Toro 522xi Glowing Muffler Concern

[jmack 35]

I have a 522xi and noticed the muffler is glowing red as shown in this video? Should I be concerned and fix it to normal operating temps or is this expected?

 

Thanks,

JMack

[ineedanother 1,369]

I don't know that motor but would be concerned that you have a sticking valve. 

[8ntruck 6,998]

Maybe running too lean.  Might be possible that the muffler is blocked.

 

What kind of work are you doing when the muffler is glowing?  

[jmack 35]

I’m only mowing with my 60” at a reasonable pace. The same day three small pieces of muffler baffles flew out the end, which could be the blockage. 
 

The muffler is extremely loud before and after I noticed the glowing issue. 

[jmack 35]

Just to see how fast it starts glowing today, it only took 2 minutes from a cold start. 

[ineedanother 1,369]

When exhaust valves don't seat properly, unburned fuel ends up in the exhaust and burns there. Others might have a better explanation but that has been my experience.

[Jeff-C175 7,199]

3 minutes ago, jmack said:

Just to see how fast it starts glowing today, it only took 2 minutes from a cold start. 

 

Sumpin def wrong there.  Often one can see a dull red glow at night.  Never in the daylight, and never that bright red!

 

[jmack 35]

I’ll get it check out. Thanks!

[Snoopy11 5,714]

40 minutes ago, ineedanother said:

When exhaust valves don't seat properly, unburned fuel ends up in the exhaust and burns there.

Yep, that or an air/fuel ratio that is off.

 

In essence, it could be rather lean.

 

Don

[D_Mac 8,607]

The good news is that it's glowing red and not green and yellow !!! Just kidding !!! No good news about it. Hope you get it figured out. 

[953 nut 55,194]

14 hours ago, 8ntruck said:

Might be possible that the muffler is blocked.

 

14 hours ago, jmack said:

The same day three small pieces of muffler baffles flew out the end

 

14 hours ago, jmack said:

how fast it starts glowing today, it only took 2 minutes from a cold start

            Time to look at replacing the muffler.

[creighton trimble 8]

It is generally retarted ignition timing that causes the increase temperature that allows the exhaust to glow.

Yes , followed by lean air fuel mixture....

[jmack 35]

Good news!  Installed the new muffler and it purrs like a kitten again. It did appear the missing back pressure was the issue. 

[ineedanother 1,369]

2 minutes ago, jmack said:

Good news!  Installed the new muffler and it purrs like a kitten again. It did appear the missing back pressure was the issue. 

Great, but interesting...I really suspected a sticking valve. If it happens again, don't run it for long periods and overheat that side of the cylinder.

[Jeff-C175 7,199]

12 minutes ago, jmack said:

missing back pressure

 

You think the lower back pressure was causing unburnt fuel to be 'scavenged' from the cylinder and finishing it's burn in the muffler? And/or possibly leaning out the mixture ? 

 

 

[Snoopy11 5,714]

12 hours ago, jmack said:

Installed the new muffler and it purrs like a kitten again. It did appear the missing back pressure was the issue.

I have... honestly never heard of this. I run engines with no muffler at all... and the eggy-mani-folds don't glow...

 

Normally I err on the rich side 'cause I am a bit anal retentive about cylinder head temperatures...

 

Don

Edited August 23, 2022 by Snoopy11

[kpinnc 12,007]

That looks like a V-twin Kohler. If it is, you might want to check your valve clearances. You should be able to do it without removing anything more than those "OHV" covers.

 

Most V-twins with overhead valves require checking and adjusting valve clearance every 100 hours or so. 

 

 

[sngguns 1]

Where did you get a replacement muffler?

 

[Wild Bill 633 845]

On 8/28/2022 at 11:23 PM, kpinnc said:

That looks like a V-twin Kohler. If it is, you might want to check your valve clearances.

FYI, Kohler Commands have hydraulic lifters and thus there is no valve clearance/adjustment. In fact, you torque rocker arm screws with the rockers off of the valves and then position the rockers onto the valve after torqueing.

[Sailman 1,291]

On 8/22/2022 at 10:41 PM, jmack said:

Good news!  Installed the new muffler and it purrs like a kitten again. It did appear the missing back pressure was the issue. 

 

Interestingly enough on a V twin Harley engine increased back pressure in the mufflers enriches the air fuel mix and lack of back pressure leans out the engine. Sounds like the kohler engine is super sensitive to that.

[RED-Z06 2,221]

Ive noticed a number of engines get glowing mufflers, you dont notice much in the light but later in the evening you'll see it more.  I have an old beater 50" Cub Cadet Z Force with a 23hp Command, the cylinder type muffler will be a dull cherry in low light, my C100 will glow a good bit of the Donaldson muffler while mowing.  The onans seem to use a thicker muffler and flatheads have less compression..dont tend to have quite as high of EGTs, they will cherry up right at the inlet pipes.

 

After a hurricane well run generators for days at a time at 75% or more load..whole exhaust bright red...never have problems with them.

[jmack 35]

On 4/22/2023 at 5:07 AM, sngguns said:

Where did you get a replacement muffler?

 

Amazon but they’re out of stock now.