Yamaha G2 Running Erratically

[timquagliata]

I have a Yamaha G2 gas golf cart. The cart runs great except it every once in a while it will randomly slow down for a second or two and then speed back up. It usually does this higher speeds. Any thoughts?

[CP241]

Do you have the governor nut tightened all the way down? Sounds like you're hitting the rev limiter

[slonomo]

If the engine cuts out, it could be the fuel level. If the float is not adjusted properly it could be running out of fuel at higher rpms under load.

[timquagliata]

I’ll check this out.

[CP241]

Originally Posted by timquagliata

I’ll check this out.

Loosen the 10mm nut on the governor shaft (above the secondary clutch) 5-10 full turns and see if it's any better. Then you can tighten it 1 turn at a time until it hits the rev limiter again, and then back it back off a turn.

[cgtech]

A G2 will run fine with the governor nut cranked all the way up! (& Even spring "flipped", not literally). I think only the G9 had a built in RPM limiter. Either way, the only way it's over-revving & causing cutback is one of 3 things. Governor bypassed straight to carb throttle cable, governor is connected but inoperative (a big sign you better fix it in the axle before axle is damaged), or bad clutch/belt problems. I guess there is a fourth possibility, faulty ignitor that's cutting spark too soon, but that's not how they typically fail (they typically fail with really lame ignition timing curves, low power, late timing, or fail no spark at all which is least common).

I have never seen a G2 or G9 hit "rev limiter" type speeds that had these three things met-
-Throttle cable still connected to governor (not cable bypassed straight to carb)
-Governor not messed up in axle
-Clutches & belts working correctly

I have never seen a faulty ignition box help/allow it to get to "too high" rpms.

Does this thing reach "screaming" rpms when it cuts out?

Oddly, I have heard of clutch issues doing this "wierd stuff" at reasonable rpms from very smart folks who also have years of experience as I do. Just how sure that your clutches/belt are working good? Just what belt is on it?

[CP241]

Originally Posted by cgtech

A G2 will run fine with the governor nut cranked all the way up! (& Even spring "flipped", not literally). I think only the G9 had a built in RPM limiter. Either way, the only way it's over-revving & causing cutback is one of 3 things. Governor bypassed straight to carb throttle cable, governor is connected but inoperative (a big sign you better fix it in the axle before axle is damaged), or bad clutch/belt problems. I guess there is a fourth possibility, faulty ignitor that's cutting spark too soon, but that's not how they typically fail (they typically fail with really lame ignition timing curves, low power, late timing, or fail no spark at all which is least common).

I have never seen a G2 or G9 hit "rev limiter" type speeds that had these three things met-
-Throttle cable still connected to governor (not cable bypassed straight to carb)
-Governor not messed up in axle
-Clutches & belts working correctly

I have never seen a faulty ignition box help/allow it to get to "too high" rpms.

Does this thing reach "screaming" rpms when it cuts out?

Oddly, I have heard of clutch issues doing this "wierd stuff" at reasonable rpms from very smart folks who also have years of experience as I do. Just how sure that your clutches/belt are working good? Just what belt is on it?

Clutch issue would be my second guess, but it doesnt sound like it does it all the time, just occasionally (at least that's how I read it). I'd think a clutch or belt problem would be a lot more frequent and problematic rather than just once in a while.

the G2 absolutely does have a rev limiter built into the ignitor. Rebuilding my G2 now and had the governor stick due to the cable and had it bouncing off the rev limiter a couple times. Which is another possibility if the cable doesnt return when the governor tries to pull it back.

[timquagliata]

Originally Posted by cgtech

A G2 will run fine with the governor nut cranked all the way up! (& Even spring "flipped", not literally). I think only the G9 had a built in RPM limiter. Either way, the only way it's over-revving & causing cutback is one of 3 things. Governor bypassed straight to carb throttle cable, governor is connected but inoperative (a big sign you better fix it in the axle before axle is damaged), or bad clutch/belt problems. I guess there is a fourth possibility, faulty ignitor that's cutting spark too soon, but that's not how they typically fail (they typically fail with really lame ignition timing curves, low power, late timing, or fail no spark at all which is least common).

I have never seen a G2 or G9 hit "rev limiter" type speeds that had these three things met-
-Throttle cable still connected to governor (not cable bypassed straight to carb)
-Governor not messed up in axle
-Clutches & belts working correctly

I have never seen a faulty ignition box help/allow it to get to "too high" rpms.

Does this thing reach "screaming" rpms when it cuts out?

Oddly, I have heard of clutch issues doing this "wierd stuff" at reasonable rpms from very smart folks who also have years of experience as I do. Just how sure that your clutches/belt are working good? Just what belt is on it?

OK, I think I attached two images. One of the images shows that governor has not been bypassed. The other image is of my clutch. I was wondering if anyone could tell by looking at it if needs to be replaced. Please let me know if you can't see the images.

[CP241]

Originally Posted by timquagliata

OK, I think I attached two images. One of the images shows that governor has not been bypassed. The other image is of my clutch. I was wondering if anyone could tell by looking at it if needs to be replaced. Please let me know if you can't see the images.

Your belt has definitely seen better days.

Can you take a video of the cart in neutral and rev the engine so we can see thr clutch operation?

Your belt is shot for sure. But before replacing the belt it's best to watch both clutches work to verify they transition smoothly between each other

[CP241]

This is a carryall, but shows where the belt should sit on the secondary clutch if the clutch and belt are both good. Nice and flush with the top.of the clutch sheaves.