Catalytic converter for a 24 hp grass cutter ?

[Edwin Dirnbeck]

Has anyone put a catalytic converter on an old school 24 hp air cooled Kohler engine. I mow about 3 hours and am not likeng the smell . I guess in the good old days, the smell was allways hanging in the air in metro areas and you just didnt notice it. Just like cigarette smell. Edwin Dirnbeck.

[polaraligned]

Love that smell....How about just routing the exhaust so it is exiting behind you?

[Tim Clarke]

Have you tried adjusting the carburetor? might be running a little rich.

[ikdor]

The converter won't fix your mixture. If there's no computer to measure the fuel to air ratio you need forced ventilation into the exhaust to bring the extra oxygen, and an overly rich mixture can then melt your converter. It'll smell better until that point though :-)

[BCRider]

The only thing that converters do is slightly change the smell. I've got motorcycles that are running at their best mixture but no converters and the car and truck with converters. They all stink if the exhaust gets in my face. Just in a different way. The converters seem to give it a slightly ammonia like smell.

I'd say that polaraligned has the best suggestion. But instead of just pointing it a different way I'd consider running a taller stack up so it discharges upward where the breeze will aid with mixing and taking it away. If you just point it in a different direction down low then at some point the discharge will be directly upwind of you in the saddle and it'll still be in your face.

I'm thinking that if you try the vertical pipe it should be roughly head height or just a whisker more. That way when you're seated it'll be fairly well above your head.

[JRouche]

Has anyone put a catalytic converter on an old school 24 hp air cooled Kohler engine. I mow about 3 hours and am not likeng the smell . I guess in the good old days, the smell was allways hanging in the air in metro areas and you just didnt notice it. Just like cigarette smell. Edwin Dirnbeck.

Cat converters are not air fresheners. They wont work in your situation. Your air cooled Kohler will melt it and then restrict the exhaust gases. Tune the engine up. Carburetor maintenance used to be a thing before many things went to EFI. Get a rebuild kit for the carb, change the oil, check the entire exhaust system for leaks or blockage. You know, just regular maintenance. The Band-Aid you are looking for is not a catalytic convertor. JR

[old mart]

Unfortunately, you need other parts in a cat system besides the cat for it to work.

Electronic engine management system
fuel injection
oxygen exhaust analyser

And thats about the minimum needed.

My Suzuki Burgman 400 is 33 hp, here is the schematic for the emission control.

[Edwin Dirnbeck]

The converter won't fix your mixture. If there's no computer to measure the fuel to air ratio you need forced ventilation into the exhaust to bring the extra oxygen, and an overly rich mixture can then melt your converter. It'll smell better until that point though :-)

THANK YOU, This is the kind of information that I am looking for.Edwin Dirnbeck

[Mark Rand]

Get a few sheep???

[tom_d]

Get a few sheep???

A few sheep? If you think the engine exhaust smells too much...........

[projectnut]

The only thing that converters do is slightly change the smell. I've got motorcycles that are running at their best mixture but no converters and the car and truck with converters. They all stink if the exhaust gets in my face. Just in a different way. The converters seem to give it a slightly ammonia like smell.

I'd say that polaraligned has the best suggestion. But instead of just pointing it a different way I'd consider running a taller stack up so it discharges upward where the breeze will aid with mixing and taking it away. If you just point it in a different direction down low then at some point the discharge will be directly upwind of you in the saddle and it'll still be in your face.

I'm thinking that if you try the vertical pipe it should be roughly head height or just a whisker more. That way when you're seated it'll be fairly well above your head.

Be careful how high you make the exhaust stack and where you point the exit. I have a small end loader with a 22hp water cooled 2-cylinder Kawasaki engine. Originally the stack was slightly higher than the drivers head and pointed 90* from the body. It looked great and sounded awesome. Unfortunately, as the machine cooled down water would condense in the pipe and muffler. The next time the machine was started (didn't matter if it was 2 hrs. or 2 weeks later) it would spray black gunk all over everything in line with the exit end. Over the years I put black spots on the cars, trucks, tractors, and anything else that happened to be in the line of fire. I finally got tired of cleaning everything and rotated the pipe, so the exit end faces the ground. I now have an almost permanent black spot about a foot in diameter on the garage floor where it gets parked.

[I make chips]

Cats need a somewhat rich mixture to 'light them off'. With that in mind they need a fuel system control to provide a sweet spot of fuel air ratio for them to work. Too rich and they'll overheat and burn up. Too lean they go cold and do nothing. Although a lot of modern small engines are going with fuel injection these days which might provide that sweet spot for your cat.

I say effit, toss a cherry bomb muffler on it!

[JRouche]

Be careful how high you make the exhaust stack and where you point the exit. I have a small end loader with a 22hp water cooled 2-cylinder Kawasaki engine. Originally the stack was slightly higher than the drivers head and pointed 90* from the body. It looked great and sounded awesome. Unfortunately, as the machine cooled down water would condense in the pipe and muffler. .

Thats funny, not the exhaust, where you pointed it for fun.. Its no good. Thats stupid.

Yeah well, me too. My 62 Nova still sets all cars alarms off. parking lots.

Its a small engine, chevy 350 (1986). JR

Oh? I EFI-ed this one from the start..

That means I have no catalytic converters (old car).
I do have two independent Wide band O2 sensors along with their controller. Not the same company for controls. . JR

[Doozer]

Unfortunately, you need other parts in a cat system besides the cat for it to work.

Electronic engine management system
fuel injection
oxygen exhaust analyser

And thats about the minimum needed.

My Suzuki Burgman 400 is 33 hp, here is the schematic for the emission control.

I have owned many cars that were carbureted, no O2 sensors, and had converters.
I think your blanket statement is not true.

-D

[Willy]

I have owned many cars that were carbureted, no O2 sensors, and had converters.
I think your blanket statement is not true.

-D

Yes, same here.
Catalytic converters are available from a number of different sources for the use in various small engine applications.
Some are stand-alone units while others have the option to further optimize their efficiency by the use of an optional A/F controller as shown in the link below.

Below is just one example and a quote from their installation guide to give you some insight into the conversion.

https://www.nettinc.com/products/3-way-catalytic-converters/bluecat-small-spark-ignited-engines-emission-control

LPG/CNG/Gasoline Engine tune-up
The ignition/fuel system should be set to the manufacturer's specifications. BlueCAT™ SSI catalytic muffler works
optimally with a slightly-lean (within OEM specs) operation setting. Many OEMs offer high elevation kits together
with information on how to setup the engine to run slightly leaner. Refer to guidelines provided by OEM for best
practices.
To provide maximum CO, HC, and NOX conversions, Nett's BlueCAT™ 100 Air/Fuel (A/F) Ratio Controller should
be used with BlueCAT™ SSI catalytic mufflers on LPG/CNG engines, and the mixer should be set to a slightly-rich
mixture.