Repairs Where is the air filter on a Troy-bilt, z-start, 6.75 HP, 21" mower

My dad passed away recently & we can't figure out where the air filter is on his Troy-Bilt, z-start, 6.75 HP, 21" mower. We mowed with it all last year with no problems, this year it starts well first pull, but won't stay running...We've cleaned or replaced everything but can't figure out where the air filter is to replace it. Mower is evidently auto-choke, auto-prime. Very clean & well cared for, new spark plug, new oil, new gas. We've mowed 2x a week for the past month & a half & each time have to play with it for hours, let it set in the sun a while before it will continue to run once started. We are in Florida. We are 2 women, my daughter who is 42 & myself who is 72...I've always done my own yard & maintained my own mowers & have never had a mower where I couldn't find the air filter to replace it...We think this might be the problem. Any help would be greatly appreciated. It's a great little mower otherwise. Thanks for any suggestions or help & we will follow up on all suggestions. Thanks muich, Carol

I did a little searching on the web but couldn't find a z-start so we'll need more information from you. Start with the model number of the mower. After you find that, look for the engine model, type and code numbers as they are usually stamped on some part of the engine such as the blower housing, valve cover, etc. Look for the numbers and please take pictures from the top and all four sides so we can have a better view of what you are working on.

Thanks Lawnranger, It's dark outside now so tomorrow will get the model number & try to find someone with a cell phone camera to take some pics. Will get back to you then.

Is called Zstart though I think the Green around the Z might be supposed to be an E. Whatever its a Quantum. The air filter should be opposite the muffler on the other side of the engine under a cover that looks a bit like a mans wallet. Take the screw off and the cover and filter will come off the carb.

Thanks very much for your answer ...air filter is on opposite side from the muffler & the need for the model number...

The model # is 12AV566N711 & underneath that are the numbers 183621. Sorry, I don't have a camera to take pics...would have my grandson do it for me but he's on vacation. I do where it is now (on opposite side of the muffler) but it's been pouring rain here in Florida, all yesterday & today & just was able to get out there to get the model number. Sorry guys, I'm old & the ole eyes are not what they used to be... We'll investigate the air filter tomorrow & hopefully that will do the trick. I thank you all so much for this info...It starts right up each time so let's hope it continues to run once the air filter is taken care of With all this rain, the grass is growing as we speak