1993 marathon 4 stroke...no top end speed

[BogeyBall]

I recently bought this old cart for a project. I was told it needed an ignition coil and that it hadn’t ran in years. I purchased a coil from Amazon and a carburetor from Amazon (yes cheap aftermarket parts) also put new plugs, air and fuel filters, cleaned the gas tank, changed the oil and a couple of other small things. So it runs! Yay! But the top end speed seems super slow to me. It has good take off power and uphill power but top end seems like maybe 6-7 mph. I think my riding mower would out run his thing. Any suggestions or help would be greatly appreciated! I haven’t messed with the governor or checked compression or anything like that yet, but I figure it has good compression with the take off power it has...

[JPonLKN]

Not enough info to be able to tell you what the problem is. If it is running well, spools up without issue, it could be a worn belt or defect in the clutches not allowing the clutches to expand and retract to their full positions, leaving you short of "High gear", or possibly your governor and throttle cables were adjusted to limit speed for some reason. It is possible the carb throttle plate isn't opening all the way, or there is junk in there restricting flow. (Yes, new carbs do come with junk in them, often).
As it isn't a cart you have any history with to understand what changed, I would say you need to take the valve cover off and adjust the valve lash to .004, remove the carb and clean it out very well, including removing the jets and cleaning passages, inspect the operation of the throttle cables and governor cable per the manual, inspect the drive belt for width 1-1/8" wide, and block it up, and run it to WOT watching the operation of the CVT (clutches) to make sure they both open and close properly. It is possible one or both are not operating for some reason. Take some photos of the throttle cable / governor set up, and clutches with belt on, and post them.

[BogeyBall]

Thank you for the input...I did adjust the valve lash but failed to mention that in my post. I will check the belt and take a few pics. Of the cables. Might be a day or 2 before I can check on all of it.

[crash12888]

Put the shift lever in the middle between forward and reverse.
With the seat off, start the cart and accelerate the engine using pedal, watch the drive (front) and driven (rear) clutches to see if they are cycling through the full travel motion, the belt should come pretty close to the top of the drive or front clutch.
If it doesn't then the engine RPMs are not high enough or the clutches need some attention, check them for grease fittings and give them only two shots.
If you are familiar with engines, you can tell if it is not revving up enough.

[BogeyBall]

So I played with the governor spring a little. Got it up from top speed of 9 mph to top speed of 15 mph according to a speedometer app I downloaded. Now my question is....how much can I tighten that spring/cable before it’s too much?? 15 is good but it was averaging like 12.

[JPonLKN]

Well, the 93 ignitor has the rev limiter, so the motor is electronically limited to not exceed the redline. The transaxle governor is a ground speed limiter for manufacturer insurance purposes. It comes down to how long you want it to last. They aren't made to run wide open at or near redline all the time, so you will likely shorten the life of the motor by doing that. I've gotten 20 mph out of several, but down hill, the rev limiter would drop ignition out periodically. Tighten it up till you start hitting the rev limiter, then loosen it up a little at at time till you no longer activate the rev limiter. It will only be a couple extra MPH though. You could go with larger tires and get a bit more out of it too. My experience with the three bolt steering column system is that it sucks...hard to get it to feel stable at higher speeds.

[CP241]

The 3 bolt steering always has a lot of slop. The bushing wears and really isn’t serviceable... at least not easily.

With stock tires around 18mph is about as mush as you’re gonna get out of it. But as JP said you will sacrifice engine wear running it like that for long. Set up at stock speeds that engine will pretty much last forever. Speed it up and it’ll handle it great. But, depending on how and how much you drive it, will probably start smoking in a year or two.

[BogeyBall]

I might try to tighten down the governor just a little bit more. It already smokes just a little when it’s first started...was worse before I changed the oil and cleaned the oil filter.
How big of a tire can I run on it at stock height? I read somewhere that those ezgo’s can fit a 20” tire, but wondering if y’all know for sure?