stinkbait
Addicted to ArboristSite
It's amazing how low the compression is on the engines. Here is part of service manual that I have that list the compression numbers for the AH engines.
Interesting Tecumseh Engine Info
- Thread starter stinkbait
- Start date
Help Support Arborist Forum:
nmurph
ArboristSite.com Sponsor
that's good to know. i have several of those on different models that i had written off bc of such numbers......i guess i will have to revisit getting them going.
tried to rep, but it says i have to spread it around a little......
tried to rep, but it says i have to spread it around a little......
stinkbait
Addicted to ArboristSite
It also says that spark plug gaps should be between .030-.035, depending on the model.
That would explain why they don't have much power.
Nice info Stink.
Thanks Lee
Nice info Stink.
Thanks Lee
tomdcoker
Addicted to ArboristSite
I have an Echo 60 S and got a service manual for it recently.
The compression ratio is listed as 7 to 1. According to my math this would be 105 # compression max. Atmosphereic pressure 15# times 7=105.
Correct me if I am wrong. Tom
The compression ratio is listed as 7 to 1. According to my math this would be 105 # compression max. Atmosphereic pressure 15# times 7=105.
Correct me if I am wrong. Tom
lawnmowertech37
Addicted to ArboristSite
let me know what parts you need since i handle tecumseh parts also
I noticed how low my strunk will idle at, like 300rpm! most likely because of the super low compression and the porting arangment/port timing.
CSW
CSW
my dad has one of these motors in a snowblower. at first i thought ill never get this thing running with that low of compression, much to my suprise it fired on the second pull with some fresh gas!!
guess u cant use the rope test with these motors
guess u cant use the rope test with these motors
Thanks for posting that Mitchell. It don't surprise me any at all.
Mr. Bow Saw
Addicted to ArboristSite
It's amazing how low the compression is on the engines. Here is part of service manual that I have that list the compression numbers for the AH engines.
Thanks for posting this.
I have checked one of my AH81 engines and it had 125 PSI
and I was thinking it was not that great.
MostShady1
Addicted to ArboristSite
I'm glad to hear that I'm not the only one surprised by this. I am working on an old Sears D44. Urbicide hooked me up with some info on this model, stating that the engine was optimum at 90 psi. My first cold comp test yielded 130 psi. I don't know whether to be happy or worried . . .
little possum
Crash and Burn
Thanks for the info. Now I want to go check the Sears saws out and see what they read on the gauge
Jake
ArboristSite Lurker
At cranking speed! Most all newer 4 stroke engines have easy start compression release built into the cam, it bumps the exhaust valve at low rpm's (cranking) once the engine fires and rpm's increase the lever flips to the side. This is why it important to keep the valves adjusted otherwise they can be hard to start and/or kick back and break starter ropes and/or prawls.
MostShady1
Addicted to ArboristSite
Maybe it's just me, but i don't think the OP referred to 4 strokes. Thanks for this info, anyway.
mtfallsmikey
Addicted to ArboristSite
For those who could not rep Stinky...I got him for 'ya.
stinkbait
Addicted to ArboristSite
Yes, I was only referring to the AH 2-stroke models.
Those numbers are fairly typical for these low-revving utility engines, both 2 and 4 cycle. The 4 cycle sidevalve engines are like 5:1 compression ratio. These engines were destined for non-handheld machines, snowblowers and the like, where power density was less important than longevity and tolerance of ugly operating conditions. Makes them hard to kill.
J
J
stinkbait
Addicted to ArboristSite
If anyone wants to read more about the AH engines, just pm me your email and I will send you a pdf.
Nitroman
Addicted to ArboristSite
AH Engines
Hit me! I love reading about the oldies.
nitromahn AT yahoo DOT com
Thanks.
Hit me! I love reading about the oldies.
nitromahn AT yahoo DOT com
Thanks.
