GENRATOR High altitude Jet

[Colo_Native]

I have my Champion generator and did the break in, now I put the high altitude(3500'or higher) and I must say it was a PITA how many people leave it in or don't use it because it is a PITA. I would say about half the time I would be at altitude so Is it really needed?

[MEXICOWANDERER]

Maybe rearranging your hairstyle will minimize your issues.

[SidecarFlip]

Some posters on this site have flat heads as well

[pnichols]

MEXICOWANDERER wrote:
Flathead prime movers. Old Onans.I have had the heads shaved .080" which really improved high altitude power.

Hmmm ... improves low altitude power, too.

At least it did on my good-old flat head MGA roadster .... until I wound up floating the valves from too much exceeding of the RPM redline. :B

[MEXICOWANDERER]

Flathead prime movers. Old Onans.I have had the heads shaved .080" which really improved high altitude power. Cannot do to overhead valve motors.

[MEXICOWANDERER]

Yes and from a thousand miles distance this is what China will look like


Keeping the planet clean Clean CLEAN!



Don't believe it? Just look out your window (in the Western Hemisphere)

[Chum_lee]

KJINTF wrote:
Might be worth your time to read through this thread

Sounds like CARB and the EPA might have a hand in some of the lean running small engines.

Changed my #85 Honda HSS928AATD main jet to an #88 - for me an excellent change no more bogging down in thick heavy wet slush snow

http://www.snowblowerforum.com/forum/honda-snowblowers/128193-re-jetting.html

Yep! CARB and the EPA would like nothing more than to see ECU's, fuel injection, catalytic converters, etc., in short, as close to zero emissions as possible from every future internal combustion engine made. (just like cars) Cost is the prohibitive factor. Imagine the day when the emission control equipment on your leaf blower costs more than the leaf blower itself. It's coming! Elon Musk is waiting.

Chum lee

[Huntindog]

SidecarFlip wrote:

Chum lee wrote:
Running your generator at higher altitudes with the sea level jetting will cause it to run rich. It may smoke a little, maybe not. It will use more fuel than necessary and it may foul the spark plug and/or dilute the engine oil with fuel. Running it at sea level with the high altitude jet will cause it to run lean. You may experience loss of power, hard starting/rough running, or excessive engine temps.

Time will tell how it effects longevity. Your choice.

Chum lee

I always thought it was just the opposite. Higher the altitude, thinner the air, fatter the jet orfice to compensate foe the thinner air.

Ummmm. You always thought wrong.
Thinner air means less oxygen. You need to reduce the gas flow (smaller orfice/jet) to keep the air/fuel ratio the same as it is at sea level.

[KJINTF]

Might be worth your time to read through this thread

Sounds like CARB and the EPA might have a hand in some of the lean running small engines.

Changed my #85 Honda HSS928AATD main jet to an #88 - for me an excellent change no more bogging down in thick heavy wet slush snow

http://www.snowblowerforum.com/forum/honda-snowblowers/128193-re-jetting.html

[pnichols]

You have to be very careful if permanently rejetting an RV generator for high altitude use thinking that you're now all set for more efficieint and smooth running at high altitudes if that's where you might be camping and also still OK to run it sometimes at low altitudes if that's where you might be camping.

Rejetting for high altitudes means that the engine will now run lean (not enough gasoline to match the amount of air) at low altitudes. Running lean makes the engine run hotter - which is very hard on it.

I once rejetted an engine for high altitude operation and then did not change the jets back to stock when moving back to low altitude. This lean and hotter running at low altitude day after day burned holes in the engine's valves.

That's why the Onan built-in generators with a knob adjustment for altitude are so nice - it's ultra quick and convenient to use them at their highest efficiency at all altitudes without risking harm to their engines if you remember to set this knob to LOW ALTITUDE whenever you're at low altitude. I just leave our RV's Onan generator set to sea level and get by with it's running a bit rich (too much gasoline to match the amount of air) at high altitudes ... but we don't usually camp for long time periods at high altitude, either ... if and when we do, I'll tweak the Onan's altitude knob to whatever altitude we're squatting at.

[MDKMDK]

Chum lee wrote:

MDKMDK wrote:
I thought many Onan built ins did have altitude adjustment levers or screws on the carburetor models? Or, are fuel injected, if not?

They do. My Onan 4000 (gas) genny has an altitude (mixture) adjustment on the bottom of the carburetor. You have to take the exterior cover panel off to see it.

Chum lee

My Onan 2.8Kw also had an altitude lever to adjust the mix. I think it had a 10,000ft max, but I never needed it as we never ran it that far up in the hills.
I'm not sure about the QD models.

[Sandia_Man]

We have had our Champion 3100 remote start inverter genny for 3 years and had no issues running it at 5600' elevation here at home with the stock carb jet. Read the manual and it declared we needed a high altitude jet as you indicated above, called Champion and they readily sent one out. Installed it and found that after running it with the new jet I could tell no difference in performance or power production.

We predominately camp at high elevations so I just left it in there for the time being, we ran it with the stock jet for nearly a year, even above 8K' elevation and it performed well. I wouldn't be too worried running the stock jet for occasional use at higher elevations if that scenario works better for you. I didn't find replacing carb jet overly taxing as I set it on a work table making it easy to maneuver, after the first time the process is not too bad.

[GWolfe]

I've ran my Champion 3100 watt at 10,100' where we camp at Taylor Park CO. with no issues. Three years I've done this, we camp for 10 days and I use it mainly for battery charging but have ran the coffee maker and microwave without any issue. I've never tried the AC up there though.

All with the factory jet BTW.

[Chum_lee]

MDKMDK wrote:
I thought many Onan built ins did have altitude adjustment levers or screws on the carburetor models? Or, are fuel injected, if not?

They do. My Onan 4000 (gas) genny has an altitude (mixture) adjustment on the bottom of the carburetor. You have to take the exterior cover panel off to see it.

Chum lee

[SidecarFlip]

MEXICOWANDERER wrote:
Advancing the timing did a lot more than re-jetting for me.

How do you 'adjust' the timing on a solid state trigger actuated ignition system?