# Honda EU10i excess fuel consumption



## Guy Cashmore (Mar 5, 2020)

Greetings.

So I have a 2019 Honda EU10i generator that I bought new last year, official UK model bought from an authorised dealer.

It has only done about 20 hours running, but from day one I noticed it was heavy on fuel compared to every other similar sized generator I have owned before.

So today I took it to a mates MOT station with a selection of test loads, we ran it connected to his exhaust gas analyzer to check if it was running rich or whatever, we got some surprising results.

At no load, minimum speed it was producing about 2% CO, pretty much perfect for a non-cat engine. 

At 100W load this increased to about 4%, at 400W load 6% and at 800W an absolutely filthy and actually quite dangerous 8% CO in the exhaust. We reckon this explains the excess fuel consumption, the question is why?

Looking in the parts book, the main jet has 3 options, .58, .55 and .52, mine has the richest option fitted from factory, the .58. What I can't find out is why these options exist and why mine has the richest and in my opinion wrong jet fitted?

Any ideas?

Guy


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## drmerdp (Apr 10, 2018)

The other jets exist for high elevations. Thinner air requires less fuel. That being said Honda equipment Generally adhere to very strict positions controls and are jetted very lean. 

Although an exhaust gas analyzer is a cool tool to have it isn’t very useful in this application. A wideband Air fuel ratio meter would be the tool needed to identify And quantify a rich condition.

The simple way of seeing what’s going on is to identify How many hours on a tank of fuel you getting at a specific load.

Brand new engines have Greater amounts internal friction that reduce as they break in. Maybe it’s too soon to tell if your machine is using an abnormal amount of fuel.

Does it stumble under no load, or have a hard time revving to accommodate surges of load? I have an older eu1000 but one deceiving thing is it has a very small gas tank.


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## Guy Cashmore (Mar 5, 2020)

A wideband air/fuel ratio meter still only measures the oxygen content of the exhaust gas (like a lambda sensor), but has some additional processing to give a simple output, unless you were thinking of a different tool? 

The analyzer we are using can give is an oxygen number too, although it's almost zero with such a rich mixture.


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## drmerdp (Apr 10, 2018)

I just wouldn’t use CO as a benchmark this isn’t a boiler or furnace, where a super lean mixture is proper. To lean on gas and your destroying your engine. 

You can absolutely use Lambda. Lambda and a wideband are two means to the same end. Both measure oxygen in the exhaust stream compared to a free air reference valve. 

Wideband reading for stoichiometric on gasoline is 14.7:1 
Lambda is .87

It won’t be dead on but should be close... erring on the side of rich.


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