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

have a coleman powermate 1600 generator that last year when we used it we ran the gas tank dry and it shut off.this year during deer camp we started it up and it surges real bad at full speed.it runs better with 2 notches of choke on so i'm assuming the high speed jet is obstructed.this jet is fixed and located vertical in the center of the float bowl and holds the float bowl on.anyone know how many passages in it and what to look for?. also  this generator has but one speed and goes to the governed speed when started.there is a mixture screw i assume is for idle mixture that is adjustable.what is the initial mixture screw setting and how do you dial this mixture setting in if the engine only runs at governed speed?also where can i get a new gas cap or fix the one i have.it is a vented cap that had a foam cover on the bottom that fell off and now the vibration causes the gas to spill out the vent. the only thing i know about the engine is that it is a model 93400 and 3 1/2 hp. thanks in advance for any info. mike janesville wi. 

       It is confusing to think of the carb circuts as low and high speed when working with a "fixed speed" governed engine.... Note all small engines are governed,  Generators on smaller engines or lower cost generorators are fixed to reduce cost.....meaning that the Engine is always running whatever it takes to keep the engine at 60 hrtz  and between 110-120 volts...  (roughly about 3300 rpm)

Now your problem...   surging

Your engine is surging because it does not have enough fuel on the low speed jet ......... You are confused because the motor always runs at the same speed?    Well,  your engine is under no load without anything plugged into the generator.   Because there is no load in the generator the engine really requires little to almost no fuel to keep the engine at the 3300 rmp..  As soon as a load is applied the govenor has to open the throttle to maintain the fixed rpm..    This action is kinda like driving down the street idleing, when you come to a hill you need to push the gas peddle down to continue to climb...

Now the carb... your genorator is running under no load in the low speed cirtcut/jet......  when the govener sees that the engine is not maintaining rpm, the govenor opens the throttle to allow more fuel to the engine..    This action of opening the throttle allows fuel to rush into the motor and produce more power and the rmp increases sharply.....

But... the govenor senses the engine is running past its governed speed and starts to close the throttle,  then engine is not getting enough fuel through the low speed circut/jet  so it reacts by opening the throttle again and starting the cycle all over again...

You say you have a low speed jet on your carb?...  if so try to turn it counter clockwise about 1/8 turn... this may fix the problem..  If not the carb may need to be cleaned out .  You say the carb was run dry last time ran?.... if so the deposits may be very little if any, try to run the motor with some SeaFoam cleaner in it for a while and see if the complaint goes away... If not, let us know the model type and code of the engine and we will come up eith better info...

Good Luck,

Friiy

i initially had the low speed set at 1 1/2 turns out from bottomed and tried increasing the setting to 2 turns which made very little difference.i have taken the bowl nut/high speed jet out and cleaned the 2 side and one center orifices thoroughly with carb cleaner and a small wire. this did help some!i have about 1 1/2 ounces of sea foam in the fuel tank and sprayed some directly into the carb while running.it has smoothed out some and runs kind of like it use to before the bad surging but as it is now if i put the choke on the second notch it smoothes out(no muffled  poping)and on the third notch of choke the rpms increase perhaps 50 rpm and seems to run even better.my options are to dismantle the carb completely and clean everything and reassemble it and see if it's fixed or run it like it is on the 2nd notch of choke.i wish the high speed jet was adjustable and not fixed ! ...................................................just got done tearing the carb off and completely cleaning it with choke cleaner and reassembled it.that's where the problems started again! it got worse and then it would clear itself. tok the carb off again and redid the cleaning and it still acted up. then when it killed i shut the fuel off and disconnected the fuel line and noticed it was barely trickling any gas.i ran the fuel line into another hose and then cracked the gas cap.once the cap was loose gas started flowing again.the original gas cap had a small cylinder of foam rubber covering the vent so the gas wouldn't splash out the vent.the foam fell off and the cap started leaking so i spent the rest of the afternoon chasing down a cap.i found a vented cap but it had a white plastic washer and it wouldn't seal on the plastic tank. finally put it back together and still not satisfied with the tank cap.iffy it it seals or not!