Most of those mowers have bolts and nuts that hold the engine casting to the housing. Those tend to back out over time, whenever i run into those problems i use the locknuts with the nylon insert and those never back out. Even if your model has self taping screws into the casting you should be able to use longer bolts and install nuts. The only real problem you may have is if the sheet metal housing around the bolt should break off due to rust or vibration. In that case be creative with fender washers or depend on the remaining holes to hold the engine to the deck.

Ok, the nuts and bolts seem to make sense. It seemed that the bolts were loose in the holes, making me worried that they were stripped. It seems that the plate between the engine and deck is cast aluminum. Is there a gasket or something that goes on there to seal the exhaust port? I guess I'll have to tear into it to see just what I have. I have never worked on a lawn boy before, so I have no clue what I'm getting into. It also seems that the lower crank seal is shot. It is oiling the deck and the belt. The belt is worn out and oil soaked. I had it running, but it seems to be running lean and surging with the choke fully off. I'm guessing due to the bad seal. Where is a good cheap place to get the belt and seal? How hard is it to change the seal?

Also, the model and serial numbers are: M# 680541 S# L009B0209

On the engine it has the number L21ZSM 4HP.

According to lawnboy.com, this model/serial number doesn't go together. Also, it says this model is a 5HP 5 speed mower. But, it clearly has no ground speed control, and the engine says 4 hp. Can anyone tell me what this thing is?

Just looked at the Toro Master Parts Viewer. The drawings they have look like the mower, but I don't understand the 5-speed part.

It looks like it takes a 611396 seal, and 613884 belt. I also see that there is a toro dealer close by. I guess they may have or can get the parts?

there are 5 ground speed settings possiable with this model. you remove the drive pully and add or subtract washers to gain or loose ground speed.

Hmm.... Like a variable pulley and the washers shim the two halves together or apart. I guess I'll see how that works when I tear into it.

Just took a few new pictures and I have a couple of new questions. First the pics.

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This is the blade. It doesn't look like a mulching blade to me, but it came with the mulching cover. Also, what is this mulching fan people are talking about? I guess I don't have that. Do I need one? Also you can see that there is still green paint under the deck.

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This is where the bolts are loose. Is there a gasket that goes on the exhaust port? Also, it looks like the bolts are threaded into the casting. I don't see any way to use nuts on these bolts. If they are stripped, can I heli-coil them? Any suggestions?

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Here is a picture of it after I hosed it off. Looks like it has been stored inside. Should be a great mower if I can get it going.

yes there is a gasket that goes between the engine and mount plate. you might just get lucky and only have to tighten up the bolts . you wont know till you get it apart. search for threads here that deal with removing the blade adaptor . this can be a tough job on lawnboys

Yeah, I know about the blade adapter. I tried to hit it with a hammer, but it wouldn't budge. So I heated it carefully with a torch and then it popped right off. Due to being anxious about getting it going, I did not wait for advice. I found the bolts adjacent to the exhaust port completely loose and sitting inside the muffler. The other two bolts were about half out. I went out and matched the belt, or what remained of it, to a 3L330 belt. I put on the new belt and remounted the motor, but did not use a gasket. There was not one. I guess it fell out when the bolts got loose. Am I going to have to take it apart again and use a gasket?

Anyway, It seems to run great. There was no carbon inside the muffler or exhaust ports, and the piston looked good. No scuffs. It runs a little lean until it warms up a minute or two. I don't know if this is normal or not, but it smooths out after a little warm up. That blade is not a mulching blade. It leaves long clippings, but it didn't do too bad. Where do I get a gator blade?

That 5-speed setup is weird to me. I set it to go top speed, but I could not figure how to get five speeds, only four, with three washers on the pulley. Also, I could not tell how the clutch system on the gearbox works. Seems the input shaft spins all the time, and the cable moves a lever on the gearbox to engage the drive.

I can't see the advantage of the staggered wheel deck. Seems on rough ground the right front of the deck digs in without a wheel up there. Could someone enlighten me?

All in all, this is a great mower. I can't wait to get it on a steep slope I have been mowing with my steel snapper. That thing weighs a ton. Also, that hill killed my last engine, so this 2-stroke will be lots better suited there. It mows good, drives good (a little slow though), and is smooth as glass. I can see why you guys are addicted to these green machines!

Hey there fix it, great little mower you have there. I love those "F" series engines. If I were you I'd get a gasket for the exhaust. They run a dollar or so. Be sure to get GENUINE lawnboy parts from the Toro dealer nearest you. The material that Toro uses is a metallic material not really sure what it is but it is way better than the cheap aftermarket paper gasket material.
You can still use the machine but it will be a little louder and have some carbon blow-by on the deck area around the mating surface but you just as well do it right. Sounds to me like you have done real good so far.
I suppose you could use some high temp gasket material from a auto supply store and cut to fit. Its a rectangle so it should be easy but if you have a dealer nearby they should have some in stock.

Good luck and thanks for the pics.
Neal

I'll check on getting that gasket. I still need to find a gator blade for it. I noticed that it has a grease fitting on each of the rear wheels, and on each end of the axle. That's for total. How much grease do these take?

So far all I have in this thing is $3.00 for the belt. I'm pretty sure that it isn't exactly the right one, but it fits and works just fine. I think a 3V330 or 3VX330 would be closer. But it's better than having to order a $20 belt from Toro. The mower was free. It looks like it has been stored inside. It's 15 years old and other than being dirty, it looks like new.

You can get a gator type blade from Oregon aftermarket supply.
They make a good blade, I have them on my 10515's and they perform well. As for the Gator brand I'm not sure where to tell you to go. My Toro/lawnboy dealer also caries gator type blades in stock, they run around eighteen bucks I think.

Twenty dollars for a belt! Man thats robbery! I pay between five and eight dollars for the ones I buy from Toro.

As for the grease zerks you can just add grease till you see it coming out the seal, or around the shaft whichever comes first, not sure on that model though.

Does it have a metal carburator? If so you have a keeper.
Have fun, Neal

www.landscaperpro.com or www.j-thomas.com for a lawnboy gator.

A new exhaust gasket and a drop of blue loctite on the cleaned bolts and bolt holes will keep it together longer and help with the oil mess. Good luck and enjoy a fine piece of lawn mowing craftsmanship!

Yes it has the metal Walbro carb. I took it out and mowed a lawn with a steep hill today. I have been mowing it with my snapper. This thing worked great. Much easier to handle that the snapper, due to the light weight. Also, where the snapper will spin one wheel and stop, the Lawnboy will drive with whichever wheel has traction. No more getting stuck. I do miss the variable speed though. Speed it up for flat ground or slow it down for the hills.

I can't decide if the exhaust gasket or the lower crank seal is oiling the deck, but it is one or the other. How hard is it to change the seal. I can pull the blade, muffler, and mounting plate off. Then I guess I'll have to pull the pulley. After that I don't have a clue. Any tips for that?

Where on the deck is it getting oily? If the seal is going it will oil the crank shaft. If its around the exhaust area I'll bet its the exhaust. Just replace the gasket and go from there.

BTW, The pully should have a set screw for removal. I get mine every time with a propane torch and the screw always backs out. You have to be careful of the seal down there though when heating I put a wet rag around the seal area to keep the temp down.
Neal

It seems to be spraying an oil mist on the mulcher plate and surrounding area. It also looks like the crank has oil on it right above the pulley. It looks like there is a rubber piece around the crank but it is hanging down almost touching the pulley. I don't know what a good seal looks like, so I can't say if this is good or not.

your lower seal has fallen out. mine did the same thing. i just pushed it back in place and its held for about a year. i am shure i will have to take it apart and replace it sometime.

Oh my, You're seals toast if its touching the pully. I'm suprized the machine runs as good as you say. Just imagine how it will run when you get a seal back in there.
You really need to consider replacing the seal. Its really not that hard of a job, but can be time consuming.
You need to remove the blade, driver, muffler, pulley, cables and remove engine from the deck but it can be done still attached, but I do for convenience. Pry the old seal out with screwdriver and put new seal back in with a piece of pvc pipe or equivelent that will slide over the crank shaft and tap the new seal in place till it seats.

Study these repair manuals for the "F" series engine before you do it.
Neal

Here is a link that might be useful: repair manuals

you can indeed use a peice of pcv pipe but you have to custom girnd down the lip to get it to fit.

Thanks for the advice on the seal. It does run great. Seems a little lean when you first start it, but after a minute or two it runs fine.

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This is a view of the seal. I tried to push it back with a screwdriver, but it wouldn't stay. Also, the spring is loose on the crank. I guess I'll have to change it. Doesn't look too hard. I can't imagine that it is too expensive either. I also find it amazing that it runs like it does without a lower seal. That would explain the oil soaked drive belt and the matted oily grass under the drive cover.

Does the belt look like it is sitting in the pulley properly? As I have never worked on one of these, I have no idea what type of belt it is supposed to have. It seems to fit OK to me, but there are a couple different shape belts and obviously some will fit better than others.

You can also see the metal carb on the right. I assume this is a benefit of the commercial engine. What is wrong with the plastic ones? Do they warp?

Seems I'm learnig a lot about the Lawn-Boy thing.

I too has also found my seal lowered on my commercial self drive lawnboy.It was spraying a fair bit on the deck and belts.