There’s currently a thread about throttle bushings, those can mess with throttle linkage binding, they almost always need replacing if they have never before.
Be sure to watch the attached video. It makes it uber clear how to check for the problem and what to do about it.
I’ve had a look at the bushings - well, I would have done had they been there! John_john has been messaged.
Whilst looking at the throttle linkage (not moved since I shut down the engine post last run with idle sitting at 1200 rpm, I noticed that the ‘arm’ (for want of a better term) wasn’t sitting back against the stop screws hence the butterflies must have been open.
getting those two throttle arms dialed in is important. I’ll usually pop them off while it’s idling, and then reattach one at a time to make sure idle doesn’t go up at all, meaning they’d be too long.
On the flip side, if they’re too short, the throttle response will be sluggish, and the TPS will tell the ECU to give more fuel, yet the throttles won’t be open yet.
And getting them both identical is important, you don’t want one bank opening before the other, engine will stutter when giving it some gas.
Hah!
You don’t really need John_john for a couple of simple bushings, although his sets are very nice indeed. You can buy bushings with the required ID and OD (5/16" and 1/2" I think, double check before buying), cut to the length needed with a hacksaw. You could put a C-clip groove in it by chucking it up in a drill using a 5/16" bolt and nut and then holding a hacksaw or Dremel with a cutoff wheel in it against it as it spins. There is no need for the flange on the back side of the bushing.
Or you could contact this guy:
JohnJohn makes quality parts. But I replaced mine before he started making the bushings, some posts a few years ago about buying bronze bushings. I found some online for like $10, easy to install, no C clips needed. Work great.
yeah, one of my original bushings was in pretty bad shape, the other one was actually OK. Explained why my throttle response felt funny.
Hi All
This will be the last input for, hopefully, some time as she is running beautifully.
If you all recall, after removal and cleaning out the sump tank, and replacing the fuel pump, the problem with lack of power/hesitancy/no power under acceleration was solved.
The remaining fault was an idle sticking at around 1500 RPM. The throttle linkage bushes have been replaced with JohnJohn’s. It seems that the remnants of the original bushes (missing on the port side, half missing on the starboard side) was causing the throttle to jam slightly open. Everything in the throttle system is secure again and the throttle response is much more precise.
That’s all for now - until the next crisis!
I have pondered a couple of things I’d like to fit with ball or roller bearings for essentially frictionless movement and zero hysteresis. One was a mechanical advance mechanism – but those are done electronically these days, so that concern has gone away. Another was a throttle linkage, every pivot from the pedal to the butterfly. I kinda wonder whether that would be wonderful or awful. It might be awful, in that the pedal wouldn’t stay still under your foot, just the weight of your foot might gradually push it down. You might have to jam your foot into the carpet to hold a steady speed.
Now that one’s pretty well gone, too. Modern engines have a potentiometer for a gas pedal.