Remove Spark Arrestor From 4-Stroke INV Generator?

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gathermewool

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Most of the threads online pertaining to this topic are for off-road bikes and ATV's, with some other OPE sprinkled in. The consensus seems to be that it will provide more performance for two-strokes, if you rejet the carb (didn't see 4-strokes mentioned); also, that you should leave it on if there's a risk of starting a wild-fire.

I've got a WEN 2kW inverter generator with a clamped-on metal mesh screen. When I pull it off to clean it, there's a cone-shaped metal-mesh filter inside of this, also. I ran the generator without it and it definitely helped the 0-60 time, but I'm wondering if it's worth it.

Seriously, if it's run on a concrete slab with the nearest flammable object 5'+ away, does it matter? Will it cause a lean condition? Will it provide lower fuel consumption?

This thing is already very good on gas, considering it's usually never even close to half load (average) while it's actually needed for a power outage.
 
What do you mean when you say your generator has a 0-60 time?

And yes if you aren't running the generator near any dry combustible materials then I don't see why the spark arrestor is needed. However, if you remove it, and by some odd series of events your house burns down.. the insurance company might not be so happy about your decision.
 
Originally Posted By: Reddy45
What do you mean when you say your generator has a 0-60 time?

And yes if you aren't running the generator near any dry combustible materials then I don't see why the spark arrestor is needed. However, if you remove it, and by some odd series of events your house burns down.. the insurance company might not be so happy about your decision.


I was just joking about the 0-60 time.

I would observe an extended run time at night before I ever made this a permanent modification. One bit of carbon and I'd nix the whole thing.

Originally Posted By: dwendt44
The slight reduction in back pressure should improve
the 'gas mileage' a small amount. Does it alter the noise
level?


It's definitely louder, but not by much. I can't tell the difference in the house and I've got a couple of acres between me and the neighbors.
 
My goal for a generator would be quiet. I would be adding mufflers on top of mufflerz. Other than that, I would leave it. Those engines are designed to run efficiently in a narrow speed range. It is not like a car engine that might see an improvement at high RPM when removing an exhaust restriction.
 
Originally Posted By: eyeofthetiger
My goal for a generator would be quiet. I would be adding mufflers on top of mufflerz. Other than that, I would leave it. Those engines are designed to run efficiently in a narrow speed range. It is not like a car engine that might see an improvement at high RPM when removing an exhaust restriction.


It's an inverter generator, so exact speed is irrelevant. It actually has a low RPM switch for low-load operation, to save gas.

Again, the noise difference is minimal - it's not Honda inverter generator quiet, but close enough not to matter for where I run it in relation to where we will be while it runs.
 
As a general rule, anything that reduces pumping losses increases efficiency. Exhaust restrictions absolutely make the engine work harder.

Now, as to whether it's actually a big restriction or not is anybody's guess. We would need instrumented testing to determine how much difference the screen makes.

It's entirely possible the muffler has small openings inside that create the majority of the restriction and that pulling the screen will do nothing.

Now, before somebody chimes in and says "some backpressure is necessary" that's an old wives tale. It IS true that some engines with sufficient cam timing overlap do benefit from exhaust restriction at low RPM. But that is a factor of cam timing, and has nothing to do with backpressure being helpful.
 
My chainsaw and trimmers all have their screens removed. I also have removed from my sidebyside. I gotta say that i dont think that it makes a bit of difference..

My riding buddy has 4X the miles on his sidebyside and has the spark arrestor and never cleans his..runs fine.

He has a very similar trimmer to mine and he uses his alot more than me...he hasnt touched the screen. runs just fine.

I say leave it alone..doesnt help a thing.
 
Originally Posted By: krismoriah72
My chainsaw and trimmers all have their screens removed. I also have removed from my sidebyside. I gotta say that i dont think that it makes a bit of difference..

My riding buddy has 4X the miles on his sidebyside and has the spark arrestor and never cleans his..runs fine.

He has a very similar trimmer to mine and he uses his alot more than me...he hasnt touched the screen. runs just fine.

I say leave it alone..doesnt help a thing.


I will dissagree with you...did a muffler modification on my EPA chainsaw and it runs way better...
 
Good, I'm glad we have a consensus.
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First thing I did with my Yamaha EF2000is was pull the screen from the exhaust. Over 1400 hours on it now and it runs better than new. Fuel consumption is exceptional! Oil consumption was a problem when new but once it had over 900 hours on it, oil consumption dropped significantly.

I take the spark arresters out of pretty much everything. I even drilled out the catalytic converter from my Echo Chainsaw.
 
Originally Posted By: Cujet
As a general rule, anything that reduces pumping losses increases efficiency. Exhaust restrictions absolutely make the engine work harder.

Now, as to whether it's actually a big restriction or not is anybody's guess. We would need instrumented testing to determine how much difference the screen makes.

It's entirely possible the muffler has small openings inside that create the majority of the restriction and that pulling the screen will do nothing.

Now, before somebody chimes in and says "some backpressure is necessary" that's an old wives tale. It IS true that some engines with sufficient cam timing overlap do benefit from exhaust restriction at low RPM. But that is a factor of cam timing, and has nothing to do with backpressure being helpful.


Right on. Backpressure is dumb. Exhaust tuning is all about maintaining exhaust velocity, and that changes with port/tubing size and shape, temperature change, and timing of exhaust pulses for scavenging.
 
How can you tell if you have a cat? The emissions sticker on the generator shows low emissions and I believe it is CARB and EPA-3 compliant, but I haven't been able to find out online whether that means there's a cat for the exhaust or not.

This thing does well by itself and its exhaust seems very clean (no smoke and low odor), so I don't intend to do anything to change that. For OPE, I can see why this would be beneficial.

//

I just got an older Cub Cadet CC550 mower for free and noticed that its muffler does not have anything installed on the tip. Online research leads me to believe that it did not come with a spark arrestor, but one can be purchased (for way too much money.)

//

I'll be getting a weed wacker for free some time soon. It doesn't run and has been sitting for a while, so it'll likely need to be pulled apart anyway. I'll see if it has a spark arrestor. How can you tell if it has a cat, besides looking it up online?
 
Well , we lost power around 8 hrs ago. Even though it's wet outside I left the spark arrestor on. I'll decide later if I want to remove it.

On a side note, it's nice to know my fridge only draws a few hundred watts (estimated - indicated was less, though likely too slow to show max initial current draw.) it evened out at ~130W, while also charging lights and batteries. This is low enough to run the generator in eco mode.
 
Originally Posted By: boraticus
First thing I did with my Yamaha EF2000is was pull the screen from the exhaust. Over 1400 hours on it now and it runs better than new. Fuel consumption is exceptional! Oil consumption was a problem when new but once it had over 900 hours on it, oil consumption dropped significantly.

I take the spark arresters out of pretty much everything. I even drilled out the catalytic converter from my Echo Chainsaw.
How long have they been putting catcons in chainsaws?
 
I bought the saw 11 years ago, so at least that long. Not sure if all brands did/do put catcons in their saws, but the Echo CS346 had one.
 
Originally Posted By: boraticus

I bought the saw 11 years ago, so at least that long. Not sure if all brands did/do put catcons in their saws, but the Echo CS346 had one.
Interesting, I had no idea they had them, especially 11 years ago! I'm sure, due to ever increasing emissions rules, more OPE's have them now.
 
Originally Posted By: xxch4osxx
Originally Posted By: boraticus

I bought the saw 11 years ago, so at least that long. Not sure if all brands did/do put catcons in their saws, but the Echo CS346 had one.
Interesting, I had no idea they had them, especially 11 years ago! I'm sure, due to ever increasing emissions rules, more OPE's have them now.


Yea, this is all new to me, too. I would not have thought that any small engine had a cat. I assumed their cleaner-smelling exhaust was simply related to tuning, because many older OPE seems to stink like any other OPE I can remember...maybe everyone is boring out cats!
 
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