Help with 2005 EZGO Downhill Jerking

[jlsanger]

Hi all,

I am brand new to this forum and I am in need of help. I recently bought a used 2005 ezgo txt, it has the Robin 295cc motor. I have done a complete service on in, installed a new carb, new drive belt, and cleaned both clutches to the best of my ability.

Here is my problem:

I start the cart up, and it runs like a dream. I can easily climb hills with no issues, and I have the governor turned in so that I have a nice cruising speed of 18mph (I'm using this cart as a run around town rig since I live in a small town).

Now to the fun part- when I start to decent a hill, the cart starts jerking or "bucking" intermittently. On some occasions, it will continue to jerk slightly when I accelerate on level ground after exiting the hill. After I come to a complete stop, I start up again and everything is fine, smooth acceleration, hill climbing is great, and then I approach another downhill then it repeats. I have done the neutral test with the motor shut off and coasted down the hill smoothly, no jerking or bucking.

What in the world is going on with the cart? Clutches? Rear differential slipping? Micro switch intermittently failing? I've even had the back cover off the cart while driving it so my dad can at least observe the driven clutch when going downhill, he said that it's spinning and doesn't seem out of the ordinary. Is there a diagnostic test that I haven't done yet?

I am truly at a loss, help!

[trig123]

Are you letting off the gas pedal going down the hill

[jlsanger]

Yes, when I let off and let it coast. The best way to describe it is like imagining that someone or something grabs on to the cart from behind like they want to stop it but suddenly lets go.

[Cartmaster]

you need to drive it downhill with your foot on the gas pedal. Do not let it coast at low revs as the drive belt will disengage from the clutches when the engine rpm's drop and can allow the cart to get out of control. Its probably the belt grabbing at the clutches that is causing your problem.

[jlsanger]

Okay I will try that and let you all know.

[jlsanger]

I tried that, accelerator all the way down. First time downhill no jerking at all, tried another hill and same thing. Then went back to first hill and there was slight jerking, even with accelerator all the way down. I did replace the belt yesterday and put a 1 inch shorter belt on it for more low end. The cart accelerates to speed very smoothly and I can maintain 18mph cruise speed, which is what I want. It's just the downhill jerk that is driving me crazy!

[trig123]

I would jack the rear up and put jack stands under it for safety. Run it up and see what happens. I am thinking one of your clutches is not working correct but that is only a guess.

Maybe the engine is hitting the Rev Limiter and causing this issue because of the driven clutch being bad .
Again I am only guessing.

I have seen one being bad. This cart would not open up on flat ground and hit the Rev Limiter, a little jumping or bulking as it would hit the Rev Limiter and shut the engine off and then back on again. I never tried it downhill . The best I remember the driven clutch was stuck . I think this engine is designed to shut off when it hits around 3700 rpm's.

A warning on messing with things. You tighten up that governor spring too much and you ask for problems later down the road. These engines were not designed for high speeds. In no time your intake valves will sink in the head. Heating up is not good and thats what happens when you run them about factory setting. 12-14 mph is how they came from the factory. Just my 2-cents on this . Its your cart.

Hard to tell without seeing exactly what is happening without seeing what it is doing.

Is this cart lifted ? with larger than stock tires ?

Cartmaster should be here soon and maybe he can share more information than I have. I think his time zone is like 6 or 7 hours ahead of my area. Good luck

[jlsanger]

Cart is not lifted, stock wheels and tires. I don't have the governor spring turned in all the way but I can back it off some more from where I have it (I'd say about 1 1/2" in from the end of the threaded shaft. I put a piece of rubber hose over the shaft for easy adjusting. The governor still engages fine.

I am also thinking it is the drive clutch. I've had the driven clutch off and did the spring test where you turn both sides opposite of each other and it snapped back like it should (saw this on a YouTube video). I've also had the rear jacked up and have watched the clutches engage, they both seem to be working normally. But that was in a jacked up situation.

My next guess is to pull the drive clutch and take a look - trouble is - what should I be looking for?

[Cartmaster]

Ok, so its jerking with both of the belts that have been on it. Were both of these belts brand new when fitted and the problem started at the same time? Do you still have an old belt to try back on there to see if the issue stops? Just trying to eliminate the belts being the issue. then we can look at clutches. The only time i have seen this happen when "driving" down a hill was with a cheap brand belt that had a deformity and was grabbing at the clutches.

Just had a thought. When the cart is jerking, is your foot completely off the gas pedal, or are you feathering it lightly, If so, it may be causing the revs to drop enough for the belt to disengage from the clutches, then touching the gas pedal a tad, will spin the motor and re engage the belt and feel like someone holding you back. If you keep your foot off the gas the engine will stop and disengage the belt allowing the cart to freewheel and speed up! then you hit the gas again and the belt engages and feels like being held back again?

Just trying to think of anything obvious before pulling stuff apart.

If you did your test again, watching the clutches going down hill, concentrate more on what the belt is doing rather than the clutches! it might give us a bit more to work on. It may just be that the belt needs more time to soften up, hence trying an old belt again to see what happens.

If all seems good with the belts, then maybe something is causing the drive clutch to grab and release the belt intermitently. If its a clutch problem, its most likely to be the drive clutch over the driven clutch as the drive clutch action controls what the driven clutch does.

[jlsanger]

It's been doing it with the old drive belt as well as the new one that I just installed. It will jerk with my foot down on the accelerator, feathering it, or even letting off completely. The new belt I put on is an ezgo OEM replacement. The old one was an ezgo belt. Only difference is that the new one is a little shorter than the other - I've read on other threads here that it can make a difference in low end and acceleration, which I have noticed. I think that the belt is working fine in that regard.

I would appear that the issue lies in the drive clutch - from what you have told me and from what I have researched.

Thank you for your advice so far and I would appreciate any more you have!