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Short answer, yes, that sounds reasonable.

I've never set the timing on that engine, but overall it sounds right. You can eyeball check that you're at 19BTDC by looking at the piston position: it should be nearing TDC, maybe 1/4" below.

Not sure about 3/4 turn before the points close again. On a twin that seems a little long, as you're going to get another spark when you finish that turn. But really it's all about how they set up the ignition components: If the condensor has time to charge back up again, I don't see why you're not fine.

Actually, thinking a little more, all this stuff is automotive-derived. A V8 is sparking 4 times as frequently as our little twins at the same RPM. So I'm sure it's fine.

If one of the Onan experts sees this, I'm sure they can give a more definitive answer.
 

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Discussion Starter #322 (Edited)
I can pull the heads and verify the pistons are about 1/4” before full compression at 19 BTC, but they should be. When setting the tappets the piston is at full compression when the flywheel is at TC, so a quarter before when at 19 BTC sounds right.

I looked at the manual again and nothing other than the points breaking at 19 BTC is discussed. There is no mention about when the points should close. As long as the maximum point gap is correctly set at .020”, then I assume the points should be closing at the appropriate time. To be certain, I’ll recheck the gap again to make sure it’s not greater than .020” at any point.
 

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Discussion Starter #323
I've done that kind of thing on car and airplane engines. It often takes 30 seconds or more to prime the oil pump and then get oil pushed around to all the places it needs to go.
You weren’t kidding about it taking 30 seconds or more. I installed a mechanical oil pressure gauge on the dash and started to wonder if the gauge was broken, but then the gauge finally climbed to almost 30PSI.

Prior to turning the engine over and checking the oil pressure, I pulled the cylinder heads and checked the piston positions at 19 degrees before TC. Both sides were about 1/4” before full compression like you said.

Next is replacing the wiring to the coil, stator, and starter solenoid (sheathing is brittle and cracking), and then it will be time to fire it up.

Also, the wiring to the starter is direct from the battery. Seems like a fuse at the battery wouldn’t be a bad idea?
 

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You weren’t kidding about it taking 30 seconds or more. I installed a mechanical oil pressure gauge on the dash and started to wonder if the gauge was broken, but then the gauge finally climbed to almost 30PSI.
Yep. That sounds good. you got oil all through the system.

It's amazing how many people will just crank an engine over, and expect everything to be ok. Pre-oiling is easy to do, but often neglected. You should be in good shape for your first start.
Also, the wiring to the starter is direct from the battery. Seems like a fuse at the battery wouldn’t be a bad idea?
I'm not sure what the starting current is, but I wouldn't be surprised if it was 50A or more. You might find a fuse that beefy. Or not ....

It's actually pretty standard to wire the starter (only!) directly to hot. I wouldn't worry about it.
 

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50a fuses are easy to source in many styles, just replaced the one for the glow plugs in my Hilux.

But yeah I really don't think you need one.
 

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Discussion Starter #326
You all are probably right. Given the path of the starter wire, I imagine there is a very slim chance that it would ever get hung up on anything.

FYI - I just checked the Onan manual and the max current draw at NO LOAD is 60 amps.
 

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Discussion Starter #327 (Edited)
The starter wire attaches to two clamps attached to the cylinder head housing, correct?

So I started the engine today. It fired right up and ran smooth. However, I realized I have one more issue to deal with. I overlooked that my new tall points box gets in the way of the air filter. Any issue with putting an extension between the carb and air filter?
 

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Discussion Starter #328
Boomer, who I got the high profile box from, said he would swap a B series box for the high profile one. In the meantime I installed the original points box and took the tractor for a quick spin. I knew the front end was light, but without the mower deck or plow there’s almost no weight up there. In terms of adding weight, are there any pros/cons to adding weight to a front receiver vs wheel weights? Is one or the other better for the tractor?
 

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Discussion Starter #330
Ok. Thanks. I wasn’t sure if one or the other would cause unwanted stress on the tractor.
 

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Congratulations on your engine rebuild! It had to be great taking your tractor on it's first post rebuild ride. I know that there are differences of opinion regarding wheel vs. frame weights. Gravely made both. FWIW, my 44 inch blower weighs very close to 300 lbs. It's weight is supported by the frame every time I raise it, so I don't think I'd be overly concerned having a weight rack on the front receiver..

Our tractors do tend to have some "understeer" :) in certain situations, like trying to turn with the blower down as in the pic (wheels turned, tractor continuing straight) I bump the lift just enough so that enough blower weight is transferred to the front tires so that I can turn. Then I drop it again.




2485624
2485622
 

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Discussion Starter #332
Thanks, Tracktortag! It’s been fun, but more so has been a really good learning experience.

That’s some serious weight with the snow blower. I had no idea they weighed that much.

Great pics BTW. That’s some impressive snow you’re moving!
 

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Thanks! The "G" isn't mine, just a file pic I found so that you could see the factory front weight rack. The snow was from last week, about 8 inches. We would have had a higher amount but it turned to rain, then back to snow. The result was a heavy wet snow with about 3 inches of heavy slush on the bottom. Normally I would have plowed it at this amount, but it was so heavy, wet, and sloppy that I brought out the blower. I cleaned up with the plow.
2485735
 

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Discussion Starter #334
I’m impressed you can do that without tire chains.

The front weight rack is a neat addition. I’ve looked around online in the past and have never seen one for sale. I did find a 2” front receiver (GRAVELY FRONT HITCH RECEIVER 400/800/8000 UNIVERSAL | eBay) that I thought I’d use to attach a front guard with posts for weights. I figure that receiver may come in handy for others things as well.
 

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Well. there are a few things in play. Gravelys having a good part of their weight (including the engine/trans., and "the operator" at ~210-15 lbs. at last check, but that was pre Christmas :)) over the drive wheels, the Carlisle "All Trail" tires, which are great in snow, and a somewhat lesser known fact, a limited slip differential. I'm not sure about 812s, but 814s, and 816s built in 1972, and maybe a few early '73s came with LSD. It really works too. I can feel a slight "bump" through the seat when it engages. It doesn't happen often though. I could have plowed the driveway, but it would have taken longer than using the blower with this kind of snow. I positioned the 814 behind my wife's car in the garage before the storm and only plowed enough so the I could back her car out so that I could then get the 816 (blower) out. Then I used it to clean up after the blower.

Once in a while a Gravely weight rack will show up on ebay, but it's rare. They usually go for a good amount of money too since there aren't many around to begin with. Your receiver idea sounds like a good one. As you said, you can make up a weight rack (or have one made up) that will slide into the receiver, and still have the option to use it for other things.
 

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I’m impressed you can do that without tire chains.

The front weight rack is a neat addition. I’ve looked around online in the past and have never seen one for sale. I did find a 2” front receiver (GRAVELY FRONT HITCH RECEIVER 400/800/8000 UNIVERSAL | eBay) that I thought I’d use to attach a front guard with posts for weights. I figure that receiver may come in handy for others things as well.
Check this thread for building a front receiver for about $20 plus some Gravely scrap:


 
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Discussion Starter #337
Nice job on that front receiver! I already committed to buy one, but thanks for sharing.
 

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Discussion Starter #338 (Edited)
I noticed the gap between my starter sprocket teeth and flywheel ring gear is pretty big. Is this OK, or should I try to close the gap a little?
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Discussion Starter #339
I thought I’d share a pic of my oil pressure gauge. Unfortunately, the pilot on my hole saw came loose and the bit got away from me, so the surrounding area got chewed up a little.

Attached is also a pic of my 12v coil and fuel line for the pulse pump. Ignore the temporary copper wire holding the pulse pump in place. I’ll also make a bracket to attach the coil on the left side of the air cleaner. I was just using the parts I had on hand at the time.
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The starter/flywheel gap looks alright to me. I like your idea of installing an oil pressure gauge. It's nice to be able to see how much pressure you have.
 
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