New Weber, a bit of binding?, mileage info

[trevmountain]

Hello yall, the new weber has been doing great. I've done three tanks of mileage checks and it seems to get about 31 mpg as an average. I am pleased with this because with my stock carb I was getting at best 28. The only problem I've encountered is and it's only been this past week or so that it's done this, when cruising and if I come to a stop and shift into neutral the rpms race up but if I tap the gas pedal it comes right down to normal Idle. This happens any time I come out of gear from an accelerate or deccelerate. I figured it was just binding in the linkage so I 've adjusted just about everything I possibly can. I've adjusted alighnment of the throttle bracket to be in perfect elevation and alignment. I've messed with the throttle cable tension. I've adjusted the throttle shaft nut multiple times, tight, just a little beyond finger tight, finger tight, and loose and nothing seems to help. I had the idle mixture perfect and it ran fine for a week or so and then all the sudden it started doing this, I'm baffled and need some advice.

Trevor

[ARCHINSTL]

Don't take offense, but you did not mention this - have you lubed the cable from the pedal to the bracket?
While I was not having a similar problem a couple of years ago, I did this out of habit from the bike shop, and found that the "pedal moved" more smoothly.
I used White Lightning, which is a Teflon lube common in bicycle stores, but I'd imagine any light lube would work OK.
I removed the cable from the bracket , elevated it, and dribbled the lube through until it exited the casing at the pedal (protecting the carpet with a rag).
And - did you check that the "loose" pedal moved freely by itself? Something could be binding there.
Tom M.

[takza]

With the OEM carb...I removed the throttle spring and took the rubber tube out from inside it...replaced it with a similar sized spring and hooked both up to the original mounts...adds some strength and helps bring it down to idle better. Plus WD40 the cable now and then.

[sdoan]

It's probably the throttle cable. Make sure there is a little slack in the cable when the throttle is fully closed on a hot engine.

One other thing can cause the symptoms you describe, but I shouldn't be happening on a new carb. Carbs with poor alignment of the throttle plates in the bore will stick against the side of the bore holding the throttle open slightly. Two causes: The throttle plates are loose or misaligned on the throttle shaft. Or the throttle shafts are worn allowing the whole shaft to be out of alignment (common on old SU carbs).

To check the throttle plates you need to remove the carb, but it is absolutely the last thing to check.

[splatterdog]

If everything is free, add a little more return spring tension.

To calculate you carb's estimated savings- Annual mileage divided by MPG times average cost per gal.

I did the math on your 3mpg gain. 15,000 miles per year would yield a $208 savings at $4 per gal. If you go 25,000 or more like my wife, the kit will be paid for in a year or less. The 84 gained an impressive 8 mpg and the kit paid for itself in less than a year, back in the good old days of low $2's per gal. This year it will save over a grand.

Better running engines last longer too...

[keith]

I had the same problem so I added the spring that came with the kit.



I drilled a hole in the original throttle cable bracket. We used the spring from the throttle kit. BTW, the installation instructions did not address this either, didn't even show it. I could have used the spring off the old carburetor, but it is very stiff and didn't look as good.

[trevmountain]

Wow thanks guys, it's so nice to have a site like this to get info. I will try some of these tips and get back with yall. Thanks again