Walbro carb

[jep_800]

I know this has been discussed in past threads. Looked at a lot of posts, and even found a very good tutorial on Vintagesleds.com. Everyone says that when you put the metering lever in, it must be adjusted lower to compensate for the difference in the new meter button. It also says to bend your tabs at the needle or fork end. I've cleaned my carb from the JDX8, and installed all new Winderosa set of diaphrams. I adjusted the forks down so that it is just flush with the body or slightly lower. My question is: What about the lift of the needle? when I adjust it that low, it appears that the needle doesn't move, or barely move. Is that what it's supposed to do, or how do I compensate so the needle will rise, but the lever arm is below the carb body? Isn't making sense to me right now.

jep_800.

[jep_800]

I have the Walbro off my 800 (same as the X8), and opened it up to see how I set that metering arm. Since rebuilding that carb when I restored it, I've never had the fuel pouring out of the throat like some have said about rebuilding these carbs if you set the lever wrong. So, it appears that it is almost flush with the carb body (just slightly above), and it also barely moves the needle when depressed. This is exactly the way I set the metering arm off the X8, so should work the same. Time will tell.

[BlazinC5]

So, did you ever get your carb figured out fully? I'm currently going through some trial and error with mine from the X8. I did the winderosa kit and found I had ALOT of excess fuel flowing through the carb. So much so that it wasn't burning the oil and made a black sludge mess. Didn't understand the metering lever stuff yet at that point. When I read up more, I adjusted the lever to where it was more in line with .005". It seamed better but still alot of smoke and hesitation. So this last time I adjusted the lever to barely touch a straight edge. I also double checked all the ports on the body and made sure nothing was plugged from the new gaskets. Seams to be better yet again. But that pesky hesitation is still there. I gotta pick the rpms up for it to clear up and plugs are still coming out wet. It does idle fairly well but loads up. Looks like I will now adjust the lever lower yet, to below the body. If I adjust the idle screw down on the engine, it don't want to pick up if I give it throttle. But it won't die either. So I must be on the right track. The impulse line as far as I can tell is dry and the vapor/return line is full but does kick bubbles back to the tank.
Did you by chance experience any of the issues I described? I'm not sure what I'm missing yet. But I'm still trying. All I can come up with is that it has to be that dang lever adjustment.

[jep_800]

Devin,

All I've done so far is had the machine at idle since rebuilding it. Mine does smoke a little blue, but I also mix at 40:1, and made sure I had oil at start up so I didn't damage anything. So far, I do not experience any hesitation when I hit the throttle, but I also need to wind her up to full to see what it's like in the power band. I plan on tuning based on my Walbro sheets that I've saved for a few years.

Now, since my 800 has the same Winderosa set, and I've adjusted that lever to just barely above the carb body, I did not notice a lag or extra fuel in that engine. I did a fairly long run last winter with it, and the power seemed to be good. No hesitations anywhere. I had other problems, as it leaned out, cause I think I had an air leak at my carb flange, but that's another story. So, now that I think it is correct, I will have to try both the 800 and X8 to see if I need to adjust those carbs further. A lot of guys are not fans of Walbro, but I think if they are tuned right, they operate well. I like the machines to be original, so that's why I've kept these carbs instead of changing out to Mikuni.

Jason

[jep_800]

I put the X8 up on stands this weekend in order to check my track alignment and clutch engagement. I pulled the 102c which I found on the sled, and installed a rebuilt 100c with new weights, rollers, bushings, etc. It seemed to engage nicely with F2 weights, but I think just slightly heavier would also help. I should remove the secondary and install the NOS red spring that I've had on my shelf for a while. Might help with my backshift.

Anyway, the carb does need a little tuning in the power band, so once we finally get some snow here, I need to do a few test runs and start some adjustments. This engine seems really solid, so will be nice to get the fuel/air fine tuned for operating.

[400brian]

The metering lever is very important, you are on the right track there. The other possibility you might consider is the needle and seat. You can polish up the seat with a wooden golf tee, also Pats Small Engine, and Parts Reloaded, still sells the needles. Just a thought.

[farleyjd400]

I found a really good step by step procedure for these carbs with detailed picture i can send you through email. i just rebuilt a Walbro carb (WRA-31) on my 73 JD400 and it runs great. here is what it says for the lever adjustment.

: Check inlet lever height. Use a feeler gauge to set the highest point on the inlet leverl 0.005" - 0.020" above the gasket surface of the throttle body. In a pinch, you can use a spare choke butterfly**** to set the the inlet lever height. Choke butterflies are 0.020" thick and are essentially a "go-gage" for checking the inlet lever height. When sliding the butterfly across the gasket surface from the side, If the tab of the inlet lever contact the butterfly, it's a "go". If it doesn't, it's a "no-go" and needs to be adjusted. Adjustment should be made at the fork of the inlet lever and not at the base of the curved portion to prevent fatiguing.

[jep_800]

Andy, I followed the same rebuild steps/explanation you just quoted. I know Brian is right, as he's rebuilt a bunch of these Walbros about that metering arm. I did use a feeler gauge to check the height of that arm above the carb body. Both of my WRA-31's are set the same, and they do seem to operate very well. It is definitely not set at the factory height, and that is due to the Walbro rebuild kit metering diaphragm is different than the original. That center button height must be different than how they came.

If I do have any further issues with fuel metering I will look next to the needle and seat. That is good to know that Pat's small engine may still supply those needles. I do use them from time to time for parts.