Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

This generator has maybe 100 hours on it and I use it maybe 15-20 hours a year and run it for 30 minutes a month when it is not being used. I tried to start it for a 30 minute run and it started and ran for 20-30 seconds and stopped. While it ran, there was black smoke coming out the exhaust like it was being choked and it died like it was being flooded. I took the spark plugs out and they were wet. I ran the starter with the spark plugs out and droplets of gas
came out the spark plug holes. It obviously is way too rich, right? So, what could be the problem? Choke sticking closed? Some sort of carburator adjustment? I recently tuned it up and it has a brand new air filter. I tried it with the air filter off and it did the same thing.

I would appreciate any help/ideas.

Thanks,

Don

I took the carb off today and checked the float. Everything seemed normal-clean bowl, float pin was clean and not deformed at all. I didn't check the height of the float-not sure how to do that- but it appeared ok to me just looking. It dropped down a little when turned right side up and would be pushed up a bit when it floated on the fuel. I put it back together and started it up. It ran longer than before, but rich with lots of black/gray smoke and eventually stopped. I checked the choke and it functioned like it should-rotated to choke when the start button was pushed and held and then off when released. I noticed that there was droplets and a mist of gasoline coming out of the air inlet port from the air filter to the carb that I had not put back together. There was even gas droplets running out of the air intake inlet. When I took the spark plugs out, they were wet and when I turned the engine over a mist of gasoline came out of the holes also. So, obviously too much gas still. The choke appears to work appropriately and the throttle linkage also seemed to work fine. Ideas? Can fuel pump pressure be too high for some reason and push too much fuel through the carb? Where could all this gas be coming from.
Thanks again for the help,
Don

How does it run with the air filter off?  Have you tried that?  Most generators that I've seen use gravity flow.  No fuel pump.  Something doesn't seem right in the carb.  It sounds like the main jet is pulling too much fuel which is usually caused by the fuel level being too high in the float chamber.  Did you check the main jet to make sure it's tight in it's seat?   I'd disassemble the carb entirely, clean everything thoroughly and put it back on.  Not much else that I can think of.

It runs the same with the air filter off. It does have a fuel pump-the manual I have says to check it with 12 volts to see if it clicks, but nothing about actual fuel pressure. I didn't check the main jet, but I can do that when I take it apart again. Everything looked fine with the float, but I have located the spec for the float level height, so I will check that when I take the carb apart, clean everything and reassemble it. One other thing-it has a fuel cut solenoid valve. Here is what I can find about it:

FUEL CUT SOLENOID
When the engine is turned off, it will make several complete revolutions before coming to a complete stop. Each intake valve opening will continue to allow fuel to enter the combustion chamber, but without spark occurring. If there is a hot piece of carbon in the combustion chamber, or in the muffler, engine run-on or after burning could occur. The fuel cut stops the flow of fuel to the carburetor main jet.
The fuel cut solenoid is located on the bottom of the carburetor. Electrical power from the generator activates the fuel cut solenoid when the engine switch is turned to the OFF position. The beauty of this system is that a battery is not required to power the system.
Once the generator comes to a complete stop, the solenoid will deenergize and a spring inside the solenoid will pull the needle away from the main jet.

That sounds like something that would keep fuel from the jet rather than too much fuel as it states. To test it, the book says to check continuity between the two leads and it should read 7.5 ohms. I checked it and it reads 6.9. It doesn't have a range, so I am not sure what to make of that, except that it is used to stop fuel to the jet. The generator does not run after turning it off, however.

It also has an adjustment for the pilot screw. I will set it to the standard setting, although the manual says to adjust it after the engine has warmed up to normal operating temperature.
Not sure what the pilot screw does....does that regulate fuel to the jet? I will give it a go tomorrow and set everything I can find to the specs in the manual and see what happens.

I'm not familiar with the carb you are working on.  However, the pilot jet function is to control  low speed operation (approx. the first 1/4 or so of engine speed), thereafter acceleration is passed on to the needle jet on (certain types of carbs) and wide open throttle is governed by the main jet.  If your pilot jet is way out of adjustment, it could possibly be providing more fuel than required at lower rpm.  Once the engine is running a max. rpm, it shouldn't have much of an effect on engine operation.  I'd be interested to know what's causing your problem.   Good luck.

I am going to take the carb off, soak it in carb cleaner and put it back together. The only thing I can guess is that it is a clogged air circuit in the carb or a
bad carb itself. Can't think of anything else. Nothing else would cause too much fuel, would it? I'll let you know what happens.

Just soaking the carb will not guarantee that you get all of the debris out.  I know that many will disagree but I use a very fine wire to get into small passage ways to dislodge dirt then I flush with WD-40 and blow with compressed air.  I also pull all jets and removable components to give them a thorough cleaning.   Not sure why there is such disagreement with using a small wire.   Might be due to ham fisted do-it-yourselfers breaking off pieces of wire in the carb??  Don't know.  I do know that if done carefully, using the wire will get the job done. 

I can't think of anything else that could cause fuel flooding other than the carb being out of adjustment or stuck open float needle.   Go over everything on the fuel system to ensure all hoses are good, fuel tank clean etc.  Won't do anything to solve your existing problem but will ensure the rest of the system is good. 

I cleaned the carb and all the parts. I used a small wire and compressed air in all the air passages. Then I blew threw each one with a plastic tube and they all were open and allowed the passage of air. The float was not waterlogged and the needle and seat looked like new. After putting it back together, now the generator won't run at all! It turns over and tries to start, but won't. The plugs look wet, but there is not all the raw gas coming out of the spark plug holes
or out the carb air intake like before.

I guess I will check the spark, but can't imagine that is suddenly a problem. I think it is time to remove it so I can access everything and either get a new carb or take it in for service.

Just a long shot but have you completely drained the fuel from your fuel tank?  I've seen similar problems caused by water.  Just this summer, I was trouble shooting a problem with my buddy's outboard motor.  Spark plugs looked wet and smelled like fuel but it was mostly water.  His fuel filter was completely full of discoloured water so there was no visible separation of fuel/water to be observed.  Emptied the fuel filter, & got the engine running.  When he hooked up his own fuel tank to the motor, same problems began.  We poured out the gasoline from the tank into a clear container.  Half the contents was water!   Not the first time I've seen that either  

Been gone on vacation and moving my son, but I have recently done a few other things. I cleaned the fuel tank....there was a little sediment, but no water that I could detect. I checked the fuel lines and put a new filter on and put fresh gas in with a fuel stabilizer. I checked the spark and it has good spark to both plugs. I sprayed some starting fluid in it and it fired on that, so I tried it with gas and it tried to start, but quickly dark smoke came out the exhaust and it wouldn't start. I noticed fuel at the inlet of the carb again and when I took the plugs out they were wet. When I turn it over with the plugs out, gas droplets come out the spark plug holes.

Where to go from here? It obviously seems to be a fuel problem. Didn't you say earlier it could be the carb? Do they just malfunction out of the blue like that? Is some air passage closed that floods the carb with fuel?

Sounds like the carb is pouring raw fuel into the engine.  If your float needle isn't stuck open,  I can't see any other way that the fuel could be getting in unless you have an enrichening circuit (choke) that is dumping raw fuel into the venturi.  That's basically what an enrichening circuit does.  Pull the carb and go over it with a fine tooth comb.  Check everything, pull every jet, clean every passage.  If there is an enrichening mechanism, check that too.  On the Mikuni carbs that I work on, one has an enrichening circuit.  there's an O-ring in there that if it fails, fuel will seep past it and create a rich condition.  If you take the carb completely apart, you might as well put in a  a carb kit if there's such a thing for it.  How about posting a picture and a link for info on that particular model of carb?  It would help understand it's operation a bit better.