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.

 

[hemitom]

It looks like the governor is not hooked up, it's running wide open which will shake everything to death.

Turning up the speed seems like a good idea at the time but it makes them guzzle gas and eventually throw the rod.

You can add washers so the bolts catch on the broken holes in the shroud cover. As others said, that part is essential for proper cooling.

In the first video first thing I thought ! its running way to fast

 

[Fattylocks]

Those flat head Briggs are hard to kill but it's almost there.

 

[97prizm]

That’s not good.

I did try to restart it. I can’t seem to do so.

I pulled the plug. Nothing to see there. Original plug btw.

View attachment 171037View attachment 171038View attachment 171039

How would overheat correlate to the dieseling?

And now that it won’t seem to start, despite fuel and air and I expect a good start, it means what? The start with both the rope and when I put the cover back on and use the recoil starter, feels the same as it ever was.

Somebody mentioned a head gasket. If the timing is off or the ignition module is bad this can happen. I think my ignition module is going bad as it will only run till it gets hot then sputters.

 

[JHZR2]

Those flat head Briggs are hard to kill but it's almost there.

You realize this thread is OLD now, right?

Had I been able to find an engine with a rusted deck, I would have swapped it.

Instead I started an antique JD and Snapper Hi Vac collection. All good now!