Please help me purchase a new mower to mow 1/2 acre. I have specific requirements.

[Alaska_Guy]

No arguement from me. I have learned that by allowing my mower to idle for a few minutes before shutoff reduces the chances of backfire. My dealer instructed me to shut it off at full throttle. I have heard several mechanics and others on this site say the same. It just doesn't seem right to me. Here we go again. Sorry Alaska guy :smile:

This would have been great info for me yesterday. I let it idle for a minute or so before shutting off but it still backfired. Lesson learned. I will know what to do today after I am done mowing the back yard.

I also went out and purchased a STIHL 50 CE weed wacker today. I tore my shoulder and this thing should make starting it much easier.

On a side question.....

Would this unit be worth buying for just snowblowing?

Tractor + Snowblower

 

[Carscw]

All mowers are designed to run at full throttle.
The engine stays coolest and cools down faster at full throttle. Letting a engine run at a idle for 5 mins will make it run hot.

Driving a mower that is a hydro drive at less then full throttle will shorting the life of the hydros.

Think about it. The faster the fan turns the more air it moves.

 

[1striper1]

All mowers are designed to run at full throttle.
The engine stays coolest and cools down faster at full throttle. Letting a engine run at a idle for 5 mins will make it run hot.

Driving a mower that is a hydro drive at less then full throttle will shorting the life of the hydros.

Think about it. The faster the fan turns the more air it moves.

Jesus H read what I typed. I said park it, let the engine idle for a few minutes. So the Tecumseh, B&S and Kohler engineers that I know are wrong when they ALL say that shutting down a HOT air cooled engine is the worse thing you can do for it?

I have been following this advice on all of my air cooled engines since the 80's and I wonder why my 95 B&S Vanguard V-Twin has near stock compression. I know...it's an anomaly.

 

[1striper1]

This would have been great info for me yesterday. I let it idle for a minute or so before shutting off but it still backfired. Lesson learned. I will know what to do today after I am done mowing the back yard.

I also went out and purchased a STIHL 50 CE weed wacker today. I tore my shoulder and this thing should make starting it much easier.

On a side question.....

Would this unit be worth buying for just snowblowing?

Tractor + Snowblower

It's probably worth $500 if you part it out. Heck, for $200 if it runs now you have very little to lose!

If it backfires no matter your idle speed at shutdown, don't worry about. It's a little raw gas getting into the muffler then igniting.

Did you get some Mechanic In A Bottle yet?

Did you go to the airshow at Ted Stevens last weekend? I heard it was great!

 

[Shughes717]

All mowers are designed to run at full throttle.
The engine stays coolest and cools down faster at full throttle. Letting a engine run at a idle for 5 mins will make it run hot.

Driving a mower that is a hydro drive at less then full throttle will shorting the life of the hydros.

Think about it. The faster the fan turns the more air it moves.

The faster the engine runs the more combustion occurs as well which creates more heat. Energy cannot be created without creating heat. The reason the fan runs faster is because the engine is creating more heat at higher speeds and needs more air to prevent the engine from over heating and shutting down. It doesn't mean the engine is running cooler at high rpm. You are a race car guy. Your car runs around the track at a high speed and high rpm. Lots of air coming in. Is the engine cool when you pull into the pits? Farm Tractors are made to run at full throttle as well, but you still have to let them idle to cool before shutting them off (yes I know tractors have Diesel engines, but the same principles apply). I just found that by letting mine idle for a few minutes helps prevent backfire. I do agree that you should only move a hydrostatic mower at full engine throttle though.

 

[Shughes717]

This would have been great info for me yesterday. I let it idle for a minute or so before shutting off but it still backfired. Lesson learned. I will know what to do today after I am done mowing the back yard.

I also went out and purchased a STIHL 50 CE weed wacker today. I tore my shoulder and this thing should make starting it much easier.

On a side question.....

Would this unit be worth buying for just snowblowing?

Tractor + Snowblower

Where I live I don't have much use for a snow blower, but it looks like someone put a lot of thought into it.

 

[1striper1]

Where I live I don't have much use for a snow blower, but it looks like someone put a lot of thought into it.

Where I live we usually get lots of snow. If I could find this setup in my area and could get a year or two out of it, it'd be a steal. These setups in my area are at least $1000 in good running condition.

 

[Alaska_Guy]

Well, missed my opportunity. Someone else snagged it!

I didn't make it to the air show. I have lived here over 30 years and I just don't do that kind of stuff anymore. I didn't get the snake oil.... I really don't believe in 99.9% of that stuff.

 

[bertsmobile1]

The faster the engine runs the more combustion occurs as well which creates more heat. Energy cannot be created without creating heat. The reason the fan runs faster is because the engine is creating more heat at higher speeds and needs more air to prevent the engine from over heating and shutting down. It doesn't mean the engine is running cooler at high rpm. You are a race car guy. Your car runs around the track at a high speed and high rpm. Lots of air coming in. Is the engine cool when you pull into the pits? Farm Tractors are made to run at full throttle as well, but you still have to let them idle to cool before shutting them off (yes I know tractors have Diesel engines, but the same principles apply). I just found that by letting mine idle for a few minutes helps prevent backfire. I do agree that you should only move a hydrostatic mower at full engine throttle though.

Your logic is both right and wrong.
Yes running at full speed does generate more more heat.
However the rate that the heat is transferred to the engine rather than blown out the exhaust is directly proportional to the time the hot gasses are in contact with the cylinder / head piston & valves.
This heat transfer rate is called the R value, the said same R value that you are used to for rating insulation
And to bring it into focus, aluminium melts at 700 deg C dut your cylinder reaches 1800 deg C why does the piston not melt ? or for that matter the inside of the head ?
So the faster you get the gasses out the less heat will be transferred to the engine.

You have obviously never had much to do with old long stroke vintage engines which will happily sieze at speeds well under 1000 rpm.
It is also one of the reasons why you have more exhaust port than inlet port.

Then there is the volumetric efficiency of the fan, the higer the fan speed the more efficient the fan and the volume of air moved per revolution of the fan actually increases substantially till its viscious limit.

So at higher speeds you are getting more air per BTU and increased cooling efficiency.
Yes there is more heat being generated but it is being transferred to the engine at a decreasing rate and being removed by the air at an increasing rate.
And before some clot makes an idiot extrapolation, no, it won't eventually freeze like all physical matters there is a limit all thermal graphs are curves

And then there is the internal cooling being done by the oil and the volume efficency of the oil transfer system and residual oil to consider.
Running a Vertical shaft engine too slow will reduce the volume of oil at the top bearing because at slower spees the oil drains through the top bearing a lot faster because the gravity forcing the oil doen is not fighting against the centrifugal force trying to fling the oil out onto the bushing wall.

So funny enough the engine companies actually have it right.

And as for some idiot reason people always have to bring in comparisons between things that are totally irrelevant .
Have a good look at the NAS Car videos of drivers comming into the pits.
Do they sit there and idle for 2 minutes before thay shut down or come in at full revs and switch strait off, Do they idle in a high gear to keep to pit lane speed limits so the engine is cooled down better or come in running hard in a low gear ?

And of course all of this is totally irrelevant but resorting to irrevelevance seem to be the norm now days.

 

[Shughes717]

Your logic is both right and wrong.
Yes running at full speed does generate more more heat.
However the rate that the heat is transferred to the engine rather than blown out the exhaust is directly proportional to the time the hot gasses are in contact with the cylinder / head piston & valves.
This heat transfer rate is called the R value, the said same R value that you are used to for rating insulation
And to bring it into focus, aluminium melts at 700 deg C dut your cylinder reaches 1800 deg C why does the piston not melt ? or for that matter the inside of the head ?
So the faster you get the gasses out the less heat will be transferred to the engine.

You have obviously never had much to do with old long stroke vintage engines which will happily sieze at speeds well under 1000 rpm.
It is also one of the reasons why you have more exhaust port than inlet port.

Then there is the volumetric efficiency of the fan, the higer the fan speed the more efficient the fan and the volume of air moved per revolution of the fan actually increases substantially till its viscious limit.

So at higher speeds you are getting more air per BTU and increased cooling efficiency.
Yes there is more heat being generated but it is being transferred to the engine at a decreasing rate and being removed by the air at an increasing rate.
And before some clot makes an idiot extrapolation, no, it won't eventually freeze like all physical matters there is a limit all thermal graphs are curves

And then there is the internal cooling being done by the oil and the volume efficency of the oil transfer system and residual oil to consider.
Running a Vertical shaft engine too slow will reduce the volume of oil at the top bearing because at slower spees the oil drains through the top bearing a lot faster because the gravity forcing the oil doen is not fighting against the centrifugal force trying to fling the oil out onto the bushing wall.

So funny enough the engine companies actually have it right.

And as for some idiot reason people always have to bring in comparisons between things that are totally irrelevant .
Have a good look at the NAS Car videos of drivers comming into the pits.
Do they sit there and idle for 2 minutes before thay shut down or come in at full revs and switch strait off, Do they idle in a high gear to keep to pit lane speed limits so the engine is cooled down better or come in running hard in a low gear ?

And of course all of this is totally irrelevant but resorting to irrevelevance seem to be the norm now days.

This is probably going to offend you, but I can't ask without it seeming offensive. Can you post on a thread without typing a novel? Way too long. Apparently it's done in an attempt to prove you are more intelligent than everyone else, but it's too much to read. Engines run on the same principles of combustion. I understand what your points are, but the engine temperature on a car increases faster when it's going down the road at a higher rpm than it does sitting in your driveway idling. The same principles should apply to smaller engines such as mower engines.

Btw bertsmobile you are also partially right. I haven't been around any long stroke gas engines, but I have been around plenty of old Diesel engines such as the old long stroke engines on a popping john tractor which also should be idled before shutting off. Have antique tractor pulls in my area frequently. This is a topic that is going to be argued by several. No ones opinion will change from this, so I will leave it alone from now on.