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Marlin Dunham
New member
Username: Salchapete
Post Number: 1
Registered: 04-2007
Posted From: 209.112.150.206
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 17, 2007 - 11:34 pm: | 
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Last fall I returned home after a run with Max II and as I parked it, it farted and died. Would not re-start. I left it sit all winter. Last week the snow mwlted enough to get it into the shop. I discoved I was not getting fuel. I blew thru the fuel lines and hooked it back up and it started. But it will not do anything but idle with a short burst of throttle and than it dies unless you add choke quick. It has a Walbro WD carb. I rebuilt it and it still did the same thing with one difference. This time it ran for a bit, shut off and the crankcase filled with gas. Any ideas? Also, on the side of the carb there is a (L) adjustment screw and a hole where the (H) is. Is it supposed to have a high idle screw? Doesn't appear to be threads in the hole. |
isaac eisenman
New member
Username: Tropicjungleboy
Post Number: 5
Registered: 03-2005
Posted From: 201.224.139.175
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 18, 2007 - 01:17 am: |
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marlin: aparently the needle is wrong setting ( to high). or not seat properly and fuel is moving into the intake chamber by gravity. proper settle on needle is flat with carb base. |
Marlin Dunham
New member
Username: Salchapete
Post Number: 2
Registered: 04-2007
Posted From: 131.39.248.7
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 18, 2007 - 03:31 pm: |
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OK Which needle are you refering to? The only needle in the carb it inside the carb and not adjustable as far as I can see. Unless the screw on the outside goes into it. But I don't think so. I think the screw on the outside is Fuel/Air mix. Does anyone know if the Walbro WD is supposed to have both a low and a high mix screw? |
isaac eisenman
New member
Username: Tropicjungleboy
Post Number: 6
Registered: 03-2005
Posted From: 201.224.139.175
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 18, 2007 - 04:26 pm: |
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marlin: i do refer to the inside needle. and yes, it must be adjusted by twist the baffle plate below it. the right setting is when this plate get even with top of diafrag wall ( caRBURATOR BODY ). the idea is to close the fuel pasage when diafrag get on suction ( vacuum) mode. when diafrag get on pressure mode then the center metallic pin press agains the baffle and open the flow to the carb ventury. carb ventuty is restricted by the fuel/air mixture screw. |
Sean McConnell
Member
Username: Bookm
Post Number: 49
Registered: 09-2005
Posted From: 69.159.216.86
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 18, 2007 - 05:18 pm: |
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Here is my carb "bible". You'll need Adobe Acrobat Reader to view the .pdf. I'd recomend printing if out make a booklet out of it.
carb manual: www3.sympatico.ca/sean.kathy/CarburetorManual.pdf |
Sean McConnell
Member
Username: Bookm
Post Number: 50
Registered: 09-2005
Posted From: 69.159.216.86
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 18, 2007 - 05:21 pm: |
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Hmm. link not working.. cut n' paste this line to address bar:
www3.sympatico.ca/sean.kathy/CarburetorManual.pdf |
Marlin Dunham
New member
Username: Salchapete
Post Number: 3
Registered: 04-2007
Posted From: 131.39.248.7
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 19, 2007 - 06:18 pm: |
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Thanks Guys. It will be awhile before I can try it again. But I will print out the "Bible" and double check everything before I reinstall it. Right now, since I removed the engine to de-gas it I also decided to replace the stock chain tensioners and am waiting delivery of them. |
Sean McConnell
Intermediate Member
Username: Bookm
Post Number: 51
Registered: 09-2005
Posted From: 69.159.216.86
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 20, 2007 - 08:59 am: |
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While searching for help with my own carb woes, I came across these two sites that may be usefull. Now that I see how my Tillotson works, I can make the proper adjustments and hookups (after hours of frustration, LOL).
Tillotson Manual:
http://www.bethskartclub.com/onlineforms/Tillotson_carb_manual.pdf
Walbro Rebuild:
http://www.aerocorsair.com/id27.htm |
Marlin Dunham
New member
Username: Salchapete
Post Number: 4
Registered: 04-2007
Posted From: 209.112.151.121
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 26, 2007 - 02:39 am: |
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Still having carb problems The engine will start and run if you feather the throttle. If you stop so does the motor.
Carb has new gasket kit. None of the links provide helped as they don't discuss the WD carb. Or wouldn't open for me. Any suggestions out there? Maybe where to start with the adjustment screws? |
isaac eisenman
Junior Member
Username: Tropicjungleboy
Post Number: 12
Registered: 03-2005
Posted From: 201.224.139.175
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 26, 2007 - 08:24 am: |
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check for flotation needle adjust. baffle plate that support the needle against the diaphrag should remain "flat" with carb body. |
Mike Cummings
Intermediate Member
Username: Hydromike
Post Number: 70
Registered: 03-2005
Posted From: 141.149.254.227
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, June 26, 2007 - 11:26 am: |
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Marlin,
I'm assuming you have the non float-style Walbro WD carburetor on your 440? When you say you replaced the "gaskets" did this include all of the internal fuel pump diaphragms? If you did, and the pump is operating correctly, I'd start with the adjustment screws as you suggest. First, take them both all the way out to check for any signs of dirt or rust from the tank that can get through a filter (it happens). If you have two adjustment screws (the exact configuration of the WD series eludes me), a high speed and a low speed jet, turn them both all the way in until just finger tight. As a start, back both screws out about 1 to 1.5 turns. To get a good idle, only vary the low speed jet by turning it in or out in small increments. (Sorry, I don't know which one that is, front or rear.) You'll be able to tell which one that is, b/c the idle quality will vary as you turn in/ turn out. Nothing should happen to the idle quality when you adjust the high speed jet. Once you're satisfied with the low speed quality, you can do the same with the high speed jet. This one's a bit more tricky since you need to decide when it's running well at a high rpm, which means manipulating the throttle while reaching back over a whirring clutch and turning an itty bitty screw.
After you're happy with it, rip it off and put a float-style Walbro or a Mikuni on it. 
Good luck!
~m |
Marlin Dunham
New member
Username: Salchapete
Post Number: 5
Registered: 04-2007
Posted From: 131.39.248.7
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 29, 2007 - 03:48 pm: |
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I think replacement is the answer! You are correct, I have no float. Guess that is why I've been confused about the directions given before. Also there is a low screw, but just a hole where the high should be I guess. But there are 2 screws. One on the side of the carb (Says Low) and one on the top of the throat the is not marked. Guess it's all a moot point, I just have to find a mikuni that will fit that big orafice. |
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