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Engines seize up

#1

O

oldcoot

I have two mowers in my shop right now that after you mow for a while and shut it down to dump bag, drink a beer or whatever the engine is seized up. You can grab the blade and break it loose easily and they run fine. Both engines are the cheaper briggs with the plastic carb, one is on a Husqvarna and one is on a Craftsman with about 3 hours on it. I suspect that the big end of the rod is heating up and seizing to the crank. I understand that the rods are aluminum with no bearing inserts. Any help would be appreciated. Thanks in advance


#2

Scrubcadet10

Scrubcadet10

Did you check your oil level? are you using the correct weight oil? i would imagine it's SAE 30.


#3

O

oldcoot

Yes and yes


#4

Fish

Fish

Not Dollar General oil?


#5

cpurvis

cpurvis

One of your basic assumptions is wrong. As circular items, such as the rod journal, heat up, the inside diameter gets bigger, not smaller.

So let's consider other things that could lock up your engine, which was running fine right up to the point of being shut off. I'd take off the shroud and clean the cylinder fins.


#6

S

slomo

Those new Briggs engines never need oil changes LOL. This is not an oil issue LOL.

slomo


#7

O

oldcoot

cpurvis said:
One of your basic assumptions is wrong. As circular items, such as the rod journal, heat up, the inside diameter gets bigger, not smaller.

So let's consider other things that could lock up your engine, which was running fine right up to the point of being shut off. I'd take off the shroud and clean the cylinder fins.
Click to expand...


#8

O

oldcoot

You are absolutely right and due to differing rates of linear expansion the crank journal would not grow as much as the ID of the rod bore, sorry bout that The cylinder cooling fins are clean as these are both low hour engines and I don't know about the oil but they are both clean and on the mark


#9

tom3

tom3

That's the weirdest thing I've heard of on a mower. Recoil starter grabbing on shut down? Maybe a ball of twine around the crankshaft at the bottom?


#10

Hammermechanicman

Hammermechanicman

I would pull the shroud and check the brake. If something was binding in the engines they would have failed.


#11

B

bertsmobile1

Run one and let it cool down & bind
Then remove the blower housing which will exclude hings like a starter pawl jambing
I did have one mower come in where they had ben spraying the brake block with WD 40 .
That has caused itto become soft & sticky when hot.
Thankfully they are not law down here so I can just rip them off.
There is no way the brake can prevent injury on a mower more than 1 season old as the pads wear & take a dozen revolutions to stop he engine by which time all your toes are dog food ./
If one is stupid enough to mow bare foot, in thongs or shove your hand into the blades then you deserve to be hurt badly .
The missing fingers / toes will serve a useful purpose to remind you that mowers are dangerous.


#12

C

Cfs

I have a craftsman with a Briggs that is doing the same exact thing..shut it down hot and it dies not want to restart. Starter rope will not pull turn the blade underneath a few times and it frees up


#13

S

slomo

Cfs said:
I have a craftsman with a Briggs that is doing the same exact thing..shut it down hot and it dies not want to restart. Starter rope will not pull turn the blade underneath a few times and it frees up
Click to expand...
Pull the oil dipstick and smell for fuel. If you detect gas, fix the carb needle/seat. Once carb is repaired, dump your oil a few times.


#14

S

slomo

Fish said:
Not Dollar General oil?
Click to expand...
What's wrong with DG oil? Do you think DG really makes their own oil? Probably made by Amsoil.


#15

S

slomo

cpurvis said:
I'd take off the shroud and clean the cylinder fins.
Click to expand...
You lost 99.98% of all humans on this planet. Can you elaborate on this please? (y)


#16

sgkent

sgkent

thinking about it, the engine may be so hot that the oil is flashing off and causing the piston to stick to the cylinder. Try a better oil and don't run it so hard. Make sure all the cooling fins are clean as is the fan.


#17

S

slomo

sgkent said:
thinking about it, the engine may be so hot that the oil is flashing off and causing the piston to stick to the cylinder. Try a better oil and don't run it so hard. Make sure all the cooling fins are clean as is the fan.
Click to expand...
Fins and his oil are fine as he stated.

For oil to flash off, the temp would be 450F and above. As in engine meltdown mode.

Hydrolock hydrolock hydrolock. Plastic carbs. Cheap mower alert!


#18

Fish

Fish

slomo said:
What's wrong with DG oil? Do you think DG really makes their own oil? Probably made by Amsoil.
Click to expand...

Dollar General Motor Oil Lawsuit Settlement Reached

Dollar General has agreed to settle a motor oil lawsuit which alleges DG Auto SAE 10W-30 and 10W-40 oil sold between 2010 and 2017 is obsolete and harmful for vehicle engines made after 1988. The motor oil class action also alleges Dollar General Auto SAE 30 oil can't be used in engines...
www.carcomplaints.com


#19

sgkent

sgkent

never had oil cook into a solid in the stove or on a pan? VW heads are aluminum and they run 450F all the time. They also get coated on the valve side with varnish from the heat. I don't think the binding is mechanical. Hydrolock can happen but we are talking several different models here. And once the blade is wiggled they start fine. A hydolocked engine would take a lot more than wiggling a blade to start it. For one it would take a while to dry out the cylinder to where it could even fire.


#20

S

slomo

sgkent said:
VW heads are aluminum and they run 450F all the time.
Click to expand...
VW heads don't have oil circulating inside them unless I'm missing something. Maybe they do. Head temp and oil temp are different. If and oil gets over 300F look out. Definitely time for a cooler.
sgkent said:
A hydolocked engine would take a lot more than wiggling a blade to start it. For one it would take a while to dry out the cylinder to where it could even fire.
Click to expand...
Assuming said engine has a 0% zero leak down figure to it. On theses old tired mower engines I doubt it. Possible yes.


#21

S

slomo

sgkent said:
never had oil cook into a solid in the stove or on a pan?
Click to expand...
I'm not allowed in the kitchen anymore. My 5 foot 0" wife won't allow it LOL. o_O


#22

sgkent

sgkent

The point is that to hydrolock something one needs to fill the cylinder with a fluid. Just wIggling the blade is not going to make it go from hydrolocked to ready to pull with a rope and start.


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