When mowing with the 60" MMM and hit a patch of common Bermuda the tractor smokes black. When I slow it down it will clear up. I know that is unburned fuel I guess what has me a little concerned is the height of the Bermuda causing the heavy load and wondering if this is common. I am cutting on the second hole on the wheels and the grass is not more than 4 more like 3 inches high. I'm just looking for a reality check here. I understand I am only working with 16HP and my last mower was a Ferris zero turn with the pro briggs eng was 28HP I think but the zero would run thru waist high Bahia with out slowing down. Any input comments are appreciated.
First lets talk about bermuda grass - as you know it is one tough som beeeauch!(jackie gleeson voice) the grass does not grow vertically - but horizontally and grow it does well!
you up in the rpm range? What is happening is that your engine is running at "x" rpm's and the fuel is appropriate for that rpm, and then you hit the tough stuff and the rpm's drop - but the fuel does not catch up fast enough, the governor is trying to bring the rpm's back up and so on.
blades good and sharp? your zero turn have a 5' cut?
I have the same machine as you do - and same MMM - i can feel the engine moan a bit when my grass goes from fescue to bermuda - and I fertilize the hell out of the bermuda!
sharpen the blades, raise the deck a bit , and cut slower ! See if it makes a difference!