My C-120 is smoking... All of the sudden!

[frankiefiredog 1]

So I'm cutting grass the other day, and I noticed the motor sounded a little different. I pulled it in the garage and shut her down. Let he cool off a bit. Checked the oil, and it was just above the "Add oil" line. Not empty, but it needed some. Went out and bought 2 quarts and added a quart to get it back to full. Fired the girl back up. In less than 10 minutes, the engine started burning oil BAD. Just like that. As sudden as could be. So I shut it down and checked the dipstick again. Oil level was fine. Grass had to be cut, and she sounded better, so I finished the front yard. Pull her back in the garage, and by the time I had her parked, I could barely see! That's a lot of smoke! So today I go out and check the oil. She's about a half quart low!!!! I add the oil in, and cut the grass again. She runs great. Sounds great. Power is there. Cuts fine. But still smoking like a diesel! If you remember my introduction a couple of months ago, this is my dads WH that he passed down to me. I grew up with this tractor and it's important that I keep it running well and cutting grass! I can do just about anything with this thing EXCEPT tear apart the motor. Never tried. I have some confidence. I could rebuild the rest of that tractor blindfolded. I just never messed with the motor. My father rebuilt the motor himself back in 1996. Between 1996 and him giving it to me this spring, it sat around a LOT. I used it many times before this smoke problem started. This is a Tecumseh 12HP engine. The original that came on the C-120 in 1975. I know many of you hate the Tec, but it's what I have to work with. I'll take any advice you have. I have not touched the motor other than adding oil. If you think I should just take it somewhere and have someone else fix it, I will. Your opinions and advice are very much appreciated. Thanks. Help me get this old girl back and running right.

Dave

Lagrange, Ohio

[frankiefiredog 1]

I forgot to add that the tip of the exhaust pipe seems wet now. Like there is maybe some unburnt oil on it. Is this blow-by? Like I said, I don't know motors real well, Just trying to see if there is maybe a cut and dry problem here. Thanks again!

Dave

Lagrange, Ohio

[frankiefiredog 1]

No response? I know there are some really sharp people on this site that can point me in the right direction.

:D

[MaineDad 87]

Dave,

One easy thing to try is to remove the head and check the top of the engine. You can see the exhaust and intake valves, plus you will be able to check the piston and see how much carbon buildup you have. Any Napa store will have a replacement head gasket when you put the head back on. Just make sure you keep track of each head bolt and which one went where...

[jimbotelho 1]

Maybe a broken piston ring?

[stevasaurus 23,247]

Dave...you will get guys that know in here in the next couple of days...I'm sure. I would not be afraid to tear it down, but Techy parts may be a problem. I would check on availability of parts first. One thing I would say...do not use it anymore. You could end up making it junk. My guess is a valve guide broke or maybe the piston rings. Those would be fixable...easy...but if you run it and gouge the cylinder or jam a broken piece through the block.

Maybe a member near you has an engine you can buy or use while you look into this one. Hope that helps. :USA:

[frankiefiredog 1]

Ok. Sounds easy enough. My dad was really good about keeping EVERYTHING nice and organized when it comes to manuals. I have all of the books. When I get home tonight, I'll look up the head gasket and call NAPA. Once I know they have one, I'll go get it. Then I'll start by taking off the head and snapping a few pics of what I see. I'll post them here for you guys to take a look. I won't run it anymore until I get it fixed. Thanks!

Dave

Lagrange, Ohio

[piecrazy4 0]

:D

[rickv1957 73]

All though the tecumseh parts are alittle hard to find,a freshened up motor will last many years,Rick

[oldandred 15]

No response? I know there are some really sharp people on this site that can point me in the right direction.

PPPPPPPSSSSSSSSSSSSS we are all sleeping and getting ready for the WHS :D

[tbbahner 28]

Dave,

Not an expert by any means so hope someone corrects me if I give you the wrong info. Tec engines are kind of a different breed to work on so they get a bad rap. I've had several, and they pack a lot of punch into a small package. The little 6hp Tecs are a good example. You really got to watch the oil in them.

Like others said, the only way to tell is to rip it apart. Sounds like it could be broken ring/s, worn piston, cylinder bore, valve guides, etc. Never been into the valve area much except to lap, and adjust. Sometimes the cause is obvious once you tear it apart. Sometimes not. Its been quite a while since I went through an old HH100 but the Tec manual was pretty good in explaining things. When you reassemble, pay close attention to the crank shaft end play. They knock like a lose rod if not set up correctly.

There's a lot of really good technicians around here that can steer you right. Don't be afeared, its broke anyway and you can always take it to someone thats already been there.

Tom B

[frankiefiredog 1]

ok guys... head is off. gasket just came right off. looks really good. the piston on the other hand.... ill let you guys decide. also the plug was pretty black and fouled. the valves were just as black. the outside of the engine may actually be cleaner than the inside. cyl is bright and super smooth. motor turns easily and the valves move. here are the pics of my hh120. thanks so far.

[Buzz 502]

Dave, not sure if you have the Tecumseh manual but here it is thanks to MTF:

http://www.mytractorforum.com/images/refer...o18castiron.pdf

Good luck.

[MaineDad 87]

Dave,

Does the cylinder have any movement side to side?

[rueger-99 0]

Is your crankcase breather working..? The side of the motor looks wet with oil in the picture.....A non-working breather will pressurize the crankcase and blow oil past the valve guides, rings and motor gaskets. If the motor starts and runs clean for a while before it starts smoking I would also check to make sure it has good airflow over it and its not overheating, though it looks clean in the pics, i dont know if you cleaned it up.

Good luck :D

[frankiefiredog 1]

there is no play in the cyl. i didnt clean up the motor at all. there is quite a bit of oil on the front of the motor below the carb. not sure how long its been there. is the breather the rubber tube that hangs below the carb? i suppose i need to read that tec manual. how do i get rid off all that carbon off the piston, valves, and head? thanks. you guys are teaching me to teach myself as i go.

:D

[ChevelleSSLS6 0]

there is no play in the cyl. i didnt clean up the motor at all. there is quite a bit of oil on the front of the motor below the carb. not sure how long its been there. is the breather the rubber tube that hangs below the carb? i suppose i need to read that tec manual. how do i get rid off all that carbon off the piston, valves, and head? thanks. you guys are teaching me to teach myself as i go.

use a light duty paint scraper with the flexible blade. You dont' want to gouge the metal surfaces.

Also a trick for better airflow into the cylinder: take a dremel tool and lightly round the top edge of the cylinder at the valve area. Be SURE to remove all particles. A shop rag (clean) preferably with some oil (its sticky and crap will stick to it) works well.

[rickv1957 73]

I would go ahead and pull piston out and check it,if OK install a new set of rings while you have it opened up,Rick

[stevasaurus 23,247]

The valves look like they are not burnt, but you have some build up that looks like it has been going on for awhile. Did you do a compression test before you tore it apart? I remember you said it ran good when you put oil back in it. If not...you can put some 10w-30 in the cylinder after you clean it to see if the oil runs right through or holds in the cylinder for a little bit. Not necessarily conclusive for bad rings but if it runs right through...guess what. I am leaning toward the breather after looking at the pictures and seeing what looks like fresh oil on the side. I hope others chime in here...I'm good, but I'm not great on this. One thing...it looks fixable. :USA:

[frankiefiredog 1]

I would go ahead and pull piston out and check it,if OK install a new set of rings while you have it opened up,Rick

This is really testing my comfort zone. Pulling the piston out? We haven't even met yet...

I'll see what I can do. Never gone this far in to an engine before. Thank you all for your help so far.

***EDIT***

I have NOT run a compression test. I do not know how, or even if I have the proper tools to do so. I assume it's something you do through the spark plug assembly.

Dave

Lagrange, Ohio

[ChevelleSSLS6 0]

I would go ahead and pull piston out and check it,if OK install a new set of rings while you have it opened up,Rick

This is really testing my comfort zone. Pulling the piston out? We haven't even met yet...

I'll see what I can do. Never gone this far in to an engine before. Thank you all for your help so far.

Dave

Lagrange, Ohio

Theres a first time for everything. I learned on mowers I dragged home. Dad loved me for that (NOT). Mom was ok so long as she couldn't see them (stashed behind the garage). :D

[stevasaurus 23,247]

Dave...just wondering what you found... :D

[gwgdog66 23]

Dave,

Sounds like you have received some good advice so far. Had this been a Kohler, I would suggest checking the fuel pump, and making sure fuel isn't getting in the cylinder and diluting the oil, causing the heavy smoke and use of the thinned out oil..

This being an HH120, I can't offer anything helpful from experience. Is the fuel pump on the engine mounted to the crankcase, or is it a vacuum type?

[frankiefiredog 1]

Just got back from vacation and had a buddy look the motor over. He's worried about findind parts and costs involved to have it bored for larger rings. He feels an engine that's 35 years old should not get original rings. Opinions on this? According to the manual, and what I found, the breather seems to be ok. So it looks like rings. My buddy doesn't want to touch this project and the local mower shop quoted me about $400 for the job. The mower shop also recommended I maybe look for another motor that will fit. Either a rebuilt Tec or a Kohler. I just need this thing running to keep the grass cut. What says all of you? Thanks!

[rickv1957 73]

What will the local shop include for 400.00,Rick