Yamaha Electrical Supplies - Page 8 - Answered Questions & Fixed Issues

Isolate problem first! Change fuel filter and check to see if the gas is contaminated or at a low level in the fuel tank. Until the engine runs for a while with the gas coming out as it should, you can't know if sparking is the problem!

clean tank fuel lines air filter and completely clean all carb parts and jets just did mine runs mint now did the same thing i also put in a new spark plug changed the oil a good once over goes a long way just take your time use a good carb cleaner like crc or gumout and check the jets they have small holes on the sides that can clog up hope this helps

you don't, its self adjusting, if it feels slack you prob need a new chain or guides.

Failing electronic ignition or a RPM limit has been reached.

Those cost money. Good luck. Owners or operators manuals are usually free.https://www.samswebsite.com/

there are a couple listed on ebay in the $10 range

Doe's it have a thermal couple on it? If so it could be bad and when it heats up it is killing your power.

replace the needle and seat in the carb the fuel we now have leaves a residue behind and the needle and seat don't seal after doing that add a shut off valve and turn it off and run the engine out of gas when done using it

unplug it and see if the light changes if not ground the wire out if there is no change its wiring if it changes its a bad sending switch

Yep. I have a few ideas.

1) Fuel system is vapor locking. Make sure that the fuel lines are routed as they were from the factory. Remove any aftermarket filters that you may have installed.

2) Fuel system is being pressurized. Most common when the vent on the fuel tank is clogged for whatever reason. Pressure builds up, and fuel is forced through the carburetor, flooding engine. Easiest way to check for this one is to crack the cap on the fuel tank after the engine has started having troubles running. If starts running better (may take a moment), time for new vent.

3) Engine oil is low. Friction is increasing, engine damage is occuring.

4) Engine oil is not circulating. Oil pump (if equipped), clogged filter, etc. Engine damage is occuring.

5) Air intake for cooling on engine is blocked / clogged from debris. Very common, actually, you would be amazed how much debris accumulates here on all engines even if they are operated in environments where it normally wouldn't be suspect. Remove the cover and clean it out. You may not see debris, but it could be coated with dirt / mud / etc.

What elevation are you at? Start with simple things such as clean the air filter, fresh gas, clean/replace spark plug. Also check oil level most generators have a low oil shut off yours may be attempting to shut down

check the engine RPM as well it should be lower than 3600

sounds like the fuel pump is bad, can you pull off the hose and test it?

I hope you have not moved the genny from lower to high altitude b cause the carbs of these gen sets are tuned at the sea level and they give their best performence up to 1000 meters or so in altitude from sea level if you hav'nt moved the generator then check the air fuel mix screw on the carb that screw controls the the oxygen supply required inside to burn the appropriate quantity of fuel take a screw driver and adjust by rotating it anticlockwise on idle with eco switch on then put it on 75%load and try adjusting the screw both ways clockwise and anticlockwise with switching the load on and off with eco throttle off you will find a point where the engine will run smooth but mind it the screw has to be moved very slowly either side usualy these problems accur on high altitudes when the oxygen suppy goes less then the jet in the carb is to be reduced and air fuel mix has to be adjusted which is called re jetting of the carb You say you have cleaned the carb may be accidently while cleaning the air fuel mix screw might got disturbed just check

Remove & Check Float bowl on carburettor for any foreign matter. If there is any, it could have got into jets causing engine to run lean (only run with choke) and not be able to carry load in this state. A cleanout of the carby would not hurt and check the fuel tank for any sediment as well.

replace it

This is official site: http://www.yamaha-motor.com/outdoor/products/modeloverview/cat/2007/55/model_overview.aspx

40hrs? I'd look at the exhust.There is a screen that fits INSIDE your exhust.A small flat tipped screw driver should pry it out easy.In chainsaws they're used for spark arresters,the same on these I think.Quick wirebrush and your exhust should be able to flow and not back up. I've had my 2400 7 yrs now here in Alaska,out in the woods where I live.I need a Boost Control Unit,teach me for not using a ground wire,I burned a pin out in my unit.$800 part for a $1,300 generator.I really really like mine so I'll buy another and keep looking for a used one online.

Hi,
The simplest way I have found to fix problems like that is a product called "mechanic in a bottle"

http://www.b3cfuelsolutions.com/html/mib.html

or Click here to go to the link

I get it at Home Depot, but don't know if you have one close... you can get it online...

Place this stuff in the fuel and run following the directions... it will get the engine running right again...

heatman101

Now if the genset stabilises with a load but keeps shunting when there is no load it is possible that you need to do a service check or overhaul of the engine.
1. Make sure that the oil is clean , if low or clogged replace the oil.
2. Check the fuel line and the fuel/air settings . If the engine is HUNTING then there is a setting fault of the mixture or there is dirt in the carburator ports that does not allow the fuel to be flowing with the right pressure . It is best to remove and clean the system.
3. The Spark plug is another reason, if the plug gaps are low, if the spark plugs are bad, insulation is faulty the power will be reduced as it will hunt.
4. The genset RPM is monitored by a governor which allows a slight throttle adjustment when the load increases. So make sure that the linkages to the throttle vavle is free and moving.
5. the choke must be kept closed, check the spark plug to have an idea of the firing.Finally check the fuel, check for impurities in the tank.
I am sure one of the above tip must solve the issue.
Thank you for using FIxya.