Good or Bad ?, Running Generator on Eco Throttle

Submitted: Monday, Sep 17, 2012 at 20:16
ThreadID: 98079 Views:12710 Replies:7 FollowUps:8
This Thread has been Archived
I have been lead to believe that the side affect of running a generator on eco throttle is that the engine cylinder will glaze and start burning oil and creating carbon that fouls the valves. I am told this a problem with both Honda and Yamaha.

A couple of sources have suggested to me its best to run with eco throttle off. Apparently works great in other countries with better quality fuel I imagine most people would run their generators on eco throttle to reduce noise and save fuel.

So do you use the eco throttle feature and run your generator under alight load and have you experienced any issues like oil burning or failures.

Thanks Peter
Back Expand Un-Read 0 Moderator

Reply By: Ross M - Monday, Sep 17, 2012 at 22:07

Monday, Sep 17, 2012 at 22:07
I don't think the fuel quality has anything to do with ECO setting. Most fuel here from reputable companies is = to other countries. Although Shell fuel isn't as good as BP or Caltex or Mobil. Motorcycles don't like Shell and often dealers will tell you not to use Shell petrol.

After the generator is run in, it should be able to use the specified oil or better without glazing. I use Mobil 1 synthetic after it is run in.

Eco throttle matches the engine energy output setting to the electrical energy required to run the appliance. Therefore, the actual Eco speed setting depends on the load applied. It is not just one low speed necessarily. If you fully load it on the Eco setting it will run full output as if the Eco was OFF.
Eco on no load will make it idle. Some load will increase the revs and also the energy output.
It is probably best to run the generator with various items connected at the same time and take advantage of the economy the Eco setting provides without it hammering away at unnecessary high revs.

By running with it Eco OFF, it is running at full governed revs and the full load will be making it work the hardest. Also, higher revs will obviously lessen the life.
The glazing is caused by prolonged light load at lower revs. Unless you continually put it in that situation glazing shouldn't occur. Probably some people unwittingly do create the situation for glazing. Can happen to any engine.
Occasionally give it near full load with Eco OFF to keep an operating balance of use.

Make sure loads and therefore speeds are varied with different appliances/load and Eco will manage the speed/energy required.
If the appliance is something which is starting and stopping all the time then Eco OFF is more suitable as the energy is there available and it doesn't have to catch up everytime the load switches on,eg electric drill driving in screws.


Ross M
AnswerID: 495127

Reply By: Dennis Ellery - Monday, Sep 17, 2012 at 22:24

Monday, Sep 17, 2012 at 22:24
Sounds like a lot of waffle to me.
I have a Yamaha EF2400is – it has no economy idle off switch – it is always on.

As for different fuels - in WA the fuel comes from the local BP refinery - whether it be Ampol, Shell or what ever. Some of the independant operators used to import from Singapore but I don't think that goes on anymore as they weren't up to Australian standards
AnswerID: 495130

Follow Up By: Ross M - Monday, Sep 17, 2012 at 23:12

Monday, Sep 17, 2012 at 23:12
G'day Dennis.
Glad you liked the explanation.
A builder friend has a Yamaha EF2400. Unfortunately it too has to run all the time at full speed/ noisey and after a reasonable amount of use, burns oil cos of the continual high revs.
I changed the oil in it to a synthetic and it made it quieter and also minimized the rate of oil consumption. I was surprised how much oil it used.
Rings must be prematurely worn out.
FollowupID: 770771

Follow Up By: Member - kwk56pt - Monday, Sep 17, 2012 at 23:44

Monday, Sep 17, 2012 at 23:44
Thanks Ross M for a sensible reply which outlines a good strategy for operating these generators. I wonder how many run for hours just powering a fridge or just using the dc output to charge a battery. Of course a battery charger is the go but some people think the Dc output is the go for recharging batteries. Sounds like you have had good service from your generator.
Cheers Peter
FollowupID: 770774

Follow Up By: Bob Y. - Qld - Tuesday, Sep 18, 2012 at 09:23

Tuesday, Sep 18, 2012 at 09:23

" for hours just powering a fridge........" Perhaps this is where the problem lies. I doubt if Honda designed these little units to do just that. Their planned use would have been intermittent use, such as emergency use, or lights for a couple of hours, or light, compact use for tradies etc. Am sure they were never designed to run for 10-12 hours per day, almost every day.

One could question the servicing regime of these ones that are burning/using lots of oil. Do they get serviced regularly? And do they get these services to match the hours being done? When they do start to use oil, is the oil level checked every time it's started, or only topped up when the low oil cut-out stops the engine?

We had a honda powered genny many years ago, that used to carbon up regularly. Spoke to a learned bloke about this, and he suggested using single grade oil. Swapped from a multi-grade to SAE 30, and no more carbon problems.

Haven't had much to do with the EU10 & EU20, but reckon they are great little units.Ross makes a good point about the way they are loaded up, and perhaps owners need to run a bit more than the laptop, doing their blog of course, and power up a light, battery charger or similar, to keep some load on the unit.

Wish i had one,


Seen it all, Done it all.
Can't remember most of it.

Lifetime Member
My Profile  My Blog  My Position  Send Message

FollowupID: 770785

Follow Up By: Dennis Ellery - Tuesday, Sep 18, 2012 at 09:29

Tuesday, Sep 18, 2012 at 09:29
As old olcoolone says – its an urban myth
Eco throttle is slow idle and non-eco is fast idle and the difference between the two on glazing effect would be negligible.
If a motor was prone to glazing – idling a new motor for long periods can contribute to it
If this was a problem for quality manufacturers like Yamaha and Honda they would have a run-in procedure detailed in their operating manuals.
A lot of mechanical plant failures are due to inappropriate use by operators.
A number of years ago I had to investigate the premature failure of a Briggs and Straton genset being used on a building site. I found out that the operator had been topping it up with dirty sump oil being used on formwork bolts.
FollowupID: 770786

Follow Up By: Bob Y. - Qld - Tuesday, Sep 18, 2012 at 09:39

Tuesday, Sep 18, 2012 at 09:39
Operator error/misuse. Ha ha. Never mentioned until they're found out, Dennis.

Knew a bloke bought one of those Briggs & Stratton powered Dunlite gennies, with horizontal cylinder, and about 1000 watts. Most upset when it melted the power outlet, and shorted the unit out. Turns out he was running a 1500 watt bar heater off it!!!!!!!!!


Seen it all, Done it all.
Can't remember most of it.

Lifetime Member
My Profile  My Blog  My Position  Send Message

FollowupID: 770788

Reply By: Kris and Kev - Tuesday, Sep 18, 2012 at 08:13

Tuesday, Sep 18, 2012 at 08:13
I think one point also should be mentioned.

In eco throttle the noise level, depending on what you are running off the generator, is generally lower. That is better for fellow campers!

AnswerID: 495136

Reply By: olcoolone - Tuesday, Sep 18, 2012 at 08:23

Tuesday, Sep 18, 2012 at 08:23
We have 4 EU20I generators in our service vehicles and they run 5-6 days a week on and off on eco throttle and has never missed a beat....... and they don't get serviced as often as the should..... we have never had a problem with them and they have never let us down.

Our newest one is now 3 years old.

Think your original question should go down as a urban myth like so many other misconceptions out there..... did you ask they ones who told you if they have ever had this problem and if the use a Honda or Yamaha generator..... maybe they sell another brand?

If they did have an issue don't you think Honda and Yamaha would of addressed it by now or remove the eco function.
AnswerID: 495137

Follow Up By: Member - kwk56pt - Tuesday, Sep 18, 2012 at 10:22

Tuesday, Sep 18, 2012 at 10:22
Thanks for all the replies. There doesn't appear to be any unhappy owners with units burning oil. i bought a second hand Honda so I don't know its history and although it started straight away and did not smoke the oil disappeared from the sump down to the oil alert in about 25 hours.

I enquired at two dealers and one said no honda should use oil but went on to tell me the problem was common to both Yamaha and Honda due to light loads and suggested it spent some time with the eco throttle off or under a decent load. The other dealer sold yamaha and told the same story when I enquired about oil burning.

So what counts is the majority if not all the owners are happy and the issue is not wide spread. Of course it probably depends what loads they are given and the variety of loads.

But I agree its looking like a urban myth judging by the replies.

Thanks again
FollowupID: 770794

Follow Up By: Ross M - Tuesday, Sep 18, 2012 at 14:40

Tuesday, Sep 18, 2012 at 14:40
The term "Urban myths" as stated by Dennis may not apply if outback where there is no urban. Lots of people believe things which is told to them by their mates, things which aren't necessarily true. I call it being MATED, and if you believe it you usually have the same set of problems they have.

The charging of batteries is best done by a multi stage 240v charger rather than the dc output of the generator.

The oil disappearing from the sump may be from glazing but could also be from incorrect oil or oil which is diluted with fuel blowby and contamination residue which has depleted the ability of the oil, which will render it unsuitable for the purpose.
FollowupID: 770818

Follow Up By: olcoolone - Wednesday, Sep 19, 2012 at 08:00

Wednesday, Sep 19, 2012 at 08:00
Honda recommends changing the oil every 20 hours...

Ross there is no confusing what "urban myth" means to most but the is a big misunderstanding what "mated" means.....

Urban myth....
a story, esp one with a shocking or amusing ending, related as having actually happened, usu. to someone vaguely connected with the teller"

-the sexual partner of an animal
-a marriage partner
-(informal (mainly British & Australian & New Zealand) a friend, usually of the same sex: often used between males in direct address
-in combination an associate, colleague, fellow sharer, etc ? a classmate, a flatmate
-one of a pair of matching items
-short for first mate
-any officer below the master on a commercial ship
-a warrant officer's assistant on a ship
-(in some trades) an assistant ? a plumber's mate
-(archaic) a suitable associate
-See mate rates

-to pair (a male and female animal) or (of animals) to pair for reproduction
-to marry or join in marriage
-try to join as a pair; match"

.....I'll stick to "urban myth"
FollowupID: 770890

Reply By: Keith Q - Tuesday, Sep 18, 2012 at 10:32

Tuesday, Sep 18, 2012 at 10:32
Hello Peter
Here is my five bob's worth. Cylinder glazing leading to poor oil control used to be quite common in engines and I'm sure it still happens when engines are run at light loads for long periods. My experience is with large engines, but I'm sure it can happen to smaller engines too. I saw it many times with engines fitted to cranes, where they were sized for very heavy loads, but only lifted heavy loads once in a blue moon. The rest of the time they idled doing nothing at all. The other interesting point is that only the very occasional engine glazed. I also saw it with generator sets with similar load requirements. The problem is that once an engine glazes, often the only thing that will fix it is to strip it down and lightly hone the cylinders. Very expensive!
The trick is to give the engine some moderate exercise from time to time before the problem develops. I am very gentle with my diesel ute and consciously drive it hard up a long hill from time to time to loosen up the piston rings. Then I go back to trundling around!
So my suggestion, if you are concerned about glazing, is to connect your generator to a decent load from time to time. I dont know how big your generator is, but perhaps a couple of electric irons might do the trick, and the thermostats in the irons will vary the load a bit which will do your generator the world of good. Just make sure you dont overload it.
And if you use the time to do the household ironing, you will no doubt be a very popular guy around the house at the same time!
AnswerID: 495141

Reply By: pop2jocem - Tuesday, Sep 18, 2012 at 11:25

Tuesday, Sep 18, 2012 at 11:25
I am pretty sure that the cylinder bore glazing is caused a lot more by running the generators or any engine petrol or diesel on light or no load for extended periods of time. Turning the eco throttle setting off only speeds up the engine and does not increase the load.
The piston ring design is such that the combustion pressure forces the rings against the bore to assist with sealing. When the engine is not under load this pressure is very much reduced and so the rings polish the cylinder surface.
Hope this helps a bit.

AnswerID: 495143

Reply By: TerraFirma - Tuesday, Sep 18, 2012 at 14:46

Tuesday, Sep 18, 2012 at 14:46
The most common sense approach and one I use is to mix both on and off. Certainly from a maintenance standpoint when I start a gennie I haven't used for a while I turn Eco off after it has warmed up. The only issue I have ever had is stale fuel after inactivity and this is more me being slack.
AnswerID: 495163

Sponsored Links