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Discussion Starter · #1 · (Edited)
I did manage to do a slight workover of the LI over Christmas break. This machine was coughing out a lot of smoke at startup and needed some work. The jug had a few shallow score marks and the piston had some definite blowby. It was bored .005 over at some point in its life.





Also discovered a burnt exhaust valve (always have side air deflectors on your working machines!) and two newer style lifter assemblies with the oil drainback groove.





I checked the taper of the cylinder using Gravely's ring gap method, and it was well within the limit. However, it does need to be bored .010 over because the ring gaps of the new and old rings were just slightly outside the limit. I cleaned things up, deglazed the cylinder, and put in my new set of .005 rings anyway just to try. The exhaust valve was also replaced and lapped in. Note how well the ".005" on the piston showed up in this photo.



I also had to repair or replace the fan shroud, fan, and gas tank so I purchased a parts '66 LI from a forum member. It turns out that my left bottom axle bolt has stripped out the threads in the transmission (sigh), so eventually I will swap out the transmissions.

Fan shroud before and after being welded by a friend with a Harbor Freight 90 amp flux core welder, and some grinding:





Interesting fan - I don't think it's original, but it seems to work well.



Few interesting bits on the parts tractor. I assume this was the last style of jug that Gravely used before the 7.6 style. I snapped off both exhaust manifold bolts but removed one with vise-grips. Actually, everything on this tractor was pretty easy to remove besides the manifold bolts and gas tank strap bolts.



Nice crack in the crankcase from some unknown cause, running up along the right rear corner and along the bottom. The piston, valves, and cylinder didn't look too bad.





Decent looking Hoof governor that I'll redo later on. Most of the linkage is gone but I won't need it for a while. This tractor had one grooved lifter channel and one non-grooved channel.



Anyway, back to the '63. I started taking apart the carburetor to rebuild it but ended up trashing the idle jet - someone before me had stripped out the screwdriver slot. So, I just yanked the carburetor off of my L8 and replaced the float (it needed to be done anyway). I've gotten used to Zenith carburetors, but that darn idle jet always gives me problems because invariably someone else has torn it up.

All back together with the saw. Parts came from GT Enterprises and Richard's. My only issue was with the top end gasket set from Richard's - it was missing both lower lifter gaskets, one manifold gasket, and one of the thin upper valve cover gaskets. I dug out some old gaskets and managed to make a complete set. The side air deflectors came from my L8.



I'd like to reverse the wheel that sticks out like a sore thumb, but it would hit the starter. I'll rotate the axle housings eventually.



An LI with GRWs means you have to constantly watch out for traffic... slow going. It's nice for driving through saplings though. In case anyone's wondering, I used the sulky to ride to the area that I cleared, and then removed it and walked while using the saw.



On the whole, the tractor is certainly better than it was. It does still burn a small amount of oil, but I figured it would since it really should have been bored out with a .010 piston. It runs really nicely until the plug fouls (20-30 minutes?), then it begins to "putt" now and then. I clean the plug before I use it next, and the process repeats. To be fair, I only ran the tractor for maybe 6 hours. The starter clutch really needs to be fixed and the seals need to be replaced on the 106 drive.

Also, when I attempt to perform the high speed mixture adjustment, the manual says the turn the main jet adjustment handle in until the engine begins to slow down. However, the engine never slows down and in fact speeds up slightly as I turn the needle in from the preliminary setting. Anybody know what's wrong? Something I messed up in the carb?

Thank you for your patience. This turned out to be a longer post than intended. Also, a big thanks to all the members that gave me advice when I was formulating a plan of attack for this tractor.

:thanku:
 

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There are a couple of things that will cause a plug to foul on a L.

1 - burning oil/low compression
2 - wrong plug
3 - too rich a mixture
4 - timing wrong

If I had to pick anything I would pick either timing or mixture.

There may be something wrong with the carb. Keep turning it in until it starts to falter. If you can turn it all the way in, then something is wrong. Maybe the idle mixture is way out.
 

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Discussion Starter · #3 ·
There are a couple of things that will cause a plug to foul on a L.

1 - burning oil/low compression
2 - wrong plug
3 - too rich a mixture
4 - timing wrong

If I had to pick anything I would pick either timing or mixture.

There may be something wrong with the carb. Keep turning it in until it starts to falter. If you can turn it all the way in, then something is wrong. Maybe the idle mixture is way out.
It sure feels like it has good compression, but it is burning a small amount of oil like I said. I tried both Autolite 3076 and Champion W-14 plugs, with neither making any difference. I did check the timing, and it's ever so slightly off. I'll fix that next time I'm home. Now, if I understand correctly, turning the idle adjusting needle in gives a richer mixture. I may have had it a dab too far out so I'll certainly double check that.
 

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It has been too many years since I messed with a L carb. I am pretty sure that the idle mix is leaner the more it is screwed in.
 

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Nice work! And thanks for the pix, I always like to see what other folks are working on.

Re the fan, I wonder if that was a gravely replacement part? My '43 has the exact same fan, and I also doubt it was original.

Re the carb, see http://oldgravelys.net/pdf/Zenith_61_161_Series_Op_Serv_19520700.pdf If I'm reading that right, the idle mix screw controls an air bleed, so turning it out makes it leaner.

I find I have to fiddle all over the place with mixture after doing a top end before it settles down. Sometimes the rebuilt engine will act like it wants an overly rich mixture for a couple hours, then wants to be leaned out or it will start to load up and foul. Doesn't make a lot of sense, but I've observed it on 3 different units now.

More pix please!
 

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You are right, the idle is reversed. It is the main that is normal.
 

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Discussion Starter · #7 ·
Nice work! And thanks for the pix, I always like to see what other folks are working on.

Re the fan, I wonder if that was a gravely replacement part? My '43 has the exact same fan, and I also doubt it was original.

Re the carb, see http://oldgravelys.net/pdf/Zenith_61_161_Series_Op_Serv_19520700.pdf If I'm reading that right, the idle mix screw controls an air bleed, so turning it out makes it leaner.

I find I have to fiddle all over the place with mixture after doing a top end before it settles down. Sometimes the rebuilt engine will act like it wants an overly rich mixture for a couple hours, then wants to be leaned out or it will start to load up and foul. Doesn't make a lot of sense, but I've observed it on 3 different units now.

More pix please!
That's good to know about top end jobs and carb settings. I always enjoy reading your threads and looking at your rebuild pictures! Hopefully another round of carb adjustment will get the settings where they need to be. The tractor does idle really nicely right now.

I don't think I have too many more pictures that aren't repeats, but here are a few:

Tag - LI M94565



Back view of the '63 LI and front view of the '63 L8 (M94897) - 332 numbers apart. I also picked up a newer style non-electric start hood to put on the L8 so that I could give the '52 L its hood back. I like the look of the newer style hoods better anyway.



Should also mention that the ES hood makes it hard to see the saw blade, so eventually I'll yank those parts from the tractor and put a Custom hood on it. A governor will also be nice. I think my L8 would be too fast for much saw work, although it should be easier to pivot into trees. The GRWs are a bear for swinging into larger saplings. In the meantime, this tractor is for my parents to use in the market garden (primarily rotary plowing and mowing) so I need to fix one of the starter clutches I have lying around.
 
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