First thought was to replace engine...but if you do that and then have transmission issues, etc, you are investing enough to have purchased a new one...I think I would go with a new one.

Update: Now he's quoting $540 replacement, 11 1/2 hp not including transport charge $35 and labor (with some alterations like the exhaust system). . . . 90 day warranty.

He's suggesting replace with new, rear engine Snapper.

Another thing to consider is my warranty. I'm probably only good here for another 5-8 years.

217907-3025-G5 is the current replacement engine # (OHV) BUT, says you have to change the crank shaft (715396)- so we hope whatever the dealer found is correct if you go that way. And it is more than you were quoted. Some online engine warehouses may have a compatible engine, though old flat heads are a tough find. If you can get by w/ a basic exhaust in your application- otherwise it gets expensive. His advise to replace the rider seems wise 2 me! Maybe you could source a good used unit. Or make sure he includes an extra tube of tire glue in the deal...

IMO engine replacement is only cost effective if you can do it yourself. Any time you have to go to dealer or repair man your going to pay retail prices on everything. I would just get new mower as suggested if I didn't have the ability to fit engine to the frame and get it hooked up. any engine will work if you have the same size shaft and the ability to adapt it to the mower. For some of us that's not even problem if we have spare parts to work with.

Thank you for the advices!

I don't have the know-how or tools to replace the engine with anything that doesn't exactly fit where the old one was. Repair guy would have to do the work. (At least I've found someone who seems to know what he's doing, unlike the people I used to go to attached to a JD dealership. The old engine had no oil dip stick and the former folks were extremely vague as to how much oil to use--hence the wrecking of the old engine. I, too late, now know I should have been been keeping it brim-full, something I've never done and something they didn't do either when they changed the oil once while attempting to repair other problems!)

I've located a reasonably priced and well-maintained replacement mower on Craig's list--should be delivered soon.

You might be able to pick it up cheaper and do it yourself.

Here is a link that might be useful: New replacement tractor engines

The PO of my '77 IH Cadet 80 re-engined with an 11 hoss B+S. Original was an 8 hoss. The engine is great , and I've been mowing my lawn with it for 10 yrs.

IMO--most folks with no working knowlege of gasoline or diesel engines in a lawn mower usage situation, should just bite the bullet and go buy a new machine from a dealer, and then paint the old one and set it out in the lawn, in a sort of shrine, testifying to its long and hard service to you! This will save a lot of cash, the grass will be cut as often as needed, the neighbors will think you are smarter than the average bear, and your wife, if you have one, will be glad you don't spend a lot of time out in the garage, trying to make a machine last another year or so. Why, you and she might get to know each other again, with your newly found spare time!