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Hi guys Im new to this site. I just rebuilt my HH120 Tecumseh its on a 1966 sears suburban. Its was board .10 over I took it appart and saw the crosshatches in the cylinder. It looked great ,no ridge at the top. So I ran the hone through it ,bought a NOS set of tecumseh .10 over ring set ,checked ring gap all was good.Put it together and it runs great , but i noticed oil all over the front of the tractor.I can feel just a slight little puff of air from the breather tube. When I run it for 30/45 min I start seeing oil on the tractor???. The piston was in great shape ,thats why I cant figure out why so much oil vapor?? Anyone have an idea whats going on?? Is it due to the rings not beeing seated yet ?? Thanks for your help. Dan

I hope that you cleaned the block with hot soapy water after honing the cylinder, otherwise the grit will stay in the crosshatch grooves and wipe out a set of rings as well as hope the cylinder within a couple hours of startup.

Even if the rings haven't seated yet, that still sounds a little excessive blowby.

Thanks Ilengine, Yes I cleaned block after the cylinder work was done. I think I solved the problem,I noticed tha the breather cover was on with the tube at the lower righthand corner of the cover . I took it off and turned it to where the tube is at the top lefthand corner of the cover .Cut grass for an hour, no oil on the front of the tractor...:confused2: All is good so far..

Thanx for posting the fix, most people don't.

d10dano said:

Hi guys Im new to this site. I just rebuilt my HH120 Tecumseh its on a 1966 sears suburban. Its was board .10 over I took it appart and saw the crosshatches in the cylinder. It looked great ,no ridge at the top. So I ran the hone through it ,bought a NOS set of tecumseh .10 over ring set ,checked ring gap all was good.Put it together and it runs great , but i noticed oil all over the front of the tractor.I can feel just a slight little puff of air from the breather tube. When I run it for 30/45 min I start seeing oil on the tractor???. The piston was in great shape ,thats why I cant figure out why so much oil vapor?? Anyone have an idea whats going on?? Is it due to the rings not beeing seated yet ?? Thanks for your help. Dan

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I am stumped or maybe didn't understand what you wrote.
You said "I took it appart and saw the crosshatches in the cylinder. It looked great ,no ridge at the top So I ran the hone through it."
My question is,, If you saw the crosshatch, and there was no ridge at the top, why did you "then" run a hone in the cyl?
You "might" have altered the necessary cross hatch to a point that the oil isn't spreading around in the cylinder and will "quickly" cause uneven wear. A newly rebuilt engine needs to be broken in so the rings seat. If the critical cross hatch has been ruined, you will get blow-by which is "excessive crankcase pressure" caused by the compression leaking through the poorly sealed rings.

Just because part of the cross hatch is still there doesn't mean that the cylinder walls are not glazed. need to remove the glaze so the new rings will seat, unless using chrome rings, then don't hone. the chrome rings will wear into the cylinder.

ILENGINE said:

Just because part of the cross hatch is still there doesn't mean that the cylinder walls are not glazed. need to remove the glaze so the new rings will seat, unless using chrome rings, then don't hone. the chrome rings will wear into the cylinder.

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Yes but it was stated that the engine was just bored .010 over which would include a fresh cross hatch which is critical. Actually with chrome rings, it is the "cylinder" that wears/seats to the rings, not the other way around, because the cylinder is softer than hard chrome rings making the cross hatch even "more" critical for even oil distribution around the cylinder.

99% of all the small 2-stroke engines have their cylinder hard chrome plated (or nikicell) but not the rings. Once you see that plating worn off, you might as well trash that cylinder.

edit:
I re read your post " the chrome rings will wear into the cylinder." and yes that could be taken either way as the "cylinder" taking the wear/break in

chance123 said:

Yes but it was stated that the engine was just bored .010 over which would include a fresh cross hatch which is critical. Actually with chrome rings, it is the "cylinder" that wears/seats to the rings, not the other way around, because the cylinder is softer than hard chrome rings making the cross hatch even "more" critical for even oil distribution around the cylinder.

99% of all the small 2-stroke engines have their cylinder hard chrome plated (or nikicell) but not the rings. Once you see that plating worn off, you might as well trash that cylinder.

edit:
I re read your post " the chrome rings will wear into the cylinder." and yes that could be taken either way as the "cylinder" taking the wear/break in

Click to expand...

That is what I meant. The chrome rings will wear the cylinder to the shape of the rings, but the rings will wear a little to.

chance123 said:

Yes but it was stated that the engine was just bored .010 over which would include a fresh cross hatch which is critical. Actually with chrome rings, it is the "cylinder" that wears/seats to the rings, not the other way around, because the cylinder is softer than hard chrome rings making the cross hatch even "more" critical for even oil distribution around the cylinder.

99% of all the small 2-stroke engines have their cylinder hard chrome plated (or nikicell) but not the rings. Once you see that plating worn off, you might as well trash that cylinder.

edit:
I re read your post " the chrome rings will wear into the cylinder." and yes that could be taken either way as the "cylinder" taking the wear/break in

Click to expand...

That is what I meant. The chrome rings will wear the cylinder to the shape of the rings, but the rings will wear a little to.

Got a question???? You said you installed .010 oversize rings. Did you install a .010 oversize piston? I hope so, because without it your rings aren't going to last long, too much play.

Wow,thanks for the response guys!!. Ok heres what I did I bought this 1966 sears suburban it has the tecumseh HH120. The seller said it ran but was blowing oil out the carb... So I bought it had it shipped to joplin,when I got the tractor I didnt even try to start it . Ijust tore it down to restore it,I took engine off the tractor then disassembled it.when I got it appart I saw the ..10 stamped it the top of the piston.So I knew that it was board out .Pulled piston out and saw crosshatches from what I thought was the machine bore work.They were visable but kind of worn.Thats why I ran the hone through just to deglaze the cylinder.The rings I bought are NOS .10 over sized to match the .10 over piston. The rings are NOS Tecumseh rings .I have another suburban tractor with the hh100 that I rebuilt only I just honed it .I put new standard size rings in it and it ran great for 8 yrs before it started smoking a little.Anyway back to the HH120,there was no oil in the carb as the seller stated . I could tell just by looking at it that it was probably a cracked compression ring.But the rings were ok, no cracks . I cleaned up the piston with 3M scotch Brite.I might also state that I took all the engine parts and the block to work and cleaned them in our parts washer.I work at peterbilt of Joplin ,so I have accsess to some equipment to clean engine parts LOL .I totaly understand what can cause blow by,I just couldnt understand why all the oil on the front of the tractor..I knew I put everything together correctly.I ran the tractor for an hour yesterday after I turned breather cover around as I stated in past thread.All is good no oil on tractor or side of engine block.Put my finger on the breather tube just feel a sight little puff of air , no smoke or oil vapor.

Now we have the entire story to what has been done, and why.