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Discussion Starter · #1 ·
So I have a successfully scored on my first deere hunt. 1967 112, it has a rebuilt HH100 that has never been started after the rebuild, 4-5yrs ago and a nice 39 deck. We put an oil plug in the bottom(!), added oil, checked the points, threw the engine in the frame,and gave it a shot at running.
Big surprise, gas tank had 3 inches of sludge in it, ignition switch was bad, starter solenoid was bad.
Replaced the gas tank, jumpered around the switch, replaced the solenoid with a ford one temporarily and then the carb was giving us attitude. Tore it apart and its a mess. Anybody got any ideas where to get parts? Are the kits on Ebay worth the money? It was rebuilt with the engine, but it needed help. The float has been massaged with a big screwdriver! Ugh.

As we brought it home:


Engine installed:


Engine tag... can I get a little help decoding this?


Serial number, its already in the DB by the previous owner. How do I get that changed?
 

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Discussion Starter · #3 ·
Another question regarding the engine output shaft sheave pulley. The PO's son "removed" it and busted a chunk out of the lip of the inside pulley grove. I didn't get the piece. I am assuming this is a hard to get pulley haven't seen any on Ebay. Will any pulley off of a 1966-67 112 work? Will one from a 110 work? It has four equal size pulley groves.
 

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Scott the engine sheaves are specific for the 66' and 67' 112 as you suspect....since it was designed for the 47 deck. There are two groves for the pulleys on the "outside" of the sheave. A sheave for a 110 should fit but then the PTO mechanism (if included) will need to be swapped out. If not your belt will not line up properly with the mule drive to power the deck.

I know of a couple folks that have repaired their sheave doing what k b described. That might be the faster route.

Good Luck!
 

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Discussion Starter · #8 ·
OK, back to this tractor....and the problems I have been handed.

Started with a carburetor rebuild. Couldn't adjust the float and eventually found the viton seal was missing from the last "rebuild." Ordered a kit, new float, rebuilt, (yes, Roger I had to buy a replacement main nozzle because it had been previously removed!) and then the engine had gas and spark...but did not ever fire more than once or twice over a 30 minute period of trying, checking, trying.

Eventually did a compression test (note the engine had been rebuilt but never started), got 20 lbs. NOT GOOD. So we tore it down a little further, pulled the head, checked the valves. Exhaust valve had 0.010" clearance and intake had about 0.005". Piston was standard and the bore was 3.312" according to my handy dial ind.

Now this is where I needed a little expertise from you guys, I watched the valves and what seemed very odd to me was this: during the compression stroke (both valves should be closed) I noticed the exhaust valve would open ever so slightly, then close again as the piston reached the top of the cylinder. The rest of the timing looked correct for the intake and exhaust strokes. Is that supposed to happen on these HH100s? I am new to the RF world so any advice is good advice.
 

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I have never taken a Tecumseh apart. By looking at JD parts.com, Tecumseh engines have a simular ACR, automatic compression release, as the single cylinder Kohler engines. This device is mounted on the cam gear and has a tab to hold the exhaust valve open when the engine is being started.
 

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Just to be clear, what Edward described is what causes that momentary open of the exhaust valve. I can't explain the 20 PSI, but did you check to make sure the points are opening and closing? I know people say that you cannot get a good compression test on the K181 and HH100 because of the ACR, but as a reference, I checked one of my HH100 the other day that is running quite good and it was at 90.
 

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Just as with a Kohler, it's not possible to get an accurate compression reading with a working ACR the conventional way. I do not have a dimension for the actual lift of the exhaust valve during ACR but it will vary with actual valve clearance and wear on the ACR lobe.
The valve clearances are - intake 0.010&#3#34;, exhaust 0.020" cold. The HH100 is more like a K181 Kohler in valve setting as there is no adjustable tappet. The valve stem must be shortened to gain clearance and the valve seat/valve face must be ground to decrease clearance.

Wonder what was actually rebuilt?

Here's a fuzzy photo showing part of the ACR mechanism.



tommyhawk
 

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I can't believe this is the case, but since someone did take this engine apart I will share what I just fond on a HH110 that I had to take apart because the PO had left it out in the weather with no spark plug so stuck valve etc. When I opened it up I took a close look at the timing mark on the cam to the special slanted tooth on the crank. Mine was off by 1 tooth. I thought I was not seeing it correctly so I turned it several revolutions, but it is in fact off by 1 tooth. I wonder if the person that rebuilt yours knew what they were doing. You can't be sure what yours is like. From your measurements of the valve gap it seems they did not do that correctly. What else?
 

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Discussion Starter · #13 ·
Well thanks for the ACR explanation makes more sense. Now that you all have explained it, I did find it in the SM2059 manual as well. Although. I do tend to agree with Bill, I am not taking anything for granted, I will probably pull the side cover to see if its a tooth off.

Tom,
You state "The valve clearances are - intake 0.010", exhaust 0.020" cold" But my manual for the tecumseh says 0.010" for intake and exhaust. Where did you get your numbers? I want to make sure we are shortening the valve stems to the correct gap.

We (my dad and I) will probably Dyechem the valves and make sure they are seating as well. If I have to re-cut the seats, then I would have to go back and shorten the valve stem again.
 

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Scott, those numbers are from JD service manual (SM-2088 Nov.69) for early square fender tractors. I just double checked to be sure but that's what this one listed. I would not expect the earlier models to be different, but good for you for noticing a difference in another book. I don't have a Tecumseh manual for the older ones.
What book are you using?

tommyhawk
 

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I got out the JD manual (SM-2059 NOV 68) for the RFs, and it shows the same as yours- 0.010 both cold. You should stick with that.

I wonder if the Tecumseh Engine Manual has a serial number break for that. Maybe Tecumseh switched to the hardened seat and Stellite valve while they were building the engine for the '68 model tractor. The different material could "grow" more when heated, thus requiring more initial clearance.

I can't read the foil sticker on your flywheel shroud. Does it say anything about the valves? Does your manual say much about the exhaust valve material?

tommyhawk
 

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Took a look at HAPCO's decals. The '66-67 appears to be the same as the '68 with stellite exhaust valve shown.
Another question. How flat is the head and what condition was the gasket? Leakage there may have kept it from starting more so than the out of spec. valve lash.

tommyhawk
 

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Discussion Starter · #18 ·
A little update here:
We lapped the valves this weekend, I believe the PO bought new valves, put them in and didn't check the pattern. Then filed the intake stem until we had 0.010" clearance. Reassembled, and after a few times cranking it over, we got fire!!! The engine ran for about 2-3 minutes on its own. We did have to feather the choke and throttle to keep it going. I think I am now down to or back to carb issues.

When we shut it off, the carburetor started puking gas. So either the float is too high or the needle is not seating good enough on the viton seal. Do you have to "break in" the viton seal if its new?
 

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No break in that I'm aware of.
The last time I did mine, it did that also, but not for a few weeks. Could not find anything wrong with the new parts either. After ruining a new air filter I re-installed the old needle and seat. No more leaks after 11 years. It does just sit covered most of the year but comes out running for the local show every year.
Hope you find the problem.

tommyhawk
 
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