Carb Float Bowl Removal By merlindad5262 (Read 2,272 times)

[merlindad5262]

I own a Tao Tao 50cc scooter.  I am having problems with starting the engine and how the engine runs once it is started.  I bought it from a friend of a friend, I suspect that the problem may be related to the scooter having sat for a period of time and that allowed gasoline evaporation from the float-bowl which causes a restriction to develop on ALL of the parts inside it.

To inspect the carb for this condition, I am struggling to find a method to remove the three fasteners which secure the float-bowl to the carb main body.  (I have many years of experience as a mechanic/technician.  I was "employed" in the USAF as a Hydraulic Repairman/Technician on fighter weapons systems.  I also was a Engineering?Quality Control Tech @ an Aerospace Fluid Power vendor/contractor.  I mention all of this because I believe that it is important to be familiar with one's background when discussing simple BUT very challenging technical problems.)

I have removed the carb and removed the plug which was installed in the cavity where the Throttle Mixture Adjustment Screw is located. I accomplished this mod because adjusting the valve MAY correct my problem.

However, I am looking at saving myself time and effort by inspecting the component parts that are included inside the float bowl. NOTE: The fuel delivery circuit has a vaccuum hose connected to a diaphram shutoff valve. That condition does NOT allow the fuel flow path to be manually closed. That design feature  is a poor choice as it can lead to the scenario of 'varnishing'.  I have discovered and corrected many examples of this on lawn mower engines and motorcycles that had been stored without closing the manually operated fuel shutoff valve. 8(

I have tried solvents : 70% Alcohol, Acetone, and the careful application of heat using a hand-held butane torch.  None of those methods corrected my problem!!!

So, does anyone have a method/suggestion to clear the internal cavity of the three screws? I have photos of the configuration and are willing to share them, if someone requires them.

I need "an F4 Mechanic" - please? My database is empty and I have no direction to pursue.

[Alleyoop]

The three screws your talking about do you mean the two jets and the vent? Or are you talking about the screws to take the carb bowl off to get inside.
Alleyoop

GET A CAN OF SPRAY CARB CLEANER THEY COME WITH A THIN STRAW TO GET INTO THE PASSAGES.

If your talking about the 3 holes in the picture below, the one on the LEFT with no slot is the VENT tube, you will notice your carb has a hose near the top of the carb curved down about a 1 inch or so that goes there.
To clean out the jets Unscrew them and take them out and make sure you can see daylight through them.
Then with the Jets STILL OUT spray into the holes where the jets screw in and Spray should come out as in the following pictures.

[merlindad5262]

The three fasteners which secure the float bowl are the ones I am struggling with. None of the places/parts you mentioned apply - Sorry.

How can I send you a photo, please?

[Alleyoop]

TO POST PICTURES ON THE FORUM YOU NEED A HOST: YouTube, Tinypic, Photobucket and many others are around to use.
Here is how to use a couple of them:
scooterdoc.proboards.com/thread/10064/post-pictures

Ok, do the screws have the head on them or have the heads been cut off?

If the heads have been cut off then you will need a BACKOUT DRILL BIT to unscrew them out and then go to the hardware store and buy screws to replace the beheaded screws.

If the heads are still on there then put the screwdriver in the head and give the Screwdriver a Good wack on top to loosen the threads inside. If the slots are all messed up then use LOCK PLIERS to loosen then.

[merlindad5262]

The screws have in internal hex or torqx configuration. You mentioned a "back-out drill bit". I had a set of left handed drills which I bought from a MAC Tools dealer many years ago when I worked at a Caterpillar Dealership in Texas. I wish I still had them.

Your suggestion gave me an idea that may work. I can make a 'removal tool' out of a long shank hex bit that is used in a drill or a hand operated hex bit driver.  Your suggestion about 'shocking' the fasteners with a hammer and a punch was a step that has been used by me, frequently.  Blue Loctite will break if it is applied to a fastener's threads.  The red or green is another story tho'. /wink  

I'll let you know if I succeed using the tool I described.

And, thanks for your time and attention....I am not as nimble as I used to be. I 'wore my hands and knees' out working on aircraft. Forty years later I figured that out!

I am a Jack-of-All-Trades, but a master at one.

[Alleyoop]

HAHAHAHA, Great, where there is a will there is a way and YES most of us are Jack-of-All-Trades and MASTERS OF NONE..LOL. But we try and we somehow succeed.

Ah so the screws are special hex star types so as not to make it easy for rookies to get them off. I have kit of those different shaped screwdriver bits in many sizes and many shapes. I needed them for something and had to buy a set.
Alleyoop

[merlindad5262]

Me too..I have a 36pc. set of long shanked bits that I bought many months ago. I was repairing a Sony Play-Station 3 console game system and there was one torx fastener that was installed in a blind hole approx. 1.5inches deep. I did not have the tool to remove it. It was cheaper in the end to buy a set that included the one I needed AND all of the other drivers, too. Experience is a valuable asset.

[cyborg]

You can send them to me,,,[e-mail],,,,or via text 805-217-3716

[jerryscript]

You can also use a dremel grinding disc to cut a slot across the heads of those screws and get them out with a flat tip screwdriver of the appropriate size. I personally replace with allen head screws.

On the subject of loc-tite, ever seen yellow? I've got it on my 50cc rear axle, it's either yellow loc-tite or the assembler didn't get a restroom break that day!

[merlindad5262]

@ jerryscript : I have used the yellow color Loc-TiTe. I am not certain as it has been many years since I was a CAT Mechanic, but I recall using it during my tenure.

What I do recall is : in the order of use vs color it was, RED(permanent assembly), yellow(Semipermanent), blue('liquid lockwasher').

The blue is released by striking the head of the fastener with a hammer. The yellow and red were BOTH released with applying heat. Red was only used when a bearing race was installed. The CAT method I learned to accomplish removal of a component part where RED had been applied was all about a DC arc welder, NOT a rose-bud oxy/acetylene torch.

[tvnacman]

gee I feel for the Misses you guys only screw one way .

John

[jct842]

I wouldn't put heat on a carb to release locktite, there is some plastic inside. Just go with a dremel, I have a lot of those diamond bits and wheels and would go for some sort of slot. You could get another carb as lots of people do but me I am cheap and why toss a perfectly good carb just because it has some bastard DOT required screws.

[merlindad5262]

Okay, I finally got back to the scooter carb project.  I managed to remove the 3ea cap screws which retain the float bowl to the carb body.  I did not see any contamination or assy errors.

I cleaned all of the component parts using acetone - the stuff stinks like Hell and is a huge fire hazard BUT it cuts through all the varnish that gasoline leaves when it vaporizes.  I reassyd the carb and reinstalled  the carb.  It took 5 kicks to get it running.

Now, I am having issues with starting the engine w/the kick-starter after it has been running long enough to get to oper. temp.  I have to open the throttle fully, to get it to start.  When the throttle is used past mid-rpm range, the engine bogs and stalls.  I have adjusted the idle mixture screw to 2 1/2 turns from the spot where it seats.  The engine idles fine and will pull to higher throttle positions IF the throttle is rotated at a slow rate.

However, IF the throttle is opened at a fast rate, the engine bogs and stalls.

I am gonna check the valve adjustment with the engine temp. cold to eliminate that factor.

I welcome any ideas that will lead me to resolving the issue.

I always seem to have to "build-a-watch" with IC engines.  I certainly would rejoice if I ever break this cycle of Luck....js 

[Alleyoop]

It is not your valves, it is to much AIR coming or not enough fuel when throttle is opened at a fast rate. Usually it is to much air, make sure you have the Air Filter in place.
First adjust the carbs fuel mixture by following this procedure:
And do the testing on the Center Stand when good on the center stand then jump on it and see how it takes it with a load.
Alleyoop

scooterdoc.proboards.com/thread/1499/4ts-carb-tuning

[cyborg]

i think one of the jets is not clean enough