Replaced sump gasket and crank seal, now it won't start.

[73datsun]

Picked up a JD LA165 that my local equipment rental place had taken on trade. I rented it to mow the lawn, ended up liking it, he sold it to me for $250. I was well aware that it was leaking (pouring) oil from the sump gasket. Tore it all down, put in the sump gasket and a crank seal.

I drained the oil prior to the surgery, but as it was sitting upside down, there must have been residual and it was leaking out of intake. When I flipped it over (after gasket install), I let it sit for 24hrs, sprayed some carb cleaner in the spark plug holes and spun the motor over to blow any excess out.

Put in spark plugs. Turn the key with butt in seat and brake engaged, engine just spins forever and never fires. Even tried starter fluid.

Motor: BS 24hp OHV 2cyl 44M777-0128-B1

Here's what I've checked:
Oil level - at spec
Spark plugs - new, not fouled - pulled them like 37 times to confirm, and they are getting spark
Fuel - working/pumping
Carb - taken apart and cleaned (but really it was spotless, not a hint of gunk)
Battery - new

It was a fairly simple procedure, and I don't think there was anything I really could have screwed up when taking the sump cover off. I'm at a loss, it's got fuel, air, and spark. Save me the embarrassment of having to lug this back to the shop I bought it from for service.

EDIT:
And now it gets more weird. I took the valve covers off, removed the plugs, hand spun the motor, I can feel the piston moving, but the valves are just sitting idle.

Video:

https://imgur.com/a/xEGau9n

Which leads me to believe I must have screwed something up in the sump gasket replacement process. But I don't know what, or how.

thanks

 

[Scrubcadet10]

Did you remove the camshaft or crank for any reason?
How did you verify spark was being produced?

 

[73datsun]

Did you remove the camshaft or crank for any reason?
How did you verify spark was being produced?

Nope, didn't mess with the crank or camshaft. Verified spark by pulling a plug, putting cap on, grounding it, bumping starter, and viewing spark.

 

[73datsun]

And now it gets more weird. I took the valve covers off, removed the plugs, hand spun the motor, I can feel the piston moving, but the valves are just sitting idle.

Video:

https://imgur.com/a/xEGau9n

Which leads me to believe I must have screwed something up in the sump gasket replacement process. But I don't know what, or how.

 

[tom3]

Check for valve action. Does the motor sound like there is compression when on the starter? There is usually a slide on gear that turns the cam and a key in a keyway for this. Don't know how it would get out but Murphy might have gotten in there?

$250 sounds like a good deal on that mower.

 

[tom3]

Oops, I was late to the party this time.

 

[tom3]

What kind of Datsun do you have?

 

[73datsun]

Check for valve action. Does the motor sound like there is compression when on the starter? There is usually a slide on gear that turns the cam and a key in a keyway for this. Don't know how it would get out but Murphy might have gotten in there?

$250 sounds like a good deal on that mower.

So basically, drain the oil (again), pull the motor, take everything off and see if I dinked something around in the process? Hard to tell what it would be just looking at parts diagrams.

Yeah, the equipment rental place is owned by a friend of the family. But he also sold it knowing it would need some bench time to get the gasket replaced. Regardless, a good deal once I'm able to sort my mess.

What kind of Datsun do you have?

Had. Dumbest thing I did was sell it when I bought my first house. It was a 1973 240Z, with the bottom end and flat top pistons from a 280z, which when mated with a 240z head, gave you higher compression. Then put on SU carbs, replaced the 4sp with a later model 5sp, etc. Project that I worked on throughout high school and college. Didn't grow up in a handy man style family, so it's a lot of taking crap apart, figuring out how it works, and then taking way too long putting it back together.

Like this dang mower.

 

[Mower King]

And now it gets more weird. I took the valve covers off, removed the plugs, hand spun the motor, I can feel the piston moving, but the valves are just sitting idle.

Video:

https://imgur.com/a/xEGau9n

Which leads me to believe I must have screwed something up in the sump gasket replacement process. But I don't know what, or how.

Make sure the push rods are on the lifters. Removing a sump pan without relieving valve spring pressure can move the cam and the push rods can fall off the lifters, rockers, among other things!

 

[73datsun]

here is usually a slide on gear that turns the cam and a key in a keyway for this. Don't know how it would get out but Murphy might have gotten in there?

Well you called it. Stripped it all down, and sure enough the Woodruff Key was sitting in the bottom of the pan. So the timing gear was just free wheeling and not actuating the valves. I'll read up on setting timing, etc and figuring out meshing these back together with key in. Still have no idea how it came out in the first place.

https://imgur.com/a/To3o8fs