Tecumseh OH160/Case 1816

   / Tecumseh OH160/Case 1816 #1  

robirot

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Sep 21, 2021
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Tractor
Case 1816
I've got a Case 1816b, with a Tecumseh OH160 engine in it, not 100% wich engine number it has since it got painted over heavily, would like not to pull it out, since everything in that loader is small as heck.

My problem is, that the engine is back firing out of the carburetor and always going high rpm, tuning the carburetor down, doesn't change anything, just that the engine dies off.
First idea was to test the intake valve, but the engine keeps pressure.
So propably it is a timing problem.

The engine got the original SSI ignition unit (#610906), which is triggered by two pins on the flywheel.

Now i see two points that could maybe be done, without pulling the engine. First thing, would be to check if the valves close at propper timing. So open the valve cover, bring the engine to tdc and check that both valves are closed, then bring to bdc and check that exhaust valve opens, back to tdc and check that exhaust closes, intake open, back to bdc, exhaust closes. If this is way out of timing, pull the engine and check that the timing marks on the crankshaft and camshaft match. So that would be pretty easy to accomplish.

If that works out propper, it must be the timing of the ignition, since it should be timed by the two triggerpins, my first thought would be to take the flywheel nut off, then check if the flywheel key is sheared. If that is the case, pull the flywheel and replace the flywheel key. But if that isn't the case, where to look then further?

Try to adjust it, by adjusting the gap between the ssi and flywheel, since it can only be moved up an down, not left/right?

I got the Tecumseh technician manual for the cast iron engines, but interestingly it doesn't cover timing the ignition. What you think. Would be happy it it also would be able to test it, without opening the cylinder head, since a new head gasket is about 140$ to get here in Europe, and cutting one myself from aluminium or copper sheet isn't what I would like to do.
 
   / Tecumseh OH160/Case 1816 #2  
Is this problem something new or has the engine never run correctly?

is problem with engine at all temperatures?

Have you tried a different spark plug. Doubt problem but simple inexpensive thing to check

yes check valve clearance and operation

The only way that I know of to time that model of Tecumseh is the flywheel key.

going high RPM could be running lean from intake vacuum leak
 
   / Tecumseh OH160/Case 1816
  • Thread Starter
#3  
Propably been like that longer, but can’t say much, since i just got it a couple weeks ago.
Happens at all temperatures
 
   / Tecumseh OH160/Case 1816 #4  
You might try doing a search in the Sears garden tractor section. I know they used that engine in the ST16 model, as I had one. I read up on them and most common problem was the ss ignition module, which is now N/A. But, have read threads where guys have simply cleaned, and adjusted the pins/pickup, and they run fine. The modules that were not working, there is, or was an aftermarket one about a year ago I saw, for around $100-$125. There's even instructions/videos out there on how to make your own, using a Ford pick-up brake sensor.

At least yours is running, could just need cleaned, and air gap reset. The air gap for the long pin is 0.006" to 0.010", the short pin is the same.
 
   / Tecumseh OH160/Case 1816
  • Thread Starter
#5  
Can’t see the skid until weekend, so i will do the checks as stated before, the ssi is perfect, triggers right when the pins are under it, 400 ohms through it. Changing the ignition is not an option, either i get the engine back working propper, or i will exchange it. Not much sense in putting $ in a nearly 40 years old engine. But would be happy if the skid would run 1-2 years longer in that actual original setup. Once other components start to fail, i rather think about rebuilding it fully and exchange everything old.
 
   / Tecumseh OH160/Case 1816 #6  
Dad bought a used 1816 30 years ago, with no engine. He bought a new Tecumseh OH 160 through Padgett sales near Indianapolis. If I remember correctly, the standard crankshaft size is 1", but the 1816 OH160 engine crank was like 1-1/8" on the drive pulley end. They had a bushing that would size it up to 1-1/8". Just something to remember if you do decide to repower it.
 
   / Tecumseh OH160/Case 1816
  • Thread Starter
#7  
Yes, know about that, actually as far as i heard, they delivered it with 3 different crankshaft sizes, depending on the clutch type that was fitted (centrifugal, electric, manual) 1“, 1 1/8 „ and 1 7/16“. Got the electric clutch which should be 1 1/8“, but ofc if I repower it, then i will measure that. Biggest problem with the repower is that the components aren’t made up to go with the typical 25 hp+ engines, so you have to implement pressure relief too, or the pumps and hydraulic engines will fail way faster.
 
   / Tecumseh OH160/Case 1816
  • Thread Starter
#8  
Checked everything, inlet valve was at 0.2 set it to 0.05 and now it runs good again. But had to find that the cylinder head (exhaust port) is ****** up quite good. Had to seal using Al foil
 
   / Tecumseh OH160/Case 1816 #9  
If it is backfiring out the carb it is most likely carb related. Most backfires out the exhaust are ignition related. Try 1 oz. of Seafoam per gallon of gas in the tank. Let us know what the fix is...
 
   / Tecumseh OH160/Case 1816
  • Thread Starter
#10  
Adjusting the valve any ssi did the job
 
 
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