Tip & How-To about Garden

Cleaning the fuel float bowl

Note: this procedure will often cure no start issues and or surging issues, or once done a little running after the fact will clear up surging issues as well.

Often gas with ethanol will cause gunk build up in the float bowl making your mower run badly and have a 'surging' behavior especially at low idle speeds, or cause it to not run at all (almost all gas has ethanol as an additive now for 'emission' reasons so assume you have it unless you KNOW you don't). This can take as little as a few weeks or a month or two of not running to happen. Frequently a simple float bowl and carb cleaning will resolve these issues completely or at least to get you back to a running point.

To clean the float bowl area, it's best to remove the carb. (make sure you pinch off gas lines with a vice grip or similar to keep it from spilling out and remove things carefully to avoid breaking seals on the intake)

Tip the carb over a catch basin or oil drip pan and turn it this way and that to pour as much excess fuel as you can. If your carb has a electric solenoid or an overflow screw on the bottom, removing this will let you pour fuel out of the bowl area.

To begin cleaning, Turn the carb upside down. Typically there are 2 or 3 screws that hold the bowl to the bottom of the carb. Do ALL of this over a nice metal tray that will catch any falling parts like small screws, carb jets, springs, plungers, etc.

Very carefully undo these screws and work the bowl until it breaks free of the seal

gently pull the bowl off the bottom of the carb. and you should see the float mechanism and main jet sticking out toward you. This visible area, all the orifices, and the bowl you removed are what you want to clean.

ANY orangish discoloration, sediment, or other gunk that is not obvious parts of the carb is bad news.. or good news because you're about to remove it and you found a problem that was worth fixing. If everything is clean, shiny, and aluminum and plastic looking, all is well in there, put it back together and move on to other DIY projects. :)

To clean it out assuming you saw at least a little orangish discoloration, a good pressurized can of carb cleaning spray is GREAT... HOWEVER, do not let carb cleaning spray get on ANY gaskets or rubber seals. The chemicals in carb cleaner will expand the rubber and make the seals not fit properly anymore and ruin them. (beware there is a TINY, impossible to see rubber seal on the plunger for the float so you MUST REMOVE THE FLOAT if you want to use carb spray to spray the metal on the carb or the jets while they are still on the carb. It may be better to just use a little gas in a metal tray and a soft toothbrush to scrub things off and clean them out. Typically it's just a pin you have to slide out in order to remove the float and plunger, it's sometimes a little tricky getting it back in just right.

You can also use your air compressor spray tool to blow out passages and dry out parts you are cleaning and it's great to blow out all the orifices you see in both directions ... BUT ... watch out because it is easy to accidentally blow out the jets and lose them! Also, wear eye protection ... seriously, do it, even if you're not using compressed air.

Once you have cleaned everything, make sure no little parts are in that handy metal tray you worked over the whole time. If there are any, find where they belong and put them back. Nothing in there is unnecessary... nothing!

Once you put it all back together, the carb will naturally refill with fuel and you should be able to start right up after a few seconds of cranking.

Any residual surging will often clear up after some run time, I like to use a little mix in gas carb cleaner after doing a carb cleaning. If my tractor has sat more than 2 months not running, I often check this before even trying to start to make sure I don't pull any gunk that did build up into the jets and clog them. Cleaning the bowl is easier than cleaning the orifices!

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1 Answer

Buick Lesaber, Lower then 1800rpm most time runs fine, Once in while surges high rpm's like driving fast 1900 & above rpm bucks /2100 smooth's out.


Need to take to a shop with a GM tech 2 or higher scan tool. These tools can actually display various sensor readings and voltages in real time and can be used while driving the car to recreate the issue. These are super expensive scan tools so most shops don't have them. Call around or bite the bullet and have a dealer do it. The money you spend on a correct diagnosis will be saved by not throwing random parts at it based on guess work.

Nov 01, 2016 | 1995 Buick LeSabre

1 Answer

When engine warms up it start to surge


Engine stalls cold or RPM fluctuates at idle up and down or dies near idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve but always run a OBD2 fault code as well as the cleaning procedure. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control. If the above cleaning doesn't cure your issues you need to have the computer controlled automatic idle speed control system diagnosed and repaired by a dealer or electronic engine control repair shop.

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1 Answer

LTH1536 engine surges


We had some issues in the UK like this, it was a fuel issue, there is very little gravity feed from the tank to the carb, we were fittind an electric fuel pump which cured the problem, might be worth checking out.

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I just changed the water pump, thermostat, and flushed the heater core. I ran the car for a while with the surge tank cover off and kept filling it. As soon as I got on th e-way it overheated.


The surge tank should only have a little water in it, not full. I hope you didn't overfill it, this can cause your problem, but I would look at the radiator and make sure it is not plugged and your cooling fans, make sure they are running as well. Then last but not least your water pump may be bad even though you changed it, check for good flow through the radiator, if flow is good and strong then check the fans. You have already done most of what can be done, make sure the thermostat is not in backwards, in fact take it out and see if the car runs cooler, this will help pinpoint the issue also.

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1 Answer

from canada,heater blows warm heat in cold weather thermo replaced heater hoses are hot


one thing to remember about these particular engines is how to bleed them and that the casting when these are made leave behind some "mud" that can cause the same issue. start by flushing the system with a good chemical flush (follow the directions, about $10 U.S.) and when bleeding turn the heat on to high allow for engine to warm up with the resevoir cap off (please be careful).once the vehicles temp guage begins to rise, note the level in the resevoir and add if neccessary. replace the cap and hold to about 2000 rpms for a few minutes (not allowing the temp to get a little above half). note the temp coming out of the vents. there is a little bleed screw on the thermostat housing. it is brass so be careful not to damage this piece. when pouring in the coolant open this bleeder and allow for fluid to flow until no air bubbles are visible. then procede on. this should cure the issue as long as there are no other control issue faults (interior). cheers

Jan 21, 2010 | 2003 Chevrolet Malibu

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