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Motor is wheezing, as if it's breathing - why?



 
 
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  #1  
Old May 5th 20, 06:46 PM posted to rec.autos.tech
Arlen Holder[_4_]
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Posts: 11
Default Motor is wheezing, as if it's breathing - why?

It's a Honda lawnmower I'm asking about, which is about 10 years old, but
which runs fine most of the time.

I replaced the plug, ran a tank of fresh gas, and cleaned the filter, and
yet, it "wheezes" like it's breathing, normal rpm, and then slower rpm and
then normal rpm and then slower rpm and then normal rpm and then slower
rpm, etc, ad infinitum.

The interval is only about a second or two at most for this
stoichiometric:lean stoichiometric:lean stoichiometric:lean cadence to
occur and the stoichiometric:leancycles are quite regular.

The (California) carb on this thing is not adjustable (AFAIK), and the
choke shuts off in seconds as it's merely a slider that glides back in
place in a couple of seconds after initial activation.

Even after a half hour of running, the stoichiometric:lean wheezing only
gets slightly less pronounced, where the stoichiometric:lean wheezing I'm
talking about is when there is no load (e.g., it's sitting level on a
sidewalk). (Under load, it's harder to tell, but there's no "speed"
adjustment given I have the throttle bar on the handle taped tight in the
always-full-on position.)

I'm thinking it's all in the carb - i.e., choke and/or throttle...

So I guess it "could" be the throttle bar vibrating, but I don't see how;
and I guess it could be the throttle cables vibrating I guess, but again,
what can I do about that?

What could be causing this cyclic RPM change?
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  #2  
Old May 5th 20, 08:15 PM posted to rec.autos.tech
[email protected]
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Posts: 539
Default Motor is wheezing, as if it's breathing - why?

Arlen Holder:

I had the same issue last year with the B&S engine on my self-propelled.

Not a 'wheezing' as I interpret it, but the up & down RPMs. Finally, it would run
only while I was bent over and pressing the gas prime bulb - made mowing the
lawn interesting, to say the least! Does yours run smoother if you hold in the
primer while it is running.

My local small engine shop cleaned a lot of dirt & gummed up grime out of the
carburetor and the fuel intake jets on my machine. Those fuel intakes are almost
as small as the period on your screen . They can gum up easy!

Have someone take a look at that aspect of it.
  #3  
Old May 5th 20, 08:42 PM posted to rec.autos.tech
Arlen Holder[_4_]
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Posts: 11
Default Motor is wheezing, as if it's breathing - why?

In response to what > wrote :

> I had the same issue last year with the B&S engine on my self-propelled.


Thanks for hazarding advice, as I know how risky that is on the Internet.

With the exception of this four stroke push lawnmower being a California
carb'd engine, they're all likely similar in many ways.

> Not a 'wheezing' as I interpret it, but the up & down RPMs. Finally, it would run
> only while I was bent over and pressing the gas prime bulb - made mowing the
> lawn interesting, to say the least! Does yours run smoother if you hold in the
> primer while it is running.


There is no primer that I know of. The only controls are the choke and the
throttle, where neither is much of a control because the choke only lasts a
handful of seconds (it slides back into place unless you physically block
it somehow) - and the throttle is a lever on the top of the push bar where
letting it go shuts off the engine (as a safety feature).

The throttle bar has been taped tightly for years.

> My local small engine shop cleaned a lot of dirt & gummed up grime out of the
> carburetor and the fuel intake jets on my machine. Those fuel intakes are almost
> as small as the period on your screen . They can gum up easy!
>
> Have someone take a look at that aspect of it.


I wouldn't even think of taking an engine in to a shop, but it might be
that the carb is gummed up. The engine starts on the first pull of the
cord, so it must be a 'slight' gumming of an orifice if it is.

I thought about _replacing_ the filter instead of just cleaning it, but it
didn't look bad (one side had grass clippings stuck to it which I had
banged off, but the inside edge was clean as brand new where it's likely a
year or two old).

Given it starts right up, it can't be too badly off the stoichiometric
ratio, but I do agree that the fuel jets are likely tiny. They're not
adjustable as far as I know though (California rules I think).

I hate to take apart the carb if I don't have to though.
That's why I asked.
--
Usenet is a wondrously rich public helpdesk to politely discuss solutions.
  #4  
Old May 6th 20, 12:17 AM posted to rec.autos.tech
[email protected]
external usenet poster
 
Posts: 539
Default Motor is wheezing, as if it's breathing - why?

Arlen:

No squishy rubber thing down on the side of the block?

But you have in place of it a choke lever. Always hated trying to start up them
'two-slider' deals, lol! Reminds me of Dad's old flip-handle windup horror from
the late '60s. He could storm n curse at that thing like you never! lol

Wind it up, flip the winder shut, jump back behind the machine, and flip the
choke and throttle levers at just the right time, might fire up n run for ten seconds,
"sunovabitch!" Bend over, flip open, wind. repeat. Nice way to spend a friday
evening or Saturday!

But yeah, run the make and model on line, I'm sure there's an owners or service
manuel for it out there. Sounds like it's perpetuallly on the verge of stalling for
lack of fuel, or clean air, but you probably already checked that filter.
  #5  
Old May 6th 20, 03:17 PM posted to rec.autos.tech
Steve W.[_6_]
external usenet poster
 
Posts: 1,161
Default Motor is wheezing, as if it's breathing - why?

Arlen Holder wrote:
> It's a Honda lawnmower I'm asking about, which is about 10 years old, but
> which runs fine most of the time.
>
> I replaced the plug, ran a tank of fresh gas, and cleaned the filter, and
> yet, it "wheezes" like it's breathing, normal rpm, and then slower rpm and
> then normal rpm and then slower rpm and then normal rpm and then slower
> rpm, etc, ad infinitum.
>
> The interval is only about a second or two at most for this
> stoichiometric:lean stoichiometric:lean stoichiometric:lean cadence to
> occur and the stoichiometric:leancycles are quite regular.
>
> The (California) carb on this thing is not adjustable (AFAIK), and the
> choke shuts off in seconds as it's merely a slider that glides back in
> place in a couple of seconds after initial activation.
>
> Even after a half hour of running, the stoichiometric:lean wheezing only
> gets slightly less pronounced, where the stoichiometric:lean wheezing I'm
> talking about is when there is no load (e.g., it's sitting level on a
> sidewalk). (Under load, it's harder to tell, but there's no "speed"
> adjustment given I have the throttle bar on the handle taped tight in the
> always-full-on position.)
>
> I'm thinking it's all in the carb - i.e., choke and/or throttle...
>
> So I guess it "could" be the throttle bar vibrating, but I don't see how;
> and I guess it could be the throttle cables vibrating I guess, but again,
> what can I do about that?
>
> What could be causing this cyclic RPM change?


Sounds like a blocked jet. On the typical non adjustable carb they are
set up to run lean and draw through both the idle circuit and the main
circuit to get enough fuel to run properly at full rpm. One jet starts
to gum up and you get rpm surge. Two choices for repair, pull the carb,
take it apart and clean it in a carb bath or ultrasonic cleaner. Or
replace it with one of the hundreds of replacements out there.

You could try adding some seafoam to the fuel and see if you can clear
it out that way but it really depends on just how plugged it is as to
whether that will work.
--
Steve W.
  #6  
Old May 6th 20, 06:10 PM posted to rec.autos.tech
Arlen Holder[_4_]
external usenet poster
 
Posts: 11
Default Motor is wheezing, as if it's breathing - why?

In response to what "Steve W." > wrote :

> You could try adding some seafoam to the fuel and see if you can clear
> it out that way but it really depends on just how plugged it is as to
> whether that will work.


Thanks Steve W for that helpful advice.

I think it is one of those non-adjustable jets which are clogged.
The engine runs, so I "can" put seafoam in, but I'm no fan of what I call
"miracles in a can".

The Seafoam is likely just a trademark for a lot of stuff, mostly likely a
formulation of soap for gas, aka polyetheramines, which are already in
gasoline - but let me look it up...
<https://seafoamsales.com/product/sea-foam-motor-treatment-oil-fuel-additive/>
<https://seafoamsales.com/sds/>

Hmmm... 10% to 30% alcohol wasn't expected.
The petroleum distillates and hydrocarbon-based solvents were expected.

Anyway, I've never been a fan of miracles in a can, and I know you
suggested it as a side note to the real problem, which is that the jets are
likely clogged.

For now, since it's running, I think I'll just use a few tanks of gas and
see if that cleans it out. I also might tie down the throttle cable a bit
more, and ensure the throttle and choke levers aren't vibrating.
--
Usenet is where purposefully helpful adults publicly help each other.

  #7  
Old May 6th 20, 06:10 PM posted to rec.autos.tech
Arlen Holder[_4_]
external usenet poster
 
Posts: 11
Default Motor is wheezing, as if it's breathing - why?

In response to what > wrote :

> No squishy rubber thing down on the side of the block?


Nope.
Anyway, I think the answer is one of the non-adjustable jets is clogged.

What I'll do, since the mower is running, is use it for a while.
Hopefully that will clean it out on its own.

Thanks for the helpful advice which I much appreciate.
--
Usenet works best when adults post with purposefully helpful intentions.
  #8  
Old May 6th 20, 07:34 PM posted to rec.autos.tech
Scott Dorsey
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Posts: 3,914
Default Motor is wheezing, as if it's breathing - why?

Arlen Holder > wrote:
>It's a Honda lawnmower I'm asking about, which is about 10 years old, but
>which runs fine most of the time.
>
>I replaced the plug, ran a tank of fresh gas, and cleaned the filter, and
>yet, it "wheezes" like it's breathing, normal rpm, and then slower rpm and
>then normal rpm and then slower rpm and then normal rpm and then slower
>rpm, etc, ad infinitum.


Your carb bowl is emptying at a rate faster than it is filling. It is likely
full of crap. Take it apart and clean it properly.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #9  
Old May 6th 20, 08:29 PM posted to rec.autos.tech
Steve W.[_6_]
external usenet poster
 
Posts: 1,161
Default Motor is wheezing, as if it's breathing - why?

Arlen Holder wrote:
> In response to what "Steve W." > wrote :
>
>> You could try adding some seafoam to the fuel and see if you can clear
>> it out that way but it really depends on just how plugged it is as to
>> whether that will work.

>
> Thanks Steve W for that helpful advice.
>
> I think it is one of those non-adjustable jets which are clogged.
> The engine runs, so I "can" put seafoam in, but I'm no fan of what I call
> "miracles in a can".
>
> The Seafoam is likely just a trademark for a lot of stuff, mostly likely a
> formulation of soap for gas, aka polyetheramines, which are already in
> gasoline - but let me look it up...
> <https://seafoamsales.com/product/sea-foam-motor-treatment-oil-fuel-additive/>
> <https://seafoamsales.com/sds/>
>
> Hmmm... 10% to 30% alcohol wasn't expected.
> The petroleum distillates and hydrocarbon-based solvents were expected.
>
> Anyway, I've never been a fan of miracles in a can, and I know you
> suggested it as a side note to the real problem, which is that the jets are
> likely clogged.
>
> For now, since it's running, I think I'll just use a few tanks of gas and
> see if that cleans it out. I also might tie down the throttle cable a bit
> more, and ensure the throttle and choke levers aren't vibrating.


Seafoam has been one of the few cans that I have had work in this
situation. Also works very well as a top cylinder cleaner for those
vehicles that get carbon build up on the pistons and rings.
The ingredients may be in gasoline, but not in the concentration
required to dissolve the deposits that formed from evaporation.

Now if you had a heated ultrasonic cleaner available, those do a really
good job on getting them clean.

--
Steve W.
  #10  
Old May 7th 20, 10:01 PM posted to rec.autos.tech
Arlen Holder[_4_]
external usenet poster
 
Posts: 11
Default Motor is wheezing, as if it's breathing - why?

In response to what "Steve W." > wrote :

> The ingredients may be in gasoline, but not in the concentration
> required to dissolve the deposits that formed from evaporation.


Hi Steve W,

I appreciate your advice, where I know how risky any advice is on Usenet.

Rest assured I understand what you're saying, which is that the
polyetheramines, and perhaps the alcohol and petroleum distillates in
something a marketing team calls "Seafoam" are _different_ than what's in
gasoline, even as they are diluted _in_ that very same gasoline.

Essentially, diluting that solution is said to turn a tank of gasoline into
a tank of "carb cleaner" (and perhaps cylinder wall cleaner too!).

I get that as I'm very familiar with polyetheramines being a "soap for
gas", which is why I buy only Tier 1 fuels like Costco gasoline.

The problem I have with solutions like "Techron" or "Seafoam", are that, in
the end, they're merely trademarks, which are, in and of themselves,
meaningless (except to a MARKETING organization).

They can put that trademark on _anything_ they want to put it on.
o Yet, I understand the point - which is my jets are likely gummed up.

I agree with that point so I don't disagree with the concept that _more_
soap for gas might be better than simply using the Tier 1 Costco fuels.

In the end, I agree with everyone who suggests that my "surging" idle is
likely due to a clogged jet inside the carb, which, as you noted, has
mechanical solutions - but which - understandably - are more work than
simply adding solvents into the fuel tank.
--
Adults gather on Usenet to politely learn via public technical discussion.
 




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