Why do mowers have primer bulbs?
 

seems simple enough.
a bulb is cheaper.
bulb requires fewer parts in the carb. fewer parts mean less cost.
craftsman have bulb. cheap
Honda does not have bulb. not cheap

Frank

Why do mowers have primer bulbs?
 

I mowed 2 1/2 acres last year 10 days after a c-section with an
ANCIENT rebuilt 3.5 hp........


Wow. Were you hit from behind by a Harley?

That must have been a painful birth.



LMAO..that was a pretty stupid way of wording that, huh....LMAO!

hehe - you're a good sport!

I hope you and the twins (briggs & stratton) have a great life ;)

Why do mowers have primer bulbs?
 

wrote:

seems simple enough.
a bulb is cheaper.
bulb requires fewer parts in the carb. fewer parts mean less cost.
craftsman have bulb. cheap
Honda does not have bulb. not cheap

Frank

Poor mainframe can't get an answer to his question.
Here ya' go. The old carburators allowed the heat of the day
to push fuel through the engine when not running. This fuel
evaporated into unnecessary pollution. It would also (sometimes)
flood the engine and make it hard to start. The new carbs, in order
to comply with emissions standards, do not allow this fuel to be
pushed through. In exchange for that, you need to prime the
engine with the bulb.
HTH

Why do mowers have primer bulbs?
 

"John Harlow" wrote in message
...

I mowed 2 1/2 acres last year 10 days after a c-section with an
ANCIENT rebuilt 3.5 hp........


Wow. Were you hit from behind by a Harley?

That must have been a painful birth.



LMAO..that was a pretty stupid way of wording that, huh....LMAO!

hehe - you're a good sport!

I hope you and the twins (briggs & stratton) have a great life ;)

Sounds like the names of a pair of Brittish butlers.

Why do mowers have primer bulbs?
 

Amy D wrote in message ...

[...]
But...did the OLD mowers have to mix oil and gas? Just curious.....


Mixing gas and oil implies a 2-cycle engine. The only old 2-cycle
mower that I'm aware of were the old Lawnboys (usually lime green in
color). Other than that 2-cycles are mostly seen on trimmers and
chainsaws.

Why do mowers have primer bulbs?
 

"Larry" wrote in message
...

"Mainframe" wrote in message
...
I may be in the market for a new lawn mower.

But, I have notice that evey mower (except for Hondas) have this bulb
that
has to press at lease 3 times before starting the engine.

Why?

You'll also notice they do not have a 'choke' (that can inadvertently left
on).

Emission controls, thanks to the EPA.


(¯`·._.· £ãrrÿ ·._.·´¯)


Maybe for the same reason that outboard engines on boats have bulbs...
Different type of carburator..

Just a thought.

Gr,
I

Why do mowers have primer bulbs?
 

[posted and mailed]

"Mainframe" wrote in
:

I may be in the market for a new lawn mower.

But, I have notice that evey mower (except for Hondas) have this bulb
that has to press at lease 3 times before starting the engine.

Why?

And why not Hondas?

Is this an anti-pollution device?

Has lawn mower engine design change that much?

I remember when all you had to do is fill the tank with gas, make sure
that the oil was full, and pull the cord.

It reminds me of the days before fuel injection in cars.



The primer bulb is there for many reasons.

As someone else indicated, a primer is CHEAP, and generally very reliable.

For many years, Briggs and Stratton had an automatic choke on most of
their walk behind mower engines. This automatic choke had many problems
over the years, and was not always reliable. Further, it often OVER
choked, or flooded a hot engine.
Tecumseh had a different idea, they designed a "self-priming" carburetor.
It, too, didn't always work as planned, and was often retrofitted with a
rubber primer bulb on the BOTTOM of the carburetor bowl. Tecumseh
eventually moved the primer bulb to the side of the carburetor and
eliminated the "self priming" feature of their carburetor. Briggs and
Stratton replaced their own auto-choke carburetor with one licensed from
Walbro that had a manual choke, which worked well except for the fact that
many people left the choke on after starting. This created "excess" air
pollution. That Walbro carburetor is the basis for the newer version with
the primer as well.

Despite the fact that over 90% of the air pollution from lawn and
garden equipment comes from spilled or evaporated fuel, the government
has imposed "tailpipe" emission standards on all outdoor power equipment
engines. So many of the manual chokes have disappeared. Honda still uses
a manual choke because their engine runs very lean and their choke is
partially self relieving. This means the choke opens itself partially once
the engine is running. Both Briggs and Stratton and Tecumseh still offer
the mower manufacturer the option, for an additional charge, of a choke on
a very small number of engine models, but the equipment manufacturers
generally don't spend the extra money.

Rider mower engines are different. They all still have chokes, either as a
part of the throttle control, or as a separate control. Since you have to
be in the seat to start and run a rider, it would be difficult to use a
primer on these (not impossible, but nearly). Kohler has actually begun
offering electronic fuel injection (Honda does NOT as yet) on rider mower
engines. I believe that eventually all riders will have EFI just like all
cars have had since the mid-80's.

The EPA rules are also why you are beginning to see 4 cycle line trimmers
on the market. 2 cycle engines, where you mix the oil into the gas, are too
dirty to meet the rules for most application. And California, as always, is
leading the way to even stricter rules.

I believe that eventually the hand held equipment will be almost entirely
rechargeable electric in a few years, with the only forseeable exception
being chain saws. It could well pass that even the walk behind consumer
mower market could end up all rechargeable as well. After all, GE sold
rechargeable GARDEN TRACTORS from around 1969 to 1974. They sold the entire
product line to Wheel Horse, who conitnued to sell them until 1981 or '82.
They are highly collectable today.

Matt

Why do mowers have primer bulbs?
 

"Matt" wrote in message
...
[posted and mailed]

"Mainframe" wrote in
:

I may be in the market for a new lawn mower.

But, I have notice that evey mower (except for Hondas) have this bulb
that has to press at lease 3 times before starting the engine.

Why?

And why not Hondas?

Is this an anti-pollution device?

Has lawn mower engine design change that much?

I remember when all you had to do is fill the tank with gas, make sure
that the oil was full, and pull the cord.

It reminds me of the days before fuel injection in cars.



The primer bulb is there for many reasons.

As someone else indicated, a primer is CHEAP, and generally very reliable.

For many years, Briggs and Stratton had an automatic choke on most of
their walk behind mower engines. This automatic choke had many problems
over the years, and was not always reliable. Further, it often OVER
choked, or flooded a hot engine.
Tecumseh had a different idea, they designed a "self-priming" carburetor.
It, too, didn't always work as planned, and was often retrofitted with a
rubber primer bulb on the BOTTOM of the carburetor bowl. Tecumseh
eventually moved the primer bulb to the side of the carburetor and
eliminated the "self priming" feature of their carburetor. Briggs and
Stratton replaced their own auto-choke carburetor with one licensed from
Walbro that had a manual choke, which worked well except for the fact that
many people left the choke on after starting. This created "excess" air
pollution. That Walbro carburetor is the basis for the newer version with
the primer as well.

Despite the fact that over 90% of the air pollution from lawn and
garden equipment comes from spilled or evaporated fuel, the government
has imposed "tailpipe" emission standards on all outdoor power equipment
engines. So many of the manual chokes have disappeared. Honda still uses
a manual choke because their engine runs very lean and their choke is
partially self relieving. This means the choke opens itself partially once
the engine is running. Both Briggs and Stratton and Tecumseh still offer
the mower manufacturer the option, for an additional charge, of a choke on
a very small number of engine models, but the equipment manufacturers
generally don't spend the extra money.

Rider mower engines are different. They all still have chokes, either as a
part of the throttle control, or as a separate control. Since you have to
be in the seat to start and run a rider, it would be difficult to use a
primer on these (not impossible, but nearly). Kohler has actually begun
offering electronic fuel injection (Honda does NOT as yet) on rider mower
engines. I believe that eventually all riders will have EFI just like all
cars have had since the mid-80's.

The EPA rules are also why you are beginning to see 4 cycle line trimmers
on the market. 2 cycle engines, where you mix the oil into the gas, are
too
dirty to meet the rules for most application. And California, as always,
is
leading the way to even stricter rules.

I believe that eventually the hand held equipment will be almost entirely
rechargeable electric in a few years, with the only forseeable exception
being chain saws. It could well pass that even the walk behind consumer
mower market could end up all rechargeable as well. After all, GE sold
rechargeable GARDEN TRACTORS from around 1969 to 1974. They sold the
entire
product line to Wheel Horse, who conitnued to sell them until 1981 or '82.
They are highly collectable today.

Matt


Thanks for the info.