T140E 1978 starts runs at idle, quits on take off. Replaced floats and electronic ign. checked tank cap, fuel flow all ok. Replace main jets with #200. It seems to starve for fuel at take off. Been throught Ignition, fuel system three times and can't get a handle on this one!! Anyone got and idea, or theory?

This is likely to be a fuel starvation problem.
Fuel is fed from a reservoir called the float bowl. This works pretty much like a toilet cistern with a float to cut off flow once it fills. Once the bowl empties and doesn't refill due to a blockage, the engine will cut out.
Clamp off the fuel line or turn off the fuel tap. Remove the bowl, unclamp the line or turn on the tap, and check fuel flows freely. If it doesn't, there is a blockage in the fuel line which you need to trace.


Another scenario is that the main fuel jet is blocked or semi-blocked. This can cause the engine to run ok when idling (since the idle jet is ok and not much fuel is required), but cut out as you throttle up. This is because more air is sucked in, but not enough fuel is drawn from the main jet due to the blockage. So the mixture is to weak and the engine stalls. The jet can be cleaned with compressed air or ideally a carburetor cleaning aerosol.

See my comprehensive guide for getting stubborn lawn mower or other small engines to start:

http://hubpages.com/hub/Why-Wont-That-Lawnmower-Start

most likely your main jet in the carb is clogged, water in fuel, or a plugged fuel line, filter, or plugged in the tank where the fuel line connects. it is common to have a plug where the fuel line exits the fuel tank if there is a 90 degree turn in the fitting, debris may build up in the 90 degree area. check by replacing old fuel with new, then pull fuel line from carb and fuel should flow freely, look for a blocked fuel line if it does not flow. it it does flow, pinch off fuel line then remove the float bowl to drain remaining gas and give acess to the main jet. the main jet is located in the side or bottom of the lowest protruding area into the float bowl. run a thin wire like a guitar string thru the small jet hole to unplug, then squirt a little wd-40 thru jet hole to visually check flow. next, unpinch fuel line and fuel should flow from carb into float bowl area. then check to make sure the fuel stops flowing when the float is gently lifted to the top of its travel. if problem in this area, remove float pin, float, and needle valve and check for blockage in the needle valve seat. clean out with wd-40 and reassemble, add fresh gas and give it a try!

when this happens, the engine only runs long enough to consume the gas you manually put into the carb. The engine dies because the main jet of the carb is plugged or there is water in the fuel system. repair by dumping old fuel from tank, then remove float bowl on carb. this will drain remaining fuel in carb and give you acess to the main jet as well. Main jet will be located in the protruding part of the carb that sets as the lowest part in the float bowl. locate the jet either on the side of this protruding area or set into the bottom of the protruding area. use a thin wire like a guitar string to run thru the small hole in the center of the jet. then squirt a little wd-40 thru the hole and check visually to make sure the jet is clear. there also could be a problem with the float or needle valve that allows fuel to enter the carb and regulate the fuel level in the float bowl part of the carb. check this by letting the float drop while bowl is removed and gas should trickle down from the needle valve, if it does, then hold the float to the top of its travel but do not force it beyond the stop. fuel should now stop trickling from the needle valve. if it does not stop, then you probably have a little debris clogging the needle valve preventing it from closing completely. this usually causes a flooding condition. By your description, this is not the problem as your mower slound as it is starving for fuel. if no gas flow from needle valve while float is at the bottom of its travel, then you may have a clog in the fuel line, filter or in the tank where the fuel line connects to it. remove fuel line from carb and fuel should flow freely from this hose. if not, check for clog in the fuel line-fuel filter system. hope this helps! oh y, the last steps require a little fresh gas in the tank!

hi there harryandmeli
sounds like you still have a restriction in your carb or the float level is not right
check all the opening s and jets carefully, particularly main jet and emulsion tube air bleeds
and the idle air bleed , and idle jet, is the tank clean and no water ? , is the tank breather working ?, make sure gaskets at carb flange are ok - no leaking of air , make sure air filter is not blocked ?

provided compression and spark ok,( spark should jump a 6 mm gap minimum ) to pass a coil test and fuel flow from tank to carb is good , these engines have hydraulic valve lifters and like 10w/30 kohler oil , everything being = engine should run good

remember F A C T S

F = Fuel , A = Air , C = Compression , T = Timming , S = Spark

take a look

cheers hope it helps

pauly46

Hi and welcome to FixYa, I am Kelly,

Download this manual:
http://www.cpdonline.com/692509.pdf

First things first turn off the fuel selector if there is one.

See figure 10 on page 14. I think your going to have to remove the float bowl and the idle screw and use some carb cleaner in the idle screw hole. BEFORE you remove the idle screw turn it "clockwise: gently counting the number of turns until it just stops turning. (write it down as IDLE) DO NOT force it closed. Then remove the idle screw for cleaning. Also remove the main adjustment screw but loosening the nut ONLY that retains the float / fuel bowl. (do NOT turn the main fuel jet until after removal. Again count the number of turns it took for the jet to just stop turning. (Write that down as MAIN) Spray carb cleaner into the idle screw hole and into the threaded area where you removed the bowl nut / main fuel jet. What ever you do if your carb has any Welch plugs in it DO NOT remove them even if the manual tells you to do so.
One thing to check is that your carb mounting bolts are tight and that gaskets are in tact. The symptom your describing can be caused by a bad intake gasket also. It is ok to loosen the carb and slide it away from the head gently and inspect the gasket. DO NOT disconnect any linkages, just inspect the gasket.

After cleaning things up (jets) remove the fuel supply hose form the fuel inlet fitting and leave the float itself in the down position. Spray carb cleaner from the float needle are UP to the fuel inlet manifold. You are attempting to free any debris from the float needle seating area and flush it out through the fuel inlet. Usually you DO NOT have to remove the float and float needle to do this but there are exceptions when there is a large piece of debris in the float needle area. Usually if there is debris here the carb overflows. I do not think you have an overflow problem at this time.
Reconnect the main fuel line. Briefly turn ON the fuel selector and as fuel flows check that as you raise the float to level the fuel shuts off. Turn OFF the fuel selector. If you are not getting good fuel flow here inspect the fuel tank outlet port and fuel filter.
Reinstall the main fuel jet into the bowl nut until it is closed then turn it counter clockwise the number of turns you wrote down for MAIN. Reinstall the float / fuel bowl and main fuel jet but make sure the inner gasket that goes between the bowl and the bowl mounting nut is installed (2 ea usually one inside and one outside the bowl. Install the idle jet screw until it just closes and then turn it counter clockwise the number of turns you wrote down for IDLE.

If you have difficulty with mixture jet adjustments the pre-sets are on page 20 of the manual.
If you find that your going to have to completely tear down the carb and overhaul it the steps are in the same section just past the pre-sets.

Turn ON the fuel selector and attempt a start.

This usually fixes most Tecumseh carbs.

Let me know the outcome please. And if you need parts I can help you locate an on-line source but most lawn more repair shops will have overhaul kits for your engine. I will need your engine number to get you the right parts manual.

Thanks for choosing FixYa,
Kelly

your problem is a clogged carb. clean float valve, main jet and idle circuit with a can of spray carb cleaner.

disconnect fuel hose at carb and see if gas flows.

reconnect hose and open float bowl drain valve. If no gas tap on side of float bowl with plastic end of screwdirver to free up float.

still no gas? remove float bowl and try to shoot carb cleaner into the fitting for the gas line from tank.

if gas flows now then put it all back together and it should run

if not then remove carb and clean carb passages, main jet, idle circuit.

Obstruction to fuel flow is a popular cause of this symptom. The metering passages in the carburetor are very small and it does not take much to clog or partially block them. Depending on how comfortable you feel doing the repair yourself you will need to remove the carburetor to clean the main metering jet as well as the idle jet circuit. The main jet is accessible once you remove the float bowl and the idle circuit is generally accessible by removing a phillips head screw located on the top side of the carburetor. This can vary depending on the specific Honda engine you may have. Also be sure you have fuel flow to the carburetor, if the tank vent in the cap is not working properly you can lose fuel flow to the carburetor. Hope this gets you in the right direction.

Hi and welcome to Fixya I am Kelly. This symptom is typical of fuel starvation. It can be caused by

1. A dirty fuel filter (if installed)
2. Debris in the bottom of the fuel tank
3. Fuel shut off selector not all the way on or debris in pet-c^ock bowl. This is located on the bottom of the fuel tank.
4. Float needle assy not allowing proper fuel flow in the float bowl
5. The fuel supply line or the plastic "Y" just before the carb is cracked and air is being introduced into the system as the fuel hose swells from heat.

I really think you have a fuel supply issue. A break down can be found here of your carb:
http://www.boats.net/parts/search/Honda/Generator/0/EU3000IS%20A%20GENERATOR,%20JPN,%20VIN%23%20EZGF-1000001%20TO%20EZGF-1079999/CARBURETOR/parts.html

Fuel tank cap removed

You should be able to remove the angled drain screw (Item 6 above link) in the bottom of the float bowl and have fuel flow freely out of the hole. (I use spray paint can cap / lid to catch the fuel. If you can not fill the spray paint cap to the inner circle of the cap in one continuous attempt there is a problem with fuel supply ( 1 - 5 above )

If you can avoid it DO NOT remove the carb. Getting all the linkages correct during reinstallation is tedious even for seasoned techs on this generator. You can safely remove the float bowl and check for debris / give the jets a blast of carb cleaner. If you do use carb cleaner also direct a shot into the fuel hose connection (hose removed) on the side of the carb with the bowl off. The jet is in the very bottom of the center post.

PLEASE do a leak test before starting the engine with the fuel selector on. (Safety issue)

Make sure you replace the fuel tank cap before starting the generator.

Thanks for choosing FixYa.

Kelly