• We should now be fully online following an overnight outage. Apologies for any inconvenience, we do not expect there to be any further issues.

Getting better performance out of my self propelled lawn mower

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

alfa147x

Lifer
Jul 14, 2005
29,307
106
106
Originally posted by: angry hampster
Originally posted by: alfa147x
Originally posted by: angry hampster
Keep us updated with pictures. Please give the mower a new paint job as well. :D

HELL YEAH! I just dont want to spend out the wazzooo

and btw i rather spend money on performance then looks

It's a lawn mower. I'm not really sure what you're expecting. :laugh:

money = 10c ;)
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Keep the bore the same. What you need is more air/fuel in and out.

Bigger carb, cooler plug, no muffler and you should be good to go.
 

alfa147x

Lifer
Jul 14, 2005
29,307
106
106
Originally posted by: spidey07
Keep the bore the same. What you need is more air/fuel in and out.

Bigger carb, cooler plug, no muffler and you should be good to go.

im pulling it apart tomorrow to see what im working with, why a cooler plug? bigger carb = more air\fuel? what about back pressure from the muffler? also can some one tell me why i need back pressure


thanks!
 

spidey07

No Lifer
Aug 4, 2000
65,469
5
76
Cooler plug because you'll have more combustion (more air/fuel). Bigger carb = bigger throttle body = more air/fuel. What I'm gathering is a single cylinder motor.

I'm by no means an expert on this stuff, but on simple motors like this backpressure isn't your concern...the motor is a big pump.
 

angry hampster

Diamond Member
Dec 15, 2007
4,232
0
0
www.lexaphoto.com
Originally posted by: alfa147x


im pulling it apart tomorrow to see what im working with, why a cooler plug? bigger carb = more air\fuel? what about back pressure from the muffler? also can some one tell me why i need back pressure


thanks!

The whole backpressure thing is largely a myth and does not affect a naturally aspirated engine at all. (In most circumstances) Just yank the muffler off and ride the sucker down the street. Yeah, I know it's a walk-behind mower. Just squat down on top of it, or ride on a dolly/skateboard/office chair behind it. :D
 

Colt45

Lifer
Apr 18, 2001
19,720
1
0
small 4-strokes are hopeless... find a beat down snowmobile with a 2cyl 2 stroke for $25 or something.
 

Black88GTA

Diamond Member
Sep 9, 2003
3,430
0
0
Originally posted by: spidey07
Cooler plug because you'll have more combustion (more air/fuel). Bigger carb = bigger throttle body = more air/fuel. What I'm gathering is a single cylinder motor.

I'm by no means an expert on this stuff, but on simple motors like this backpressure isn't your concern...the motor is a big pump.

Originally posted by: angry hampster

The whole backpressure thing is largely a myth and does not affect a naturally aspirated engine at all. (In most circumstances) Just yank the muffler off and ride the sucker down the street. Yeah, I know it's a walk-behind mower. Just squat down on top of it, or ride on a dolly/skateboard/office chair behind it. :D


Just a small correction...2-stroke motors won't run right without the proper exhaust pipe. Changing the characteristics of the pipe (shortening / lengthening it, or removing it completely) will alter the effective powerband of the engine, and will probably give you lots more noise, and lots less power (an un-muffled 2 stroke sounds like absolute shit, btw)

4 stroke motors are not as dependent on exhaust characteristics though...I'm assuming your mower is a 4 stroke (most are) but prepare for it to be obnoxiously loud if you take the muffler off. That little box does a lot more to reduce noise from that small engine than you might think. :)
 

alfa147x

Lifer
Jul 14, 2005
29,307
106
106
Originally posted by: Black88GTA
Originally posted by: spidey07
Cooler plug because you'll have more combustion (more air/fuel). Bigger carb = bigger throttle body = more air/fuel. What I'm gathering is a single cylinder motor.

I'm by no means an expert on this stuff, but on simple motors like this backpressure isn't your concern...the motor is a big pump.

Originally posted by: angry hampster

The whole backpressure thing is largely a myth and does not affect a naturally aspirated engine at all. (In most circumstances) Just yank the muffler off and ride the sucker down the street. Yeah, I know it's a walk-behind mower. Just squat down on top of it, or ride on a dolly/skateboard/office chair behind it. :D


Just a small correction...2-stroke motors won't run right without the proper exhaust pipe. Changing the characteristics of the pipe (shortening / lengthening it, or removing it completely) will alter the effective powerband of the engine, and will probably give you lots more noise, and lots less power (an un-muffled 2 stroke sounds like absolute shit, btw)

4 stroke motors are not as dependent on exhaust characteristics though...I'm assuming your mower is a 4 stroke (most are) but prepare for it to be obnoxiously loud if you take the muffler off. That little box does a lot more to reduce noise from that small engine than you might think. :)

Im planning for a surprise when i take the exhaust off, btw its a 4 stroke
 

zixxer

Diamond Member
Jul 6, 2001
7,326
0
0
Originally posted by: alfa147x
Originally posted by: angry hampster
Just pull off the muffler and open up their air intake element to make it more free flowing. No sense in dumping $$$ into a mower. Your neighbors will hate you btw. :laugh:

is it really that loud? they wont kill me if i try it out, one is a red neck the other is rebuilding a mustang thats loud as fuck w\o its exhaust

also would this harm the engine at all?

Buy a case of beer and invite them over. I bet you'll have a badass mower in no time...
 

alfa147x

Lifer
Jul 14, 2005
29,307
106
106
Originally posted by: zixxer
Originally posted by: alfa147x
Originally posted by: angry hampster
Just pull off the muffler and open up their air intake element to make it more free flowing. No sense in dumping $$$ into a mower. Your neighbors will hate you btw. :laugh:

is it really that loud? they wont kill me if i try it out, one is a red neck the other is rebuilding a mustang thats loud as fuck w\o its exhaust

also would this harm the engine at all?

Buy a case of beer and invite them over. I bet you'll have a badass mower in no time...

im 18...