Is my flathead Briggs dead?

[AandPDan]

If it has an air vane governor that won't work without the shroud either. It probably was running fast.
Most mowers don't run at 3600 rpm, it depends on the blade length - tip speed and all.

 

[JHZR2]

It didn’t run any different yesterday versus the past many years. As I think about it, I’ve seen smoking from it before. Not this much though unfortunately.

 

[wpod]

A bent crank shaft is the most likely cause for a vibration.

Do the crankshafts bend on their own?

 

[spasm3]

I just mowed with it today. I do t think it’s as bad as the video makes it look. Obviously something is vibrating though…



yes not very large/long, this is suburbia, but it’s about 45…


How would I check that? I think it has a spring loaded thing on the carb, right?



I would say you’re on to something. A number of years ago it wasn’t running as I thought it should, I checked everything over, and believe it ran faster after. But I didn’t change anything that I’m aware of. What shoukd I check?

Check speed with one of these. Amazon for around $15.

 

[Lubener]

Do the crankshafts bend on their own?

When you hit something.

 

[Gyro Gearloose]

Do the crankshafts bend on their own?

They bend when you hit something like a stump or snag a root with the blade. My coworker hit an axe laying in the grass and not only bent the crank but he cracked his crankcase. The mower and his underwear were a total loss.

 

[spasm3]

Here is a link about straightening crankshafts. He starts out with whacky skits, but his info is good. Info starts at the 2:20 mark.

 

[JHZR2]

They bend when you hit something like a stump or snag a root with the blade. My coworker hit an axe laying in the grass and not only bent the crank but he cracked his crankcase. The mower and his underwear were a total loss.

I don’t know that I’ve hit a root but we do have a lot of maples around that push roots up, and somewhat irregular heights between grass and sidewalk.