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I have a 1973 Craftsman Surburban with a Tecumseh OH160 engine. The seat for the exhaust valve dropped out of the head. I have another good head. I need to exchange the steel exhaust pipe from the bad head to the good head. Do any of you have any ideas on how to get these pipes out of the aluminum heads? Thanks for any help.
dana a

I would soak with PB Blaster for 24 hours and then slowly heat the head with a propane torch. Using a pipe wrench keep constant pressure on the pipe and it should come free.

as said, PB Blaster for 24 hours on the threads or Liquid Wrench. Iron/Steel rusts, and when it does it expands as it absorbs O2 molecules. A true penetrating oil will have chemicals in it that cause the red rust to change to black rust, which has a smaller molecule size. As the rust shrinks it will help pull the penetrating oil in. Heating the head will cause it to expand and make the removal easier. If that fails get it hotter.

Red Rust = Fe2O3(4 to 6 H20)
Black rust ( actually called mill scale because it forms at higher temperatures ) FeO
FeO is much much stronger than Fe2O3 and a lot more chemically stable.
This is why black iron does not rust very quickly
Black oxide ( technically it is not rust ) is also very porous which is why it takes up an oil film so well to resist rusting.
Basic rules of entropy
That which is formed and stable at high temperatures is very stable at room temperature
Heating the head drives off the water ( which is what makes red rust flakey ) and provides entry cavities for the penetrant / solvent
And because Al & Fe expand at different rates mechanically fractures the bond between the Al2O3 ( aluminium oxide ) & and the Fe2O3 (rust )
In both the cases they jointly hold onto the H20 and some times can even share them
And FWIW the white fluffly oxide on aluminium in damp environments is Al2O3(6H2O)

penetrants / rust release agents that leave a black finish are Phosphates not oxides
And this includes all of the solutions like Rust Buster / Ferro Pro etc

dana a said:

I have a 1973 Craftsman Surburban with a Tecumseh OH160 engine. The seat for the exhaust valve dropped out of the head. I have another good head. I need to exchange the steel exhaust pipe from the bad head to the good head. Do any of you have any ideas on how to get these pipes out of the aluminum heads? Thanks for any help.
dana a

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I have a STRUCK tractor on the shop right now with a OH140 on it and i have a 70's Sears suburban in the barn with a OH160 i want to restore. I have a HH120 on a Sears ST12 i blow snow with and a VH100 on an old Bunton walk behind. I really like the old cast iron tecumseh stuff.

Hammermechanicman said:

I have a STRUCK tractor on the shop right now with a OH140 on it and i have a 70's Sears suburban in the barn with a OH160 i want to restore. I have a HH120 on a Sears ST12 i blow snow with and a VH100 on an old Bunton walk behind. I really like the old cast iron tecumseh stuff.

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I've taken a lot of small engines apart. I was really impressed with this OH160. It ran for 49 years till it dropped the exhaust valve seat. I think it's really built strong and I've never seen a small engine with tapered roller bearings on the crank shaft. My OH160 has 2 counter weight gears in the bottom of it. I also have a parts engine and it doesn't have the counter weights. I was told I could just leave the weights out. I figured with the piston at top dead center that should keep the engine balanced if slid back together standing upright. What do you all think?

It will run without the weights.
Yeah, the things were built like tanks. As long as you don't over rev them they last forever.

Hammermechanicman said:

It will run without the weights.
Yeah, the things were built like tanks. As long as you don't over rev them they last forever.

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Will it run just as well without the weights as with? Did you ever put one back together with the weights?

The engine will vibrate more without the weights i assume. I did a Frankenmotor to save a blown HH120. Used crank rod and piston from an engine that was supposed to be a Dyna-Static balanced engine and used them in one without. None of my engines have those weights. What is the complete engine code off the engine with the weights? Like OH160-1700xxx

THE ONLY NUMBERS on the engine are the Sears numbers. There are no Tecumseh numbers. I started the first sentence a few days ago and never posted it and was surprised to see it still there. I was able to get the pipe out of the damaged head and it brought the aluminum threads with it. The good head has a street elbow and I'm going to leave it. I have the engine put back together and on the tractor and started it today. It runs pretty good but the carb needs some adjusting. Then I noticed the vent in the top of the valve cover was puking oil out and the needle jet thing on the bottom of the carb bowl was leaking gas. I took the needle thing out and saw there was no packing to prevent leaking. I assume there is supposed to be something to prevent gas from leaking so I found a small "O" ring and put it on the needle. Next I took that vent thing off the top of the valve cover and cleaned it in gasoline and blew it dry. I thought maybe that valve in the vent may have had something keeping it open. I sucked on the hose and there was no resistance but when I blew into the hose there was resistance but air did pass thru it. I didn't think any air should go thru it. Is that valve supposed to keep the airway completely closed on the up stroke of the piston or just partially closed? I took it outside and started it and the gas leak was fixed and there wasn't any oil coming out of the vent, but I didn't run it as long as I did the first time. I'll try it again tomorrow.
I think I read that the carb screws are both supposed to be set at 1 1/2 turns out from closed to get it started. I'm not very good at tuning a carb. Can anyone give me some pointers on how to do it?

What is the 143. number. Might be able cross reference it to the Tecumseh engine model and spec.

StarTech said:

What is the 143. number. Might be able cross reference it to the Tecumseh engine model and spec.

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With you knowing it was a 143 number you have been playing with this stuff for a while. It is 143 640012 and serial # is 3166E.

dana a said:

With you knowing it was a 143 number you have been playing with this stuff for a while. It is 143 640012 and serial # is 3166E.

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Maybe...The only problem is I came in as Tecumseh was going out of business so I got only limited knowledge on them.

143-640012 is listed as a Tecumseh OH160-170016.

I am going to assume you have the LMH carb on it. It has the large 4 bolt flange for the air cleaner. It came 2 ways. One with a fixed jet bowl nut and one with an adjustable main jet bowl nut. If adjustable run engine at high idle and turn needle in till engine starts to stumble lean then turn out till stumbles rich then set needle half way between the 2 settings. If engine doesn't accelerate smoothly from low idle to high idle turn screw out about 1/4 turn more. If you blow oil out the breather hose check the drain holes in the breather are not clogged. If i get time i will get some pics of the breather of my OH140. Does it have the fuel pump that screws into the carb body?

Just finished this last week. Had to clean and Redcoat the tank, replace fuel line, rebuild fuel pump, clean and rebuild carb. It has an OH160 in it

Hammermechanicman said:

I am going to assume you have the LMH carb on it. It has the large 4 bolt flange for the air cleaner. It came 2 ways. One with a fixed jet bowl nut and one with an adjustable main jet bowl nut. If adjustable run engine at high idle and turn needle in till engine starts to stumble lean then turn out till stumbles rich then set needle half way between the 2 settings. If engine doesn't accelerate smoothly from low idle to high idle turn screw out about 1/4 turn more. If you blow oil out the breather hose check the drain holes in the breather are not clogged. If i get time i will get some pics of the breather of my OH140. Does it have the fuel pump that screws into the carb body?

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My carb says Walbro on it and it has the adjustable main jet bowl nut and yes the fuel pump was screwed into the carb. It wasn't working right and I'd had it apart a couple time so I just took it off and let gravity pump the gas . When the fuel level gets down a ways and I'm going up a hill sometime it runs out of gas. Then I blow in the gas tank and fill the bowl and get off the hill. I didn't see any drain holes in the breather. I started it up a couple days ago and it ran OK and wasn't blowing out any oil. I moved the log splitter to the porch on the garage and after unhooking the splitter I noticed it was puking oil out the breather tube again. I had that happen with a flat head Briggs once. I made a gasket for the breather and those little holes were covered by the gasket and it puked oil. After some trial and error I cut out where the holes were and the puking stopped. I have a new gasket on the OH160 breather now and it is different than the one that was on it and I think that old gasket was one I made years ago after replacing the head gasket. I had bought some OH160 parts off ebay a while back and a gasket kit was with the parts and it was for more than one size engine and the breather gasket was thicker, about 1/8 inch, and covered a smaller area.
That engine on that Struck Big Job looks like mine. I assume it has the rectangular valve cover with 2 screws holding the breather and valve cover to the head. Where are those drain hole in that breather? I took pictures but I can't figure out how to reduce the size of the pictures to meet the attachment requirements.

The guy already picked up the Struck. I have a OH140 buried somewhere in the barn. If i get some time will aee if i can get a pic of the breather. The kit to rebuild the fuel pump is still available. I just did the one on the struck.

Here is the breather. It is different from the other ones i have seen. This one does not have the drain holes. There is a foam piece in the breather that acts as a precipitator to separate the oil out of the mist and then i assume it runs back into the engine off the sloped piece.

Hammermechanicman said:

View attachment 62495

Here is the breather. It is different from the other ones i have seen. This one does not have the drain holes. There is a foam piece in the breather that acts as a precipitator to separate the oil out of the mist and then i assume it runs back into the engine off the sloped piece.

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That is what my breather looks like. I blew in on the breather hose and it had some restriction to it. I thought it probably should have had more restriction. I have had the breather mounted with the drain going both ways so I didn't think that would make a difference. It had been on reversed of the original position for several years and never blew oil out.