Car fails to acheave high speed

Bill Goddard

Bill Goddard

Well-known member
A friend of mine recently complained that his new car (to him) was not able to go faster than 40 mph and was unable to climb grades very fast and barely made it to the top of steep grades. He changed everything: points, condensers, coil, sparkplugs. He checked the timing, compression (60-60-60-60). In the end, for lack of any other idea's I suggested he check the accelerator throw. He found that it was not allowing the throttle to open fully.
I guess this shows that we don't look outside of the box sometimes. We assumed it had to be timing or electrical. He even considered sending the engine out for overhaul to solve the problem.
Food for thought Bill G
 
On new to me car, one the first things I check (among others) is the throttle throw. Found a number of car that the throttle did not open fully.
 
I am right in the middle of that issue right now only my problem is at the other end of the scale. Car idles way to fast as the throttle will not shut all the way. Yes, the idle screw is backed off. Trying to think this through, if I bend the throttle control arm that is near the firewall so that the throttle will close it has an effect on fully opening the throttle. Does not seem to be a solution. Be very interested to hear some opinions. Bill
 
springerpete said:
I am right in the middle of that issue right now only my problem is at the other end of the scale. Car idles way to fast as the throttle will not shut all the way. Yes, the idle screw is backed off. Trying to think this through, if I bend the throttle control arm that is near the firewall so that the throttle will close it has an effect on fully opening the throttle. Does not seem to be a solution. Be very interested to hear some opinions. Bill
Click to expand...

Bill, When I first got my '30 Town Sedan it would not idle down and I found that my hand throttle was preventing it from returning to the idle position. I had to rotate the steering column a little to allow enough travel for the throttle to close all the way.
 
During my time staying at home due to Covid and looking for something to do, one of the things I have done is I rebuilt and installed a Marvel Schebler carburetor on my Town Sedan. And I ended up having throttle linkage issues as things were positioned a "little different" than the Zenith.

First thing I noticed is my hand throttle rod ends were worn out. Then I noticed the new repro hand throttle rod was ¼" shorter than the one that was on my car. (Surprise, surprise!!). Vendor catalog says 6" but it measures 5¾".

Anyway after fiddling around with it for awhile I finally decided to just make the hand throttle rod adjustable.

Maybe the OP could use something like this to get his throttle operating properly instead of bending things..

50564762166_884307c8de_w.jpg

 
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I will have to look into this accelerator throw thing. I've had this exact problem since the day I bought the car. Changed everything. I can get the 40 on a downgrade . . . sometimes.
 
Dann, There is a hard stop---no screw adjustment--- on the throttle against the carb. The accelerator rod should allow the throttle to touch the stop. Check that the hand throttle does too. Bill G
 
If the toe in is toed in too far it will cause wear on the front tires and reduce speed and power . I've had it happen . After the toe in was adjusted to 1/16 a person could feel the improvement .
 
Y-Blockhead...That's a neat new toy you have invented...I'll bet you could sell those things here on the site...or to a couple of the major suppliers...Ernie in Arizona
 
Ernie Vitucci said:
Y-Blockhead...That's a neat new toy you have invented...I'll bet you could sell those things here on the site...or to a couple of the major suppliers...Ernie in Arizona
Click to expand...

Ernie and Y-Blockhead, Nu-Rex makes a similar item intended for spark control rods. I don't see why it couldn't be used on throttle rods too.
 
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