Adjusting GC160 governor for reduced RPMs

[FarmerCharlie]

I put a GC160 in a new go kart for my grandkids, and the max speed is a little too high for my taste. I suppose I could limit the throttle adjustment, but that would also restrict the power at slow speed. Is it practical to adjust the governor to limit the the max RPMs to a lower value?

If that is not practical, I guess I could go to a larger sprocket on the drive wheel, but that would also restrict the ground clearance of the chain.

 

[SAFETYpin]

I know from a GX160 perspective that the governor is operated from weights. The only way to change the rpm its set for is to change the weights or adding springs so it takes more centrifugal effort from the governor to close the throttle. You could try to inspect the mechanism and look for the spring that's the governor is working against and change it out for a lighter spring, maybe.

 

[Strigoi]

if you go to a bigger sprocket to slow down the top speed it will make it accelerate faster.

 

[rasndas]

You can lower the engine speed with the govenor. There should be an adjustment screw on the throttle arm on the engine that limits the amout of travel it has at full throttle. This is probably located unde the air cleaner but is accesible with a long screw driver. This screw runs through a coil spring which keeps it from backing out. By turning this screw in you will lower the maximum rpm the engine will turn without affecting the bottom end performance.

 

[FarmerCharlie]

Throttle cable interfering with governor?

In replacing the manual throttle control with a throttle cable, I am worried that my first plan may be problematic.

I had thought I would just connect the cable to the manual throttle lever, but in looking at it more closely, I am wondering if that would interfere with the operation of the governor. This figure, with the gas tank removed, shows the throttle lever with the spring connected at the bottom.
http://i823.photobucket.com/albums/zz159/FarmerCharlie/web/Farm/Equipment/IMG_5265_crop_800w.jpg
I am assuming that the spring is what lets the governor pull the throttle back if the RPMs go too high.
This shows the throttle cable connecting through the same hole as the spring.
http://i823.photobucket.com/albums/zz159/FarmerCharlie/web/Farm/Equipment/IMG_5269_crop_800w.jpg
My concern is that if someone is pushing the foot pedal down, then that would prevent the spring from being able to limit the throttle.

Is there a way to connect a throttle cable on this engine without interfering with the governor?

 

[SAFETYpin]

In replacing the manual throttle control with a throttle cable, I am worried that my first plan may be problematic.

I had thought I would just connect the cable to the manual throttle lever, but in looking at it more closely, I am wondering if that would interfere with the operation of the governor. This figure, with the gas tank removed, shows the throttle lever with the spring connected at the bottom.
http://i823.photobucket.com/albums/zz159/FarmerCharlie/web/Farm/Equipment/IMG_5265_crop_800w.jpg
I am assuming that the spring is what lets the governor pull the throttle back if the RPMs go too high.
This shows the throttle cable connecting through the same hole as the spring.
http://i823.photobucket.com/albums/zz159/FarmerCharlie/web/Farm/Equipment/IMG_5269_crop_800w.jpg
My concern is that if someone is pushing the foot pedal down, then that would prevent the spring from being able to limit the throttle.

Is there a way to connect a throttle cable on this engine without interfering with the governor?

That looks ok to me, it shouldn't bypass the governor with that hook up. I would probably drill a hole in that arm for a barrel cable stop like this. Just to be sure that the cable doesn't interfere with that spring.

If you also loosen the 10mm nut it should help the throttle close when you let off the gas, or there should be a wave washer located under that throttle arm that you could remove, it applys drag to the throttle so it stays where you set it. (if its similar to a GX160)

Good Luck

 

[SAFETYpin]

I just notice a black switch on the arm too... I assume it kills the ignition when you return the throttle lever to idle? If so you'll need to remove that switch and relocate it to turn the engine off, otherwise it will shut off every time you let off the gas.

 

[FarmerCharlie]

I just notice a black switch on the arm too... I assume it kills the ignition when you return the throttle lever to idle? If so you'll need to remove that switch and relocate it to turn the engine off, otherwise it will shut off every time you let off the gas.

Thanks. I hooked it up just like you said, and it works great. I couldn't find a barrel clamp locally, so I just looped the cable through the hole and secured it with a cable tie and some duct tape. I did have to add a spring between the throttle lever and the bracket just above the "D" in your label to help close the throttle. Without that spring it did not come back to idle reliably.

I also disconnected the wire to the kill switch and connected it to the kill switch wire that came with the kart.
Here it is in action:
YouTube - ‪MVI 5288‬‏

 

[SAFETYpin]

Great job

 

[FarmerCharlie]

Engine cutting out and stalling at slow speed

The kids have been riding the kart today. It runs great at high speeds, but it cuts out at low speeds, and even quit twice at low speed. My friend who knows a good bit about gasoline engines came over to look at it, and he thinks it is running too rich at low speed. We could not find a way to adjust it. The manual did mention having it reset for high altitude, and he thought that might help. But the manual also says that running it at low altitude with a high altitude setting could damage the engine. My altitude is 750 feet.

Any opinions? I sure miss the old days when we could adjust engines as needed.

I have the same engine in a water pump, and it works fine. I know that these engines are used mostly for applications where they run at a constant high speed, and I am wondering if I should have followed my original plan to get an old used engine.

 

[SAFETYpin]

I would adjust the idle speed up... Unless your clutch is starting to engage. Theres probably a idle mix screw but I didnt get a ton of response out of mine on the GX160. It should be number 4 in the diagram. There might be alittle shoulder/cap that prevents you from turning it much. That cap on the screw just pulls off with some force. Idle speed appears to be number 6.

I would be surprised if it was running rich... most of the time the carbs are set on the lean side trying to get them to run as clean as possible. A dirty air filter could cause a rich condition. Your spark plug should tell you how the fuel mix is, unfortunately reading a spark plug is a lost art these days. The manual is worried about it running too lean if you set it up for high altitude but run it closer to sea level. Pull the spark plug and check the insulator to see its white=lean or black and sooty=rich.

Plug reading video

 

[FarmerCharlie]

Pull the spark plug and check the insulator to see its white=lean or black and sooty=rich.

Here are a couple of pictures of the plug. The first is with a flash, and the second is in sunlight.
https://www5.vetmed.auburn.edu/~branch/images/FarmEquipment/GoKart/IMG_5305_crop_800h.jpg
https://www5.vetmed.auburn.edu/~branch/images/FarmEquipment/GoKart/IMG_5315_crop.jpg
There was lots of soot, some of which even fell off onto the paper towel.

Did I mention that it wouldn't crank after it quit the last time?
I cleaned the plug, and now it's running again--at least for now.

I do think this engine is probably too big for this cart when driving on the bumpy fields and trails I have. Even at pretty good speed the engine sounds like it's loafing. It gets up to what sounds like a normal RPM only during acceleration.

 

[SAFETYpin]

Well its hard to argue with that, it definitely looks rich. What's the history on the engine was it used on something else or brand new out of the box.....? Do you know if someone has previously modified the carb?

I would suggest putting a fresh plug in it and taking it out somewhere you can run it wide open. Do a high speed run and turn it off before coming to a stop, pull the spark plug and check it out. If that looks good than your main jet is about the right size, if not you should probably change it. Looks like the main jet is #10 on that break down, usually just a brass piece with a small fixed orifice. It should just unscrew with a flat bladed screw driver. Looks to me like you need a smaller main. What size is in it and what size did the manual recommend for high altitude operation?

I would also check the airfilter and make sure the choke is actually in the off/open position.

 

[FarmerCharlie]

Well its hard to argue with that, it definitely looks rich. What's the history on the engine was it used on something else or brand new out of the box.....? Do you know if someone has previously modified the carb?

It's brand new from Tractor Supply. I would have bought a Briggs, but they only had the bigger Briggs engine in stock, and the kids were getting tired of pushing each other around the driveway.

I would suggest putting a fresh plug in it and taking it out somewhere you can run it wide open. Do a high speed run and turn it off before coming to a stop, pull the spark plug and check it out. If that looks good than your main jet is about the right size, if not you should probably change it. Looks like the main jet is #10 on that break down, usually just a brass piece with a small fixed orifice. It should just unscrew with a flat bladed screw driver. Looks to me like you need a smaller main. What size is in it and what size did the manual recommend for high altitude operation?

I would also check the airfilter and make sure the choke is actually in the off/open position.

I may be able to get my friend to do a real test drive like you suggest.
I did notice that with the kids driving it, their foot was bouncing around on the gas pedal a lot, so the engine was constantly speeding up and slowing down, but mostly going pretty slow. Good point about the choke; but the choke definitely does seem to be operating. And re high altitude, the manual just said to take it to a dealer for that modification. I may just take it to a Honda dealer to see if they can check it out. Hope I didn't void the warranty by drilling the holes for the cable and spring. And if I did, then oh well--it's just the kids inheritance.

 

[SAFETYpin]

I am kind of shocked that its running that rich being brand new. You can use a propane torch to burn the spark plug clean. Just hold the torch on the built up carbon and get the plugs good a hot for a bit. You should see that carbon disappear. Beware, if you overheat the plug it can crack the porcelain insulator.

Does anyone know if the GX and GC engines share main jets?

If they do there's a ton of sites out there with jets. You could purchase one that's too small and get some tiny drills and size it to what you need. Or take a guess and go with a smaller main jet.

Being that its brand new, you might be better off trying to get it serviced or get tech info directly from Honda. I would hate to give you advice that could cost you the engine.

 

[pickupman6]

he said it ran good on the top end and at low speed it was cutting out. if i remember correctly it has a idle mixture screw. i would recommend turning it all the way in then back out 1.5 turns. that is what controls your fuel ratio from idle to about 1/4 throttle.