Gas Precedent jerky start

[Kyleh1]

Hi all. I searched the forum but couldn't find an existing thread on this. I have a 2007 gas Precedent with a minor but annoying issue. When first starting off, it starts fine and is nice and slow when barely giving the pedal any gas, just like it should. Once I give it full throttle, it accelerates fine and achieves full speed. However, after slowing back down, it won't go as slowly as it did before. Instead, when the pedal is barely pressed, I get medium speed, and not the slow speed that I should. To go slower you have to let off the pedal completely. As a result, you get a jerky on then off pattern. To me it seems like a sheave issue and that they're not returning to the original positions. I understand the principle but am not sure what's the best way to test and isolate the issue. Does anyone have an idea? I''d appreciate it.

Thanks,
Kyle

[Fairtax4me]

The primary clutch may be sticking closed and is dragging on the belt while you're trying to start off.

Basically when the engine stops turning the primary clutch should open and totally disengage from the belt. There should be a small gap on either side of the belt and it should roll freely on the clutch.
If the sheaves of the clutch are still pressed against the belt, the clutch isn't releasing all the way, and can give you those jerky starts.
Sometimes blasting out the clutch with compressed air can get it working again temporarily, but it will need to be removed and rebuilt to be fixed properly.


The secondary clutch can also cause a problem like this if the clutch is not closing properly. It leaves slack in the belt which causes it to skip on the clutches.
Again, compressed air can sometimes get it working temporarily, but if its sticking it usually needs to be rebuilt.

[Kyleh1]

Thanks for the reply. I understand the primary but don't understand the secondary. If the secondary was gapped and not closing properly, wouldn't that result in a sluggish start? Instead, I have a overly fast start.

On the primary, I'm thinking that I can recreate the issue in neutral and revving the motor. Any reason that you can think of that this wouldn't work?

I'm hoping to get out to the cabin soon and try this out.

Thanks,
Kyle

[Fairtax4me]

Yes, put the cart in maintenance mode and check to see how the clutches respond. They should move smoothly.

If the secondary clutch doesn't close all the way it leaves slack in the belt, and also causes the belt to sit lower between the sheaves which gives a lower effective ratio. The lower the belt is in the secondary, the faster the cart goes.