honda em500 generator

spiff

spiff

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Hi all,

so my GF's retired pensioner father dug out this old honda em500 generator (see pic) the other day and asked if I can get it going.

I removed the old vrot filter, checked fuel lines etc. I cleaned the carb blowing out all the jets with compressed air and replaced the plug with a new one.

The generator starts, but runs rich ( black smoke) and won't rev high - flooded?

I removed the carb again to check the float & needle which seems to be ok and the float blocks any air when closed. However I noticed when I close the fuel tap - as the fuel runs low in the bowl - the revs increase significantly. and I can get it to rev higher by playing with the fuel tap position.

I have checked many YT channels on the honda em500, but none seem to have the problem I have and I myself don't know much about generators or carbs - any ideas what could be the problem?



IMG-20230408-WA0003.jpg
 
It is most likely the carb.. see if you can find a rebuild kit for it.. rubber and plastic bits in the carb are likely to be pretty perished by this point..
 
What you gotta do is open the carbs , turn out the jets and the tube the main jet turns into
It often has holes on the side that also gunk up

(Some of the info comes from bike knowledge so may not apply)

Put them to soak in paraffin a good while or other carb cleaner, if the carbs aren't drained when stored the petrol evaporates and leaves a gunk that does not come out by just blowing them out
You can blow them out after a while

Don't put rubber pieces in the paraffin the rubbers on the vacuum tube puff up and looks stretched and doesn't fit yhe groove it is suppose to sit in (heating it up with a haindryer shrinks them if needed)

Though the idling jet hole is moerse tiny and often does not come clean that easy
So i sometimes faf it with i tiny wire "very impatient "

If you hold it up to light you should be able to see the light shine through the hole

I often put the whole carb in a ice cream container with the parrafin for a while but remeber not the rubber vacuum tube

I also remove the float to make sure no gunk on the seat of the needle and seat as sometime the needle doesn't seal properly and floods the motor as the carb keeps filling
 
The float you have to google how many mm the float has to be and can bend the plate that the needle attaches too until you hit the spot

Did this a long time ago can't remeber the detail how you set it just remeber that they normally give the spec in mm

and i think it is how many mm the line/mark on the float is away from the base of the carb body when the seat seals (can't recall if ot is just as it touches or if the spring hass to be compressed) ,the base is part the cap seals against
 
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spiff said:
Thanks I'll look around. The generator is about 30yrs old so I'm not sure if they will have a carb kit or spares.
Click to expand...
Most of the time the jets are all the same size , apart from the holes naturally , so you would be able to find at a bike
shop /lawn mower shop easily
Take the original along or the numbers on them at least
 
leon.davibe said:
The float you have to google how many mm the float has to be and can bend the plate that the needle attaches too until you hit the spot

Did this a long time ago can't remeber the detail how you set it just remeber that they normally give the spec in mm

and i think it is how many mm the line/mark on the float is away from the base of the carb body when the seat seals (can't recall if ot is just as it touches or if the spring hass to be compressed) ,the base is part the cap seals against
Click to expand...
Tag can't be bent, it's plastic.
 
Yea then most likely the float can't be adjusted

The seat has a little pin that is normally springed so soak it to see if it comes loose it may cause the float to have to go up higher before it closes so may let more petrol into the bowl than needed

Naturally this may not apply so spray carb cleaner or soak and tap tap tap to see if it starts to move or get a new one
 

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Since that needle is stuck in most likely the carb was full when stored

So the ports the jets turn into in the carb may have gunk in too so gotta blow and hear if they are open,
 
The soak helps

Left mine overnight and blew out the next day get a carb cleaner that will have a chemical composition that probably helps dissolve this i just used the cheapskate parrafin
 
The idle jet is a bitch to get the hole open

I think i used a strand from an electrical lead wire to try and push through the hole

Can't remeber if i got one thin enough or if it just eventually got clean by dissolving the gunk

Remeber i had to remove and open the carbs more than once hence why i eventually left it to soak overnight
 
Most likely everything is stuck

Gotta get rid of that yellow glo
The problem is that gets stuck on the tubes in the carb and essentially make the diameter smaller of the tubes

I see some say they heat water mixed with lemon juice (which is an acid) in a pot and submerge the carb and it cleans of that petrol varnish

If it stands really long it becomes hard like varnish

But since you got it to start at least the pipes aren't totally blocked

Did the bike like 2 years ago
Was standing for 3.5years

Really tested my patience
 
leon.davibe said:
Most likely everything is stuck

Gotta get rid of that yellow glo
The problem is that gets stuck on the tubes in the carb and essentially make the diameter smaller of the tubes

I see some say they heat water mixed with lemon juice (which is an acid) in a pot and submerge the carb and it cleans of that petrol varnish

If it stands really long it becomes hard like varnish

But since you got it to start at least the pipes aren't totally blocked

Did the bike like 2 years ago
Was standing for 3.5years

Really tested my patience
Click to expand...
I'm getting a ultrasonic cleaner. That should take care of all the gunk in the carb.
 
Hey bud did you ever come right with this unit?


I'd be interested to buy it off the old man if he no longer has a need for it.


Trying to get a collection of mini generators going.
 
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