One of the most common issues with a clutch is that it is always engaged and trying to spin the rear wheels.
As soon as that engine fires up the go kart takes off when started!
I’ve been there my little Manco go kart that I purchased for a fun yard kart would not stay running. As soon as you pulled the starter the engine would fire up but, almost immediately a grinding sound would occur, and the engine would stall out.
I raised the rear wheel off the ground and found that the clutch was engaging!
My Solution? I purchased a new clutch!
The Cost of a centrifugal clutch these days is not worth your time to disassemble, replace parts and then reassemble.
At Better Karting we are here to help you maximize your go karting fun. If you like to take things apart like me to learn, then by all means tear that puppy apart!
My Go Kart Clutch is Always Engaged
- Bushing/Bearing needs Lubricated
- Clutch Spring is Broken
- Bushing/Bearing is Worn
- Engine Idle is out of adjustment
- Chain or Belt is Too Tight
This is a really common issue. When the go kart engine is started the rear axle is trying to spin. If you are lucky the engine stalls out and if your unlucky the go kart takes off and you are chasing it
1. Clutch Bushing/Bearing Needs Lubricated
When you have a go kart takes off when started
The first thing you should do is lubricate the bushing or bearing.
This is the easiest procedure and could save you money and work!
Lubricating your clutch bushing is super easy also.
You want to watch out for a couple things though.
More is not always better – All you need is a few drops on the bushing. If you overload on the lube then you might contaminate the shoes, drum and spring. Resulting in your clutch slipping and overheating.
Only Spray the Bushing – When lubricating the clutch bushing only spray the area between the snap ring and drive gear to avoid clutch slipping issues.
2. Clutch Spring is Broken
This is the clutch spring out of one of my centrifugal clutches. They are really simple. They hook together at the end.
The clutch spring can break at any point but the weakest point are the hooks at the ends. A go kart clutch is subject to a lot of heat, friction and constant motion. All moving parts breakdown.
The clutch spring holds the shoes away from the drum. If the spring is broken or weak the shoes will engage with the drum and start to drive the rear axle.
How to Fix it – My Go Kart Clutch is Always Engaged
- Purchase a new clutch
- Replace the spring
Honestly, just buy a new go kart clutch.
If the spring broke, more than likely you are going to have worn shoes, drum and heat damage. The cost of individual parts will far exceed the cost of a new clutch.
3. Bushing/Bearing is Worn
The clutch body is splined to the engine. The clutch drum is connected to the rear axle via the chain.
The drum is stationary when the go kart is not moving. The clutch body is spinning at engine RPM.
With all surfaces in contact there needs to be a bearing or bushing to prevent seizure.
If a centrifugal clutch bushing is worn it will create fiction and cause the clutch drum to want to spin with the body.
This is exactly the situation I had with my clutch. The bushing was in terrible shape. I could have just lubricated it but it was too far gone.
The process is pretty easy to replace a bushing.
4 Steps to Replace a Clutch Bushing
**Take note of the depth of the bushing install and be sure to install the new bushing to the same depth!
Step 1: Remove the Clutch from the engine
Step 2: Remove the clutch drum by removing the outer snap ring
Step 3: Find a piece of scrap metal that is the same diameter as the bushing. Try to find a piece that is as flat as possible.
Step 4: Fit the new bushing to the clutch and press it back in
**You can put the new bushing in the freezer for a coupler of hours. This will actually shrink the bushing by a couple thousandths of an inch allowing a much easier press fit!
**You can also put the clutch drum in the oven at 250 F for about 30 minutes and that will actually make the bushing bore larger by a couple of thousandths, making a much easier press fit! – BE SURE TO WEAR GLOVES!
4. Engine Idle is Out of Adjustment
An engine idling too high will cause the clutch to engage. Lower the engine RPM and see if the issue is resolved.
**This is the last adjustment on this list because anytime you mess with a carburetor you need to take care. Always remember how many turns you adjusted so you can go back to the settings you started at.
This one is a bit trickier but can certainly cause a go kart to always take off when started.
A centrifugal clutch is designed to engage shoe to drum contact at a certain rotational speed.
As the clutch is spinning around as the engine is running the shoes are kept away from the drum by the spring.
As engine speed increases RPM the spring can only hold the shoes back for so long. Thus, you have the engagement RPM. The centrifugal force of the rotating weights want to fly outward toward the drum.
For your common go kart engine, like a predator 212, right around 2500 RPM is the spot where a clutch should engage.
The engine idle speed on a Predator 212 engine is anywhere from 1600-1800 RPM. So, it is fairly close to clutch engagement speed. If you have an issue with your engine and the engine speed has increased at an idle then your clutch may want to engage.
Adjusting idle speed may be difficult because you may not have any way of knowing what your engine speed is. If you have a tachometer installed, you would know but otherwise it is all a guessing game.
Adjusting Idle Speed on a Go Kart Engine
Step 1: Ensure your have clean fuel in the engine
Step 2: Verify the air filter is in good condition and not dirty, restricting airflow. If in question, clean around the carburetor and remove it for this test.
Step 3: Locate the idle adjustment screw and rotate counterclockwise to lower the engine speed.
5. Chain/Belt is Too Tight
Just like Goldilocks the tension on your go kart chain has to be justttttt right.
Too tight and the chain will want to bind up the clutch and you will result in the go kart taking off once the engine is started.
But, too loose you risk jumping the chain and excessive wear on the inks.
Check the tension of the chain and adjust the movement of it so you have about 3/8 – 3/4 of an inch.
The center housing or drum needs to float on the bushing while the clutch is not engage. A chain that is too tight will pull on the clutch drum and put pressure on the clutch bushing. This causes friction and viola the clutch will start to turn the rear wheels once the engine is started.
So, what do you do?!
First, if your engine is on slotted motor mounts, slide your engine toward the rear gear creating some movement in the chain. About 3/8 – 3/4 of an inch.
If you cannot move your engine look at the mounting of the engine. If someone has put washers under the under to raise it up and create more tension in the chain, remove them and see if that helps.
Lastly, add a link from the chain. You may have to remove the clutch and or the rear gear to do this but adding a link is a sure way to create some more slack in your chain.
Did Your Go Kart Stop Taking off when started? – Wrap Up
Let me know! Message me if this fixed your issue. If it didn’t message me and let me know what else I can help you with!
These are the most common issues that cause a go kart to take off when started. There may be a few more weird ones out there but start with these 4 easy solutions to fixing your go kart and become a Better Karter!