John deere 400

tmartin · Post by **tmartin** » Tue Jan 13, 2009 2:46 pm

I have posted this before recently without much response. I have a 73 400 jd with a 340 ccw in it with the original walbro wda 32 carb. I rebuilt the engine and carb. I ran awhile with no trouble. Recently i warmed up good and parked it for maybe 10 minutes. It would not start when I came back to it. It flooded itself bad. I took the carb apart again and replaced the check valve and tried to seal it up better by honing the plates. It still acts up like before though. Last night after i warmed it up it would not start with the light switch on. It would just spit and sputter. When I noticed the switch was on i shut the switch off and it fired up. Do I have an ignition problem or voltage regulator problem? What do you guys think.? Or was it just a fluke that it started right after turning the light switch off?

Rodimus Prime · Post by **Rodimus Prime** » Tue Jan 13, 2009 3:35 pm

lighting coil is completely seperate from ignition system of snowmobiles.

There is a line that runs from carb to bottom of engine. This is the Impulse line, it should never have fuel in it. If your sled is "flooding" chances are you will see fuel in that line when engine isnt running leak from carb to engine.

At moment i cant remember what is usually overlooked and causes this . i know it was something simple just cant for life of me remember. ON a non rebuilt carb it would be bad diaphram. During normal running its not a problem its only when sitting the fuel goes to engine instead of back to tank.. Gaaa if i remember ill post.

tmartin · Post by **tmartin** » Tue Jan 13, 2009 3:44 pm

Thanks and i hope you can remember because this thing is giving me a lot of grief although i am getting good at disassembling it.

Rodimus Prime · Post by **Rodimus Prime** » Tue Jan 13, 2009 8:43 pm

Did you keep the original gaskets/reedvalves? Try , with carb empty of fuel of course, plugging return line blowing on inlet line with your mouth ( if you have a popit gauge its nice but not nessary) impulse line should have no air coming out of it. Im trying to remember, the flat side of one plate should have i beleive 3 holes which are covered by a rubber set of reed valves from gasket kit some kits have a fiber type reed gasket but not the rubber one. the fiber wont seal properly. Opposite of those holes is 3 important little springs that usually go missing. If memory serves also on that plate is a rubber check valve that in some kits is more of a hard plastic and leaks as well. visual inspection of the checkvalve will see if its good it should completely seal all around at rest with no small lifts in one corner. Hmm still not sure if i got it but those are things i check when doing them right now.

I

tmartin · Post by **tmartin** » Tue Jan 13, 2009 11:41 pm

I do not have the original parts anymore. They were shot. I do know that the springs are all intact. I will try this. Thanks.

DLDeere · Post by **DLDeere** » Mon Jan 19, 2009 10:41 pm

I have this same problem on my 400. I opened the drain plugs at the bottom of the crankcase and fuel ran out. I went through the carb again and adjusted the metering lever so it wasn't as high. That seemed to help, but is still a problem. It will be running fine, then when I shut it off, it won't restart. It acts and sounds like it's flooded, but the plugs are dry. Good spark on both plugs. Cranking enough without using the choke and without touching the throttle will finally get it started again. Very odd!