Return of the Son of Lawnmower, Part II
This is the same Toro walk-behind gas mower you guys schooled me on at the beginning of the season. I got it running really well following y’all’s advice.
But today… after the first area I mowed, I shut ‘er down… and there’s a distinct ‘knock’ as it quit. During the second area, I ran into a tough spot and bogged it down a little, and it knocked hard and belched some blue/white smoke, before recovering. Same thing the rest of the afternoon: ran OK in the flat areas, but hit a spot of deep grass (i.e. overgrown edges, etc) and it bogged down badly, smoked nastily, and then recovered.
I figure something about the hard work is pushing oil into the cylinder and the bogging down is the caused by the oil burning off… poor combustion.
This thing’s 5 years old and I have used it fairly hard each year… mow a very cut-up half acre with it and hit my share of roots and rocks. There’s a nice rust hole in the deck that spouts clippings at me. I was hoping to finish the season with it (3-4 more times) and then scrap it, thinking the deals will be had during the winter.
Or maybe it just needs half an hour with someone who knows??
Replies
Put some Slick 50 in it, it works might get thru the summer.
Flywheel or blade could be loose.
David,
I would check the flywheel key. They act as a sheer pin when you hit something so the crank doesn't break.
KK
My thoughts too. If they shear off, the flywheel can move and change the timing, which will make it run bad or not at all. The knocking could be a result of the flywheel being loose, or from the timing being off.I hit a big rock with my old mower, which nearly broke my shinbone. It knocked me off my feet, and severely bruised my shin. It also bent the blade half way around, and sheared the flywheel key. I put a new blade on it and started it, but the crank was bent too. Out to the curb...
Dam,I have seen them just loose enough to change timing. Man those fylwheels are a booger to get off sometimes. I'm thinking that when his mower loads up the flywheel shifts enough so it's firing with the exhaust valve open.KK
Little bit of oil inside the air filter housing also. That change the diagnosis?
Maybe. Is the oil level too high from a stuck needle? Oil smell like gas? Remove the pull rope cover. Grab the flywheel and the blades and see if they are in sync, No slop or can you make it click-knock? Time for me to go nite nite. KK
Sounds like time to see about making a deal on a leftover mower. Deals start showing up soon.
You may have a scored cylinder and possibly a broken piston ring. The cylinder may be scored and a piston ring partially frozen or frozen in one spot.
You may also have a scored connecting rod. In most cases it is cheaper to order a short block that to repair the engine if there is a major problem.
Oil problems could be due to worn valve guides. It is very hard to say what the problem is until you open the engine up.
A good sign of what is wrong when you pull the rope and check the compression.