rjr 0 #1 Posted October 18, 2011 I have an early 90's toro weedwacker with very few hours. I rebuilt the Walbro WT400 carb. Now it starts on the first pull but quits within seconds. If you open the choke one notch it screams for a second then dies. I messed with the high and low speed needles but other than not starting at all it didn't change things. I am thinking that the needle height isn't correct, but before I take it apart again I thought I would ask for a second opinion. Share this post Link to post Share on other sites
Horse Fanatic 51 #2 Posted October 18, 2011 Well it's not getting fuel. Did you completely dissasemble it and soak it in carb cleaner? How many turns out do you have the jets? Share this post Link to post Share on other sites
wh-jason 33 #3 Posted October 18, 2011 Can you see fuel flowing thru the primer bulb when it's running? If not you may need to seal the welch plugs in the carb. I use fingernail polish it works great. Share this post Link to post Share on other sites
rjr 0 #4 Posted October 18, 2011 disassembled, an hour in an ultrasonic cleaner, 20 min in clean water, a few minutes in alcohol (I own a manufacturing business, I don't know how the rest of you guys do it). Replace gaskets, needle, etc. I started with both out 1 1/2 turns. opened up 1/4 turn, then another 1/4 turn. then tried 1 1/4, and 1 turn. At one turn it wouldn't start. I am also considering that there is a leak in one of the fuel lines. They are new. I rerouted a coupe of them around the back of the carb Share this post Link to post Share on other sites
rjr 0 #5 Posted October 18, 2011 yes, you can see fuel in the bulb but there are a lot of bubbles. Share this post Link to post Share on other sites
sgtsampay 117 #6 Posted October 18, 2011 Wouldn't it getting airbubbles inthe fuel line, mean that its sucking to much air from the gas tank somehow? Share this post Link to post Share on other sites
Don1977 605 #7 Posted October 19, 2011 If the fuel tank is full there isn't anyway to suck air from there. There could be a hole in the line above the tank or the line isn't fitting tight enough on the carb. Share this post Link to post Share on other sites
Horse Fanatic 51 #8 Posted October 19, 2011 A leak in the fuel line would do it, but if they are new that would be unlikely unless they were damaged. Did you use Tygon? Is the carb gasket positioned properly so that the little hole for the vacuum port lines up with the hole in the gasket? If so, you can also try and blow that hole out, it's not likely to be blocked, but if it were, it wouldn't pump fuel. If all else fails, take the muffler off and look at the piston. If it's scored, even if you have compression, sometimes it just won't run. Share this post Link to post Share on other sites