I saw this in one yard last week. Are you positive it's not a swirl mark from spinning too quickly?

I am sure it is from the engine blowing air over the exhaust and not a swirl from driving or the blades. I parked the mower, stopped the blades, marked the wheel location, let it set for a couple minutes running, then drove away. All under a controlled situation and yes it left a brown burnt spot the next day. It appears to be cooking the grass. There has never been a leak of any kind on the garage floor.

Sounds like you have identified the problem then.

A few years ago, some people were reporting "angel" or "butterly" shapes scorched into the grass. It would happen because they'd park a running tractor and the cooling air came down across the engine and down onto the mowing deck and then out across the grass.

The solution was to not park a machine with a running engine on the grass.

The catalytic converter on your car will do the same thing and/or light the grass on fire if it's dry enough.

That should have been "butterfly", not "butterly".

There were some guys on the Cub Cadet board on another forum saying their new Cubs were doing the same thing.

Not parking or stopping in the grass may be the ultimate way to stop the problem but not a very practical or real world solution. What a pain stopping the engine every time I need to pick up a stick in the yard, not to mention extra wear on the starter. Any idea if the Cub guys found a fix for the problem? I am waiting for the TORO district service rep to research but do not hold much hope for a real answer or solution.

Yes, its inconvenient. Its an artifact of our desires for our tractors to have massive engines so we can do wheelies. Its an artifact of legislation for mufflers (and catalytic converters?) on our tractors to clean up the exhaust and kill the noise. Its an artifact of market research that says every lawn tractor needs cup holders, 4 way adjustable padded seats with armrests, headlights, power steering, 4 wheel drive, etc. All of these things are nice. But they mean we need to watch out we don't burn the grass when we stop by killing the engine, or we need to park it off the grass when we get off.

John

A short term solution to the "stopping to pick up sticks or other" aspect of the situation might be to purchase one of those "reach extender" devices (has gripper jaws operated by a large trigger shaped lever you hold in your hand). This would allow you to pick up the "stick or other" without stopping long enough to burn the grass. Whether you "rig" a catch bin on your tractor to hold the objects or just toss them onto the part of lawn already mowed to be collected later would be up to you. I have three of these reachers around for when I drop something and it runs up under a shelf or table to hide. One of them actually folds in the middle so you can even stow it on a tool belt if needed (I'm not suggesting a tool belt to go with your mowing attire, but if it fits in a loop on a tool belt, you could stow it almost anywhere). That one has rubber cups for grippers and can pick up coins from a hardwood floor and is strong enough to retrieve cans of food from a pantry shelf.

My Snapper ZTR does the same thing. I e-mailed Snapper about it but never heard anything back. I carry one of those extended reach grippers with me now. I am still thinking about fabricating some sort of heat shield under the muffler.

I have a Question!Does the Z5000 or other ztr types have a safty switch on the seat that prevents you from getting off while its running like other tractors do.If not!!just curious why it isnt needed.From what ive been reading here it seems you can get off without the engine shutting down which is a no no for lawn tractors.

"I have a Question!Does the Z5000 or other ztr types have a safty switch on the seat that prevents you from getting off while its running like other tractors do.If not!!just curious why it isnt needed.From what ive been reading here it seems you can get off without the engine shutting down which is a no no for lawn tractors."

Oh, that safety law doesn't apply to the ZRT mower elites. When you have to pay above $4K for a mower, they figure you should be cut some slack. This ruling was recently upheld in the courts after vigorous protesting by the ZRT Lobby.

(just kidding! Wish I had one;o)

The other option is to walk around and pickup sticks before you start mowing.

I have 2 dogs, so walking the lawn to pickup "things" is a mandatory job or I end up with a big mess.

I have a lawn tractor that will not shut off when you leave the seat, but the blades must not be engaged when doing this or it will be shut off. Must have parking brake on and pto disengaged when getting off tractor. It is a 2007 Husqvarna YTH20K46. There may be some other models that do this also.

Talked to my Toro dealer today. Like the thread starter I was told the district rep would be notified of the issue. While I was there I got to looking around at other residential ZTR's and noticed that all of them have a heat shield in addition to the muffler outflow redirect cap. Looking under the Toro exhaust I can see screw holes that seem to be there for a heat shield. This shield I think would solve the problem and IMO is an oversight by Toro.

I am guessing that a heat shield is the answer. Maybe by the end of the mowing season TORO will correct the issue. The Z5000 does allow you to get off the seat while running as long as the mowers are stopped. I think you also have to have the handles in the park position, this is actually required so the mower doesn't slowly move on its own.

Well wadda you know . . . My Toro dealer just called and told me they have a prototype heat shield for me for the Z5000. I'll pick it up tomorrow and let you know if it solves the problem. Who says service is dead.

Seems like you found a good solution.

I was going to suggest using an exhaust wrap. I wouldn't think you'd need more than 15 feet of it (a small roll, comes in 1 or 2" widths too). Its made of fiberglass and will withstand continuous temps up to 2000 F.

Used a lot on motorcycles to prevent burning your legs on the pipes.

Picked up the prototype shield yesterday. From looking at it even though it's designed to fit around the muffler, it looks like it's meant to deflect the heat coming off the ENGINE rather than the muffler. It's in 2 pieces that fit around the muffler blocking off most of the open space between the frame and muffler. Apparently the air from the fan and flywheel is pushing the superheated air straight down. While this may fix the burn spot issue I wonder if it will cause the engine to run hotter.

My Toro LX460 burns a 2 foot patch every time I cut. All it takes is 30 seconds off the mower picking up sticks or chatting with the neighbors. I thought I had bugs for the first year I owned this mower. It leaves a patch similar to a chinch bug, but figured out it was the heat from the engine or exhaust. I hope they have a fix for this.

I recently purchased a Toro 42" timecutter and everytime I cut I am getting round burn marks. I am not getting any help from Toro at as to why this occurs. They seem to be unaware of this problem with their mowers.

Can you please give me some advise on how to fix this issue?

Thank you.

I had a timecutter that would burn the grass. My wife could not control it so we went back to a tractor. You are gonna have to redirect the outlet pipe. A muffler shop could help.

I bought a Toro TimeCutter MX4200 about 6 months ago and notice dead grass spots after each mowing. My dead spots are circular and about 10" in diameter. They start showing up 1-2 days after mowing. BUT they clearly look like fuel was spilled because the grass turns very light yellow, dries out, and completely dies in about 3-4 days. The spot is in a different location each time.

I haven't done focused testing to narrow the problem, but based on the locations it's happening where the mower is changing states: either throttling up/down and/or engaging/disengaging the blades. I don't know which of these is the cause. I don't seem to have the burned grass in locations where the mower travels without such a state change (ie. riding it with or without the blades spinning). My driveway & walking paths split up my front lawn in about 11 "sections" separated by raised belgium blocks, so each time I move between sections I disengage the blades, raise the deck to max height, and sometimes throttle down, and then do the same in reverse in the next section.

My blind guess right now is that when one of these state changes occurs some fuel leaks or gets expelled.

Unfortunately I forgot about the problem while using the bagger to pickup the leaves across my lawn the past few days, and had a ton of these state changes all across the lawn as I emptied the bags. Now I'm starting to see dead spots everywhere. Ugh!!!

Following up on this, I spent some time scrutinizing my mower for a fuel/oil leak and the most I found was some grass/dust residue stuck to the oil dipstick pipe. Nothing close to a leak or enough to explain the regular dead grass spots.

Couple observations lead me to believe this is not a fuel/oil leak:

1. The burn spots grow back in 1-2 weeks which means it's very unlikely a fuel/oil leak since grass will completely die and not grow in soil contaminated with petroleum.

2. The burn spots are about 1 ft in diameter which would need a "spray" of fuel rather than a drip.

So unless fuel is spraying in a fine & light mist that only touches the grass leaves and doesn't get into the ground, I'm starting to 2nd guess the cause of my dead grass spots and maybe I'm suffering from the same exhaust heat problem. Placing my hand under the exhaust while the ZTR is running even at idle it's quite warm at the grass level. I can only imagine the temperature at full throttle.

Unfortunately I still haven't found the definitive cause. I'm considering video recording the full mowing using something like a GoPro so I can then look at the footage to find what was going on near the burn spots to give me some lead(s).

I mentioned this problem to the retailer & service center where I purchased the mower and it seemed new to them. They sell other pro- and commercial brands like Skag and have been around for decades, so it might be just that they don't have enough residential homeowners with Toro ZTRs to get a lot of reports.

I also use one of those "gripper" tools to pickup sticks but usually I'm only stopped for couple seconds using it.

I'm going to look into options for a heat shield.

A diffuser shield would reduce the amount of direct or concentrated hot air that is being blown onto the grass . A perforated piece of thin body metal would be effective in this redirecting of the air flow .

I have the same problem but my burned spots are usually rectangular and about the same size as the muffler on my Toro Timecutter MX4200.

I have the same issue with my 42in Toro, just got it two week ago

Two weeks old , get back to the Dealer for their inspection onsite , either they fix it or refund your money !

I have had a Z4200 for 3 years. It came with a heat shield but if I shut it off on the grass while I do something else it leaves a burn spot about 12" in diameter. My solution is "do not park it on the grass after or during mowing".

After 2 years with toro75755 this issue is still there with no fix from toro. Toro advised to not park on the grass while at idle. While this has been inconvenient the mower does do an amazing job otherwise.

I've seen it as well! I don't know if it's necessarily that you have to come to a complete stop but any slight pause. I think it may be an issue with smaller Zero Turns the John Deere that I had prior to my Toro did the same thing.