Walbro WDA-1

ejazz · Post by **ejazz** » Wed Dec 31, 2008 1:35 pm

Hey guys,
I pulled the '74 300 back out of storage and got it running again for this year. Last year I was having trouble starting it after it was warm and figured it was the fuel pump on the WDA-1. I purchased a nice rebuild kit online and started disassembling the carb and putting the kit in.
My question is this. If you go to JDsleds.com and look at the diagram of the Walbro carb in the TECH section, my carb does not have parts # 33 and 34. My kit came with a new fuel pump spring (33) but not the three valve springs (34). My carb doesn't look like it was messed with before so I do not think someone left these parts out. Do I need them or is the diagram a different variation of what I have? The engine is the 300 Kohler. Thanks, Eric

ejazz · Post by **ejazz** » Tue Jan 06, 2009 1:13 am

Anyone home?

Is the WDA-1 even the right carb for this sled. The WDA-1 is stamped on top of the flange where it bolts to the motor.

400brian · Post by **400brian** » Tue Jan 06, 2009 4:23 am

According to SM2100, the carb used on '74 and '75 300s was the WDB-31

I tend to think the parts mentioned are required. The manual makes no distinction between the carb models in the exploded view.

Post by **Matt** » Tue Jan 06, 2009 10:00 am

I don't know much about the WDA-1, except it seems to be the only Walbro that has it's very own rebuild kit listed by the suppliers, and does not use the standard kit. There may be some differences, but I don't know what they are.

ejazz · Post by **ejazz** » Tue Jan 06, 2009 10:07 am

Thanks Brian. It makes sense that I would need those parts. The sled wil not start after it gets cold. I carry a can of carb cleaner with the red straw attached and give it one squirt through the hole in the top of the carb when it sits and it starts right up.
I replaced all the fuel lines including the impulse line and put hose clamps on them. Installed an inline primer bulb and rebuit the carb. The sled has great compression and once it starts the thing idles and runs great. Once it cools down though, I can pull on it twenty times with the choke on and it won't even burp. Give it a shot of carb cleaner and it starts right up. Kind of embarrasing to pull the cowl cover off everytime in cools down. Anyone have a WDB-31 laying around?

big danno 1970 · Post by **big danno 1970** » Tue Jan 06, 2009 12:23 pm

Hole in the top of the carb? should be no hole in the top of the carb that is open,can you post a pic?

ejazz · Post by **ejazz** » Tue Jan 06, 2009 1:34 pm

I am sorry. Not in the top of the carb but in the hole in the spacer block for the air box. WDA-1 is stamped in the flange but other pictures I have seen of the WDA-1 show it being a smaller carb. Could I have someting different?

Attachments:

SDC10367.jpg (1.76 MB)

S_Kyle · Post by **S_Kyle** » Tue Jan 06, 2009 2:33 pm

Looks like a primer should be attached there. Hook one up and you should be able to get rid of the carb cleaner.

JDT · Post by **JDT** » Tue Jan 06, 2009 6:04 pm

WDA-1 was a carb used on early 70's Cats.

big danno 1970 · Post by **big danno 1970** » Wed Jan 07, 2009 12:34 am

Do you run the sled with the primer spigot open?If so plug that up,that is a darn good air leak which is bad.
When is the last time the crank seals were replaced? This could cause the hard start as well as they might be on there way out.

400brian · Post by **400brian** » Wed Jan 07, 2009 3:50 am

ejazz

If it ran before with the mentioned parts missing, then they probably shouldn't be in there.

If Deere never used the WDA-1, then that would explain why the service manual might not show any differences between carbs.

Putting a primer on it might solve the starting issue. Is that the only problem?
You could always try the correct carb, but you could have any number of issues.
Is the fuel running back to the tank? If so, you may have a bad check valve in the pick-up.

JDT · Post by **JDT** » Wed Jan 07, 2009 7:11 am

I see in the picture that there is a Cat part number stamped right on the flange.

Not many Cats had primers. The barb is there but it more than likely is not drilled out.

ejazz · Post by **ejazz** » Wed Jan 07, 2009 11:52 am

I have not changed the crank seals and do not know if they ever were. If the crank seals were bad, would it run as good as it does. I have had this same problem with the sled since I have owned it (7 years). Last year I put on at least fifty miles and the sled runs great and idles well. The plugs are not the light brown color I would like but I do run it a little rich.
There is a number stamped on the flange that is not a John Deere # so this probably doesn't belong on this motor. I am trying to locate a WDA-31 to try the correct carb. I may even get a little more power out of 300.
I don't know if the hole in the spacer block would cause an air leak while trying to start it because usually I have the choke butterfly closed and the hole is to the airbox side of the carb.
I have an inline fuel bulb with a check valve in it that prevents the fuel from draining back to the tank. There is also a clear fuel filter between the tank and bulb and it is always full of fuel. The bulb remains hard (pumped up) on the sled.
Putting a primer on it would solve the problem but so would the correct carb. -Eric

DLDeere · Post by **DLDeere** » Wed Jan 07, 2009 2:54 pm

There are some carbs for sale in the Classifieds forum. Here is the link. http://s12.zetaboards.com/jdsleds/topic/5015800/1/

If there is a lot of oil around the base of the engine and the motor mounts, that is a good indicator that you need new crank seals. Check for that. If it's clean and dry, then your crank seals are probably OK.

JDT · Post by **JDT** » Wed Jan 07, 2009 5:50 pm

You probably would have never been able to put 50 miles on it with bad seals.