Export thread

I finally got my lawn mower to start again and it seemed to work fine. I only ran it for maybe 5-10s, though. Then I replaced the blade because the old blade was completely rusted. After that I was ready to start mowing the lawn but about 3s after starting the engine there was this very loud metal-on-metal sound. I quickly turned off the engine. The sound seemed to come from the top of the lawn mower (the engine). I took the covers off again to check, didn't see anything suspicious and put it back together. I tried again but the same thing happened. What could cause this?

What kind of mower do you have? push or ride on?
does it have a plastic air shroud/ blower housing or metal?

It's a 1995 Briggs & Stratton push mower. Is the air shroud the fan on top of the motor that rotates? If so it is metal. The cover on top of that is metal and on top of that is a plastic piece. I was thinking maybe that fan was coming in contact with the metal cover but it doesn't seem so (though I can't be 100% sure). Actually, there is one additional change that just came to mind. Before when it didn't make that noise I didn't have the 'grass bag' attached. When I actually tried to mow the loan I attached the 'grass bag'. I wonder if that could create some different dynamics and pushes maybe the rod that connects the blade and the motor to the rod's wall. All of that stuff is pretty rusty but as I said, it worked before without that terrible noise.

In the dark have a good look over the mower using a flash light.
You are looking for something shinny where it has been hitting.
Reoil start bolts that are too long can foul on the fan, as previously mentioned the fan can foul on the housing

You replaced the blade. Is the new blade bolted in firmly? Is the new blade effectively longer because the old blade had ends rusted off? Are the mounting holes the same? Compare the 2.
There are sheet metal shrouds inside the deck that form a circle where the blade travels. Is a shroud loose and the blade nipping it?

Is it a loud squeal? Does your starter assembly have one of these?

Post all of your engine's model numbers.

Thanks for the replies. I used a flashlight to look for some bright/shiny areas. The only close to that I found is the metal piece attached to the fan (where the 'break' is). These two rings are suspicious but they don't look all that new.

There is a metal piece that goes over the fan. I inspected the inside of that metal piece but there were no signs of anything rubbing on it.

@dougand3 I also inspected the bottom where the blade rotates. No signs of anything rubbing the wall, either. In addition I put back the old blade just in case the new blade is the cause of the noise. However, that didn't make any change.

@Fish yes it has one of those. Not sure if it's removable. I would have to check again.

Also note that it actually take more in the range of 5s for the noise to start. The first 5s it runs as expected and then very consistently this really shrill noise starts at which point I immediately stop the mower.

When you pull the bail in does the brake cleat the flywheel.
The brake is the band that presses on the flywheel to stop the engine when you let go the bale to stop the mower.
It should have a brake pad type material on it but if that has worn through you could be getting metal on metal contact.

Take off the top again, and remove the 2-4 screws on the top of this "clutch", the screws also hold down the round screen on top of the flywheel. With a small screwdriver, pry up the "lid" and lift off the square thingee that rotates in the middle. You will see 6 ball bearings, take them out and clean them. Also. clean/buff the shaft that comes up through the center, and give it all a squirt of wd-40, but wipe up the excess. Re-assemble.

That should fix it. If it doesn't, don't run it this way, as it could destroy the starter innards when it totally seizes.

BTW, this was very common on the older Briggs engines.

Here,
I found this online..

https://www.youtube.com/watch?v=lmODx4b8WQ0

@Fish, you were right on!! I removed the grid on top of the fan. Then I could just pull out the crank shaft. There were 6 ball bearings inside. They didn't look that dirty but I went ahead and cleaned them. I also cleaned the inside with with some Acetone that I poured onto a towel. After that I added some WD40, removed the the excess and reassembled everything. I didn't think it would make a difference because it really wasn't that dirty but indeed the screeching went away, at least for the 20s or so I ran the engine. Thanks so much!!

It was a common thing on those older Briggs,
just says that I am old.......