Toby -
In addition to the other stuff already mentioned, check the fuel flow.
If the fuel pump isn't up to snuff, or the filter is getting gooked up,
or the hoses are constricted, or..., the level of fuel in the float
bowls will drop at high RPM's making you go lean (more fuel being sucked
out than delivered).
If that's happening, Frank's choke trick may not be be conclusive.
Chris Kotting
ckotting@iwaynet.net
Toby Atwater wrote:
>
> Last week I decided that I would take my sprite to a mechanic (gasp!) to
> have him fit these rebuilt carbs I got off of EBAY (mistake #1) This was the
> very first time I have taken one of my own cars to a mechanic but since I
> have a good paying job now I figured I should try one out like everybody
> else does. I decided to go with this local British shop since they helped me
> out
> a few months ago and hooked me up with two witworth screws (idle adjust) for
> free.
> I drive up, between maybe a few dozen Xj6s all tightly parked on the
> left and right. I show him the rebuilt carbs and explain what I need.
> Basically I wanted him to tune them up and adjust them. (SU magic I call
> it). I wanted to let a pro tune them so I could watch and learn. I left the
> car there around noon and walked to class. Got back around one and he said
> he had centered the needles (the dashpots didn't click) and just finished
> installing them in the car.
> He insisted that the choke was necessary, and installed the dual choke
> linkage.
> (the old one was just set up to one carb). According to him you have to
> choke the carbs every time you start the car, If the choke isn't needed it
> means the carbs are running rich all the time. Is there any truth to this? I
> thought the choke was only usually needed for cold morning start ups when
> the fuel won't atomize well.
>
> Anyway he starts tuning em and using his stethoscope and vacuum tool (to
> balance the carbs I think) and he gets the idle spot on at 1100 rpm. he then
> adjusts the mix and does his thing. I learned allot and I think I could do
> it again....
>
> I then pay an exorbant amount of money ($155) and take off with my Sprite.
> Well at least try to take off. Complete loss of top end power. So much loss
> of power that it wont even redline in 2nd or 3rd... wasn't even able to pass
> 4th. I went limping home broke and depressed. Obviously something is up.
> Either the mechanic wasn't up to stuff, or the carbs aren't up to specs. But
> it purrs at idle and low throttle. Really runs smooth. Also starts much
> easier.
>
> Here are my theories.
>
> 1) The accelerator pedal feels different. He said he had to adjust it to get
> some slack in the cable to bring the idle down. Could the pedal be touching
> the floor before it opens the butterflies %100 percent?
>
> 2) The needles in the carbs... I just e-mailed the rebuilder of the carbs to
> see
> what needles were in there. Maybe some kind of strange really lean top end
> needle or something wacky.
>
> Any other theories? ideas? etc??
>
> Thanks
>
> Toby
> 69 Austin Healey Sprite
> 71 FJ40 Toyota Land Cruiser
|