is fine with it. It kind of acts like it misses at a low idle, and when it does, the governor moves, but it dosen't miss because of an ignition issue, that's been checked and checked again. The only thing I could imagine is the timing might be off slightly, or the carb is still messed up. Also, does anyone know the valve lash setting for this engine? I set the intake at about .009 and the exhaust at about .014.

k2skier · 05-08-2009, 10:18 AM

On the shroud of the engine there should be a 143. ------ number, that would help. The carb will most likely need to be boiled out and a new kit installed. Most Tecumseh valves set at .004 on both vales.

arpcentralone · 05-08-2009, 10:41 AM

Thanks for that info. The numbers on the shroud read:
143 386012 SER8201R

This engine shroud is marked as a "Craftsman" but I know better. Dang Craftsman for putting their name on other manufactures stuff.

arpcentralone · 05-08-2009, 10:51 AM

Okay, after some searching, this is an OMV120 Tecumseh. I cannot find a new carb on ebay, so I guess I will rebuild this one. Just don't wanna do it and it not fix the problem. To k2skier, what do you mean "boiled out"? I disassembled the carb and soaked it in safety kleen for 24hrs, then cleaned every piece and hole in the thing. Sprayed carb cleaner through each hole to make sure it wasn't clogged. Maybe it is the float, it's got a metal float. I cannot find a replacement float anywhere.

Thanks!

k2skier · 05-11-2009, 11:35 AM

Sears still has them for $91.05 +S&H, my price is $85.14 (+S&H of course). PM me if you would like to order one, I can do VISA over the phone.

Joezilla64 · 05-16-2009, 11:18 AM

Here is the manual for your engine.

http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_4-Cycle_OHV_Engines_Service_Information.pdf

Make sure the idle is not too low. There is a idle fuel mixture screw under the idle adjustment screw on the carb. That fixed the idling problem on my engine.

There is also a tube that is plugged into the inside of the carb and sticks out into the intake. You need this for the carb to work right.

05-07-2009, 02:43 PM	#1 (permalink)
arpcentralone Registered User Join Date: May 2009 Posts: 4 OS: Vista 64bit	12hp OHV Tecumseh on Craftsman II Hi all, I have a Craftsman, number 917.254245, and the engine on it is a 12hp OHV Tecumseh, 120358X. That number is what Sears said, and after googling it, nothing useful came up. Here's the problem I'm having with this mower. It will crank, run, fast and slow, however, when throttled down to a near idle, it hiccups through the carb and blows a mist of gasoline. I have removed the carb and cleaned it thoroughly, new plug, oil change, taken off the head and relapped the valves, put it all back together again, and still the same problem, although it does run a little better now. Someone said it may be the crank/flywheel key bent, but i dunno. It runs mostly fine at a higher rpm, just at lower rpm's it gives me a little fit. Any ideas would be greatly appreciated. THanks! Greg

05-07-2009, 09:34 PM	#2 (permalink)
manic Mod Hardware Team Join Date: Aug 2005 Location: Florida Posts: 5,246 OS: xp	Re: 12hp OHV Tecumseh on Craftsman II Check float level, check the float, a float can look fine but be filled with gas, or gas soaked. __________________

05-08-2009, 09:34 AM	#3 (permalink)
arpcentralone Registered User Join Date: May 2009 Posts: 4 OS: Vista 64bit	Re: 12hp OHV Tecumseh on Craftsman II okay, i checked the float, and needle, needle seat, everything is fine with it. It kind of acts like it misses at a low idle, and when it does, the governor moves, but it dosen't miss because of an ignition issue, that's been checked and checked again. The only thing I could imagine is the timing might be off slightly, or the carb is still messed up. Also, does anyone know the valve lash setting for this engine? I set the intake at about .009 and the exhaust at about .014.

05-08-2009, 10:18 AM	#4 (permalink)
k2skier Registered User Join Date: Sep 2008 Location: Oregon Posts: 313 OS: XP Home-SP3 My System	Re: 12hp OHV Tecumseh on Craftsman II On the shroud of the engine there should be a 143. ------ number, that would help. The carb will most likely need to be boiled out and a new kit installed. Most Tecumseh valves set at .004 on both vales.

05-08-2009, 10:41 AM	#5 (permalink)
arpcentralone Registered User Join Date: May 2009 Posts: 4 OS: Vista 64bit	Re: 12hp OHV Tecumseh on Craftsman II Thanks for that info. The numbers on the shroud read: 143 386012 SER8201R This engine shroud is marked as a "Craftsman" but I know better. Dang Craftsman for putting their name on other manufactures stuff.

05-08-2009, 10:51 AM	#6 (permalink)
arpcentralone Registered User Join Date: May 2009 Posts: 4 OS: Vista 64bit	Re: 12hp OHV Tecumseh on Craftsman II Okay, after some searching, this is an OMV120 Tecumseh. I cannot find a new carb on ebay, so I guess I will rebuild this one. Just don't wanna do it and it not fix the problem. To k2skier, what do you mean "boiled out"? I disassembled the carb and soaked it in safety kleen for 24hrs, then cleaned every piece and hole in the thing. Sprayed carb cleaner through each hole to make sure it wasn't clogged. Maybe it is the float, it's got a metal float. I cannot find a replacement float anywhere. Thanks!

05-11-2009, 11:35 AM	#7 (permalink)
k2skier Registered User Join Date: Sep 2008 Location: Oregon Posts: 313 OS: XP Home-SP3 My System	Re: 12hp OHV Tecumseh on Craftsman II Sears still has them for $91.05 +S&H, my price is $85.14 (+S&H of course). PM me if you would like to order one, I can do VISA over the phone.

05-16-2009, 11:18 AM	#8 (permalink)
Joezilla64 Registered User Join Date: May 2009 Posts: 2 OS: xp	Re: 12hp OHV Tecumseh on Craftsman II Here is the manual for your engine. http://www.smallenginesuppliers.com/html/engine-specs/tecumseh/Tecumseh_4-Cycle_OHV_Engines_Service_Information.pdf Make sure the idle is not too low. There is a idle fuel mixture screw under the idle adjustment screw on the carb. That fixed the idling problem on my engine. There is also a tube that is plugged into the inside of the carb and sticks out into the intake. You need this for the carb to work right.