Walbro WT-71 Carb? (Full Version)

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Schizted -> Walbro WT-71 Carb? (11/12/2012 6:57 PM)

my walbro carb will pull fuel up the lines and back thru the return but it wont pump any fuel into the engine...?

Ive dissaymblyed and cleaned out all the ports with carb cleaner and a little wire and still nothing

why cant i get this thing to flood the eninge?



All Day Dan -> RE: Walbro WT-71 Carb? (11/12/2012 7:32 PM)

Rebuild the carb. Get the rebuild kit K20-WAT. Check the choke plate for full closure. Blow out the carb with a can of computer dusting air.

http://wem.walbro.com/walbro/group2.asp?FamilyName=WT

Dan.



Schizted -> RE: Walbro WT-71 Carb? (11/12/2012 7:41 PM)

Choke plate closes fully, Blown out the carb with cleaner, all gaskets look good except the diaphragm will be getting a hole kit soon, tried a walbro wt-340 that i knew was working on another trimmer, attached it and the purge with flown gas in and out but non of it is getting to the engine...



Schizted -> RE: Walbro WT-71 Carb? (11/12/2012 7:43 PM)

ive taken the carb off the engine and primed it and no fuel comes out of the throat of either carb



All Day Dan -> RE: Walbro WT-71 Carb? (11/13/2012 12:02 AM)

There's a mounting block between the engine and the carb. That may have a leak. Also change the gaskets that are on both sides of it. Dan.



w8ye -> RE: Walbro WT-71 Carb? (11/13/2012 12:54 AM)

Soundsas though the metering valve is stuck and not letting fuel though?

The screen between the pump and metering valve may be stuck?



Schizted -> RE: Walbro WT-71 Carb? (11/13/2012 3:59 AM)

 The Gaskets between the carb and the heat dam and engine are brand new, took the carb off and check the gasket holes to see if its all lined up, it was all ok.

Took the carb apart except for the needle seat and all that and is soaking in a carb cleaner bath over night.

Goning to local shop to look for a carb repair kit to replace all of it. and clean out the needle seat and metering valves




On another note, i added a bit of gas straight into the cylinder and hand propped the engine, it didnt want to pop really only got 1 decent put put put

i dont have the tools to do a compression test but holding my finger over the plug hole it sucks pretty hard and pushes my finger away

took the plug out and hand propped and i get a god amount of sparks popping off.



is the carb affecting the engine from not wanting to run for a second even with straight gas to cylinder?



MetallicaJunkie -> RE: Walbro WT-71 Carb? (11/13/2012 6:26 AM)

i have a wt-71 on my 3w80....im sure you know this...but you might want to make sure the metering fork is engaged on the pump.... some carbs dont have it, but this particular carb does...

what engine do you have it on?



Schizted -> RE: Walbro WT-71 Carb? (11/13/2012 8:48 AM)

its engaging, but myabe clogged its soaking and it that dosnt work ill replace when i ge the repair kit.

its on a 25cc homelite



MetallicaJunkie -> RE: Walbro WT-71 Carb? (11/13/2012 9:59 AM)


quote:

ORIGINAL: Schizted

its engaging, but myabe clogged its soaking and it that dosnt work ill replace when i ge the repair kit.

its on a 25cc homelite



see if yur local shop has one of these...they come in handy http://www.ebay.com/itm/NEW-WALBRO-DIAPHRAGM-CARBURETOR-W-METERING-LEVER-TOOL-/280341093058



Schizted -> RE: Walbro WT-71 Carb? (11/14/2012 12:23 AM)

ive replaced all the gaskets the metering fork, needle, screens everything but the little metal caps. let it soak 24 hrs in carb cleaner, blew out all ports with carb cleaner and reassemble

all it will do now is after a bunch of priming i can get the gas to climb th line to the carb but thats it, it wont fill the bulb if it does its just a tiny bit of gas.


Ive have disassemble and reassemble it 3 times to check everything, what is going on?



w8ye -> RE: Walbro WT-71 Carb? (11/14/2012 1:06 AM)

You need to take your carb to someone who works on Walbros all the time or get yourself a new carburetor?



MetallicaJunkie -> RE: Walbro WT-71 Carb? (11/14/2012 3:09 AM)


quote:

ORIGINAL: Schizted

ive replaced all the gaskets the metering fork, needle, screens everything but the little metal caps. let it soak 24 hrs in carb cleaner, blew out all ports with carb cleaner and reassemble

all it will do now is after a bunch of priming i can get the gas to climb th line to the carb but thats it, it wont fill the bulb if it does its just a tiny bit of gas.


Ive have disassemble and reassemble it 3 times to check everything, what is going on?



is it possible you might have swapped the low and high end needles



Schizted -> RE: Walbro WT-71 Carb? (11/14/2012 3:26 AM)

 I had just thought of that so tried to switch em but they are diffrent size and thread so they cant be swapped.

the fuel is not even getting to the primer bulb so im guesing that its not making it past the pump




LanceLKs -> RE: Walbro WT-71 Carb? (11/14/2012 4:23 PM)

Butterfly couldnt have gotten rotated 180 degrees? Do you see screw heads or threads when looking in carb?



Schizted -> RE: Walbro WT-71 Carb? (11/14/2012 5:21 PM)

see screw heads on both throttle and choke 



MetallicaJunkie -> RE: Walbro WT-71 Carb? (11/14/2012 5:24 PM)

one time after replacing the membranes on both sides of the carb i put the wrong membrane one ,opposite the diaphragm... it was missing the reeds/petals....the guy at the lawmower shop said it was for gravity fed setups....you might have put the wrong one on as well?



Schizted -> RE: Walbro WT-71 Carb? (11/14/2012 7:38 PM)

the fuel pump with the one way valves? the orginal was a clearish color, replaced it with the exact same.

got a black fuel pump gasket that is the extact same cut out but feels liek a rubbery material was thinking about trying that one

i feel like the valves wont open or somin... 



All Day Dan -> RE: Walbro WT-71 Carb? (11/14/2012 9:26 PM)

Here's what's in my WT-76. Dan.



Rick Sowell -> RE: Walbro WT-71 Carb? (11/15/2012 5:26 AM)


quote:

ORIGINAL: Schizted

see screw heads on both throttle and choke 

there looks like your problem, I checked several carbs that I have here and all of them the throttle butterfly screw head will face the engine and the choke screw head will face the outside or incoming airflow.
I had a zenoah that got turned 180 degrees and it would prime but not start, had to use a starter to get a pop from it. have you taken the throttle spring loose? if so it will allow the butterfly to rotate 180 degrees.



All Day Dan -> RE: Walbro WT-71 Carb? (11/15/2012 6:28 AM)

Rick, you're a genius. I took a look at my WT-76 and you are right. The screw head on the choke is visible when the choke is closed and the threads of the screw are visible when the throttle is closed. Brilliant. Never would have thought about it. Dan.



Schizted -> RE: Walbro WT-71 Carb? (11/15/2012 6:39 AM)

I think i might have figured it out, its always the simple things...

Screw heads are in correct postion, i put the rubber fuel pump on and still nothing, so then i deciede to try my old diaphragm again and wala!  it pumped gas threw both lines but not out the throat!

my old diaphragm had a little piece attached to it, the new diaphragm did not and that little piece was sealing it down



now my question is which gasket goes first  on the body of the carb 

Carb>  Gasket B->  Gasket A-> Lid

or

Carb>  Gasket A> Gasket B-> Lid


And am i suppose to see fuel come out the throat of the carb to flood the engine?



w8ye -> RE: Walbro WT-71 Carb? (11/15/2012 12:18 PM)

On the metering valve side of the carb it is Carb>  Gasket B->  Gasket A-> Lid



All Day Dan -> RE: Walbro WT-71 Carb? (11/15/2012 3:48 PM)

schizted, do not tighten those four screws too much. If you do, the gasket will get crushed and the cover distorted. What do the right diaphragm and gasket look like on the pump side? Dan.



Schizted -> RE: Walbro WT-71 Carb? (11/15/2012 5:34 PM)

 good to know i wasnt sure how tight to get those screws.

i dont know what you mean, the fuel pump and gasket look like the pic you posted of the rubber one and gasket



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