Dying Mower?

[Melman]

Looking for some guidance on my old-ish Cub Cadet lawn mower. It has the B&S 6.5 engine, does not have the words 'Intek" or "Vanguard". "Professional Plus," maybe. Oil is full, changed annually with whatever 5w30 or 10w30 is closest at hand. Probably QSGB right now, SL grade.

Before I start any OPE, I always pull the rope a few times to verify easy turning before I yank my shoulder out. The last couple weeks with this mower, it's been making a grinding/scraping kind of sound. I thought it was clippings built up underneath so I scraped it as clean as I could after my last cut. Same noise this week. However, after I tickle the carb the usual 12-15 times, it starts on the first pull with the normal single blue puff it has made for the last 10-12 years. After done mowing, pull the cord slowly and no grinding noise.

Any ideas on some simple things to look at?

I like this simple mower. 6-speed RWD self-propelled. Single lever height adjust. No problems with anything except the grinding noise. I bought it as a closeout mower in 2004 or so.

 

[BrocLuno]

The fan screen where the flywheel is. Could be rubbing on the housing... Or something inside the housing could be rubbing... Or it could be a pulley loosing a bearing and starting to track off and rubbing?

Sometimes it's a good ide4a to pull the plug and shoot some light oil into the cylinder (MMO is one choice) and pull it over a few times. Helps loosen top ring and rebuild compression. I've had good luck with a healthy shot of Tri-Flow into the cylinder. Then re-insert plug and start it. Usually run a bit better for a while

 

[Lubener]

Couple things to check. They started putting brake pads which rub on the flywheel when you release the handle. Not sure if yours has one. Also, maybe the magneto may have loosened and intermittently rubs on the flywheel. Might want to pull the top cover and see and you can check the flywheel screen as previously posted.

 

[bubbatime]

Originally Posted By: Lubener
They started putting brake pads which rub on the flywheel when you release the handle.


There is your answer. The safety bar handle has a flywheel brake on it. Are you pulling the engine over slowly without depressing the handle?

If the engine runs fine and sounds fine while running, dont worry about it.

 

[Melman]

Thanks everyone.

Got to Mom's last night and used the mower. Depressed the brake blade handle and did the slow pull as usual to verify not seized. Made no grinding noises, pulled smoothly and started fine and ran great as usual. I was going to look in the screen area as suggested above but no noise, nothing to investigate. Might get the time next week to take a good look. Thought I would pay special attention to the flywheel brake pads and the release handle and cable.

I had a bad thought yesterday while mowing the looooong grass (lots of rain lately) and it sounding like the deck was clogging. I sometimes, like almost everybody in the free world, raise the front wheels then drop the mower to dislodge sticking grass from the deck. Could I be damaging the crankshaft bearings or something doing this? Maybe the bouncing dislodges the crankshaft enough that when I shut off in a couple minutes, it sits cockeyed until I next mow grass, then it makes the grinding noise until running the engine gets enough oil in there to make it stop grinding.

I'm still thinking flywheel brake, but I really like a good complicated theory!

 

[smancer]

Is your starter pull cord mounted to the handle? If so, does it have lots of slack? On some mowers if there's too much slack, the recoil mechanism moves just a tad too easy causing it to grind when the engine is running.

How does the blade look? With the spark plug disconnected, you can put your finger on the end of the blade while slowly turning it to see if it may be contacting the deck on certain spots. Maybe check the deck for any cracks too.