Carb jetting for high elevation

[BigJohn]

I have searched the web quiet a bit and haven't found the info I am looking for....

I have a new piece of equipment that is powered by the B&S 13.5hp 420cc engine. The thing is.... my property is at 7,800 feet elevation. I am pretty certain B&S jets these engines for sea-level or may a little higher out of the factory, but certainly not 8,000 feet.

At which elevation level does a company like B&S recommend the high elevation jet?

Does anyone have any experience with this?


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[c502cid]

I bought a tiller last year. In the instructions it said you needed a different jet for high altitude. I emailed them and they sent it for free. It wasn't a Briggs motor though. My guess is to contact the manufacturer of the equipment or Briggs and ask. You won't be the first to ask the question. Or go to a local small equipment dealer that is at your altitude.

 

[MRC01]

I don't know what B&S recommends, but with most engines as a general rule it starts to make a difference above 5,000. So you should definitely ask, as @c502cid suggests.

 

[BigJohn]

Thanks.. I will give them a ring.

 

[wag123]

It might not make much of a difference, and it might run better. These newer low emission engines are jetted so lean that a little altitude might bring it into a better running A/F ratio range. Run it before you mess with it. If it breaks-up at wide open throttle when warm then you will need to re-jet it.

 

[ripcord]

My folks are at 5500 feet and I never noticed their mowers and tillers running excessively rich with stock jets. My 64 Fairlane on the otherhand was definitely on the rich side when coming from sea level.

 

[BigJohn]

It might not make much of a difference, and it might run better. These newer low emission engines are jetted so lean that a little altitude might bring it into a better running A/F ratio range. Run it before you mess with it. If it breaks-up at wide open throttle when warm then you will need to re-jet it.

I am taking the equipment up to the property this afternoon and will fire it up and see how she does. I will report back......


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