(noticed that my cut-and-paste editing of the message draft ended up skipping 'Q3' - sorry! - but never mind for now) -

He got the mower to start, although couldn't get carb off because of not knowing how to undo the linkages without breaking or bending something. The carb is held in position on two long bolts going into the head, and he didn't see a way to rotate the carb to slip them off, even with the fuel line unclipped/off. So he just blew carb cleaner through everything he could access and started it with some Seafoam to clean it out. But it doesn't want to hold the idle at low speed (wants to sputter and stall). Maybe a jet is clogged after all.

Of greater concern:
We could see where the oil leak was, seemingly from the gasket where the crankcase seats onto the flared section he said was the sump housing. We'd spotted some oil dribbling along the general area when the mower had been tilted onto its side, and he tightened the crankcase bolts found to be loose underneath (from the bottom side of the deck), hoping the gasket would seat better.
But it doesn't - the oil just poured out when he had it revved high, directly under where the cylinder head joins the crankcase.

He said when the mobile mower tech comes, to have the compression tested. If it's low, he didn't think it was worth the $$ to tear down the engine and start replacing parts.

I would be really grateful for anyone who's done work on Honda engines to say whether keeping this mower going is better than buying something new on the market. I like the way it mulches, the plastic deck is still in good shape, and if quality replacement parts could be gotten (Plano Power Equipment seems to be a good supplier), it might be a better mower with "refreshed" parts than what I could buy new today.

But what kind of labor am I looking at for engine work? Gasket replacement doesn't appear to be expensive parts-wise (for either the crankcase or head gaskets) but time spent to pull apart - ??? I have no idea how long it takes to take apart and re-assemble a lawn mower, by someone who knows what they're doing, of course.

how old is it? Is it worth all this trouble if its a 1990s mower...I mean if he can get it going great but...

Dumb question but I just did this on my in-laws Honda (I'm a toro guy)........is the fuel shut off...shut?

Thanks for replying.

To the best of what we could see, there wasn't an obvious fuel shutoff on this model, but if anyone can confirm that, it'd help.
The engine would run well enough if it was held at the choke or high-speed position, but not at the low-speed. It had to be "held open", is my best layman description. Dropping down the speed made it falter and want to conk out.

"how old is it? Is it worth all this trouble if its a 1990s mower"

I think it's either from '93 or '94 (my brother took our old Craftsman from us when we got the Honda, and his recollection was around '93, but maybe '94 since that's what the serial number suggests). It's been with me alone, since 2001 and used every season since. Can't speak to how it was maintained from '93-'00 (my late ex-husband would have done the servicing), but I had it serviced only a few times during '01-'12. :( Ignorance on my part on what to do, other than have blade sharpened. I'm sure it ran with dirty oil in it more often than not, although I did check the levels and it never seemed to burn any. Then after going to a shop for a tune-up and replacing the pull cord, it came back leaking oil substantially. Never knew if they did something or it was just the coincidental timing of the oil leaking after it was returned.

As to whether it's worth it to keep messing around with: I don't know. It's been a great mower and never let me down as far as starting after each winter. It mulches perfectly, so finely that it's hard to see the grass particles, if I mow at regular intervals and don't let the lawn get out of hand. The plastic deck isn't cracked and obviously won't rust.

The engine's oil leak is the big question now. I'd buy another Honda mower IF I knew that they would stand the test of time the same way this one did.

Carbs aren't that difficult to service on mowers (trimmers/2stroke stuff is a bit more challenging IME) and they aren't terribly easy to damage either. The most difficult thing when servicing a Honda mowers carb (as your bf alluded to) is taking it off the engine. I like to take pics of the linkages/springs prior to unhooking anything with my phone when dealing with an unfamiliar machine personally.

YouTube is your friend too, I've learned many, many, many procedures there.

Also, most carbs on Honda mowers can be purchased brand new for $25. Kinda makes cleaning one pointless to me!