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Lawnmower is making loud metal on metal sound when started

Posted by wackylawnmowerman (My Page) on
Sat, Mar 14, 09 at 16:41

I was cutting the grass last summer and out of the blue the engine starting making this awful metal on metal sound. It gets louder when I apply more gas. I checked the blade housing and it's okay but the sound is coming from within the engine itself. Any ideas on what this may be? Thanks guys


Follow-Up Postings:

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RE: Lawnmower is making loud metal on metal sound when started

You could be describing lots of things. Scraping noise could be an issue with something scraping against the flywheel such as the coil or brake. It may be helpful to tell us what equipment and engine this is and define the noise a bit better if you can.


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RE: Lawnmower is making loud metal on metal sound when started

What kind of metal to metal sound, scraping or knocking?

IF knocking, check the motor mount bolts.

Walt Conner


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RE: Lawnmower is making loud metal on metal sound when started

It's possible the blade is loose or bent, as well as loose motor mounts as Walt said. Worst case, it's getting ready to throw a rod. Have you checked the oil?


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RE: Lawnmower is making loud metal on metal sound when started

"I was cutting the grass last summer and out of the blue the engine starting making this awful metal on metal sound. It gets louder when I apply more gas."

It might be helpful if you posted the make, model and type numbers of the engine. For example, the counter weights of some B&S engines on rare occasion, come apart making noise like this and evenually, a hole in the engine.

Walt Conner


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RE: Lawnmower is making loud metal on metal sound when started

Let's eliminate the most likely candidate first. The blade.

1. Inspect the blade for obvious bends and breaks.
2. Using a wrench check that the blade is tight.
3. While the mower is on it's side rotate the blade by hand to see thatthat it rotates in a flat plane.
4. Carefully check inide the cutting housing for any signes of contact with the blade. Be sure to check around the grass chute as some parts will be fairly close to the blade.

I'm sure you know this, but before attempting any inspection be sure to remove the sparkplug wire from the plug.


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RE: Lawnmower is making loud metal on metal sound when started

It's an old craftsman mower, 10 hp / 5 speed riding mower.

It runs fine. I mean I get the same sound regardless if the blade is engaged or not. I've already checked the entire blade housing and the sound is coming from within the engine itself....could it be a thrown rod?

When I say the engine runs fine I just mean that it starts and runs around but is so loud that the neighbors come out asking if I'm alright because the noise is so loud.

I found a picture of the lawn mower on line. Sorry it's so small..

Here is a link that might be useful: Riding LAwn Mower issues


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RE: Lawnmower is making loud metal on metal sound when started

Does the noise occur at an idle?
Is the noise rotational - does it increase with engine speed?
With the engine at an idle try running the speed up rapidly. A loose con rod bearing will usually give a much sharper rapping sound under those conditions.


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RE: Lawnmower is making loud metal on metal sound when started

i'm sorry but if the noise is internal to the engine runnign it is ONLY going to make things worse. you need to pull teh engine and see what is going on, not jsut keep running it until it dies. and it likely will die soon. you could possibly still be able to rebuild it at this point, but once it tosses a rod thru the block you may be SOL.


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RE: Lawnmower is making loud metal on metal sound when started

Well wackylawnmowerman you still did not post the make and model number of the engine. It may surprise you to know Craftsman used more than one 10 hp engine. Craftsman 10 hp 5 speed doesn't tell anything.

But that is OK, perhaps others will help, I am out of here.

By the way, a noise loud enough to bring people out of the house to see if you are OK is not a connecting rod, it would have been gone long ago.

Walt Conner


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RE: Lawnmower is making loud metal on metal sound when started

Perhaps something in the starter mechanism is hanging up?
If so, it will manifest itself into a no-start condition
soon.


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