My mower :frown:

[Highpockets]

Howdy everyone. I've got a '92 model 680544 2 stroke... in pieces. I bought a short block back when they could still be had. I had thought about just selling it off for parts, but I'm having second thoughts. After reading about how much you guys love these old mowers, I just might have to see if I can put the old girl back together again. I read on one of the posts that the later model mowers were "throttled back" to meet the EPA requirements which also made them a little more anemic in heavy grass. Does that apply to my year model and is there a fix for that? If I tackle this project, I'm SURE I'll be looking for some help at some point.

I'll post some pictures when I can get them from my phone to the computer. (My company doesn't allow!)
Highpockets (should be EMPTYpockets!)

 

[Rivets]

To my understanding the two cycle engines were never "throttled back". I would put it back together, seeing that you have the short block already. This website will probably help, even though it does not cover your year.

https://lookup3.toro.com/ttcGateway/acrobat/manuals/lball.html

 

[Two-Stroke]

That's an F-series engine. The comments about "throttling back" were about the Dura-force engine, so you don't have to worry about that.

Good luck and please let us know how you're getting along with it.

 

[turfboy1997]

Its not a matter of them being throttled back. its a matter that they have no air adjustment to set the mixture right causing them to run lean. This makes less smoke but makes the engine run hot and in my opinion less power. i have mowed with both engine types and the F is quieter and smoother than the duraforce. When i get another duraforce it will be re jetted to stop the surging and make it run cooler with the full 6.5 hp. Your model is an F series and i would get that thing back together asap and use it. they are amazing! i have one that is one year newer than yours that i am mowing leaves with and i have been mowing piles of leaves with zero bogging and have not killed it yet. When you get it back together take the air adjustment screw facing the front of the motor on the carburetor and screw it to the right until seated. Turn the screw to the left 1.5 turns. Warm it up for about 3 min full throttle. leave it running and adjust the screw to the right slowly until the mower smooths up or you can leave it at 1.5 turns and it will be slightly rich. I have done this to every lawn boy pre duraforce and works like a champ!

 

[robinb66]

The 2 best lawnboy production motors ever made were the d400 series, and the f series. Cant go wrong with either one!!!!

 

[jameshobbs]

When I was in high school I worked for the state of Tn top selling / servicing Lawn Boy dealer. I was the only service guy. I was factory trained & certified. Lawn Boy The corporate parant was ( Outboard Marine Corporation) backed there product & dealers up to the max !
It was a sad..sad day when Toro bought them in 1989 ! They sucked all the technology out of the company and then slapped a B & S on the Lawn boy frame and started selling them at big box stores. They did not care about service or the small guys that had sold and serviced Lawn Boys for years
We had a customer that had a 1957 or 1958 QUIETFLITE ( it had points & cond. ) 2-cycle Lawn Boy he would bring it in every 2 or 3 years for a tune-up, it always started on the 1st or 2nd pull !
The "D" engine was / still is a work horse ! It was one of the first if not the first small engines with CD ignition system ( no points & cond. )
The "F" engine was refined and had a better governing system to plow thru high grass with no problem after you re-jetted them.
The EPA was coming down hard on 2-cycles engines for exhaust gasses so Lawn Boy leaned the crap out of them to comply with the EPA rules of the time. So they were running hotter because they were running way too lean. They were not only was running hotter because of the lean jetting they were losing low end torque because they could not rev fast enough and high enough to pull the load under wide-open loads. 2-cycles engines run at wide open load 85 -95 % of the time compared to a car that is under wide open load 5 -15 % of the time.
I would put a Lawn Boy "D" or "F" engine up against any small engine ( bar none ) for power & performance but most of all durability. The thing is bullet proof !