Vegas carts 670 mod runs slow

[wsl91]

I think I found the problem !!!
Cart is wired and everything is working including the tach

Idle speed 1400 rpm - explains hard to shift out of gear. need to figure out how to lower. Like I find on idle mix mine seems lean will drill the caps and back out .5 turns.

Belt slop is 3", motor is out of adjustment forward. Appears the aluminum motor mount plate is in backwards as the motor is almost hitting the rear axle now and the slots favor one end. I plan to turn around

Tach shows motor maxed out around 3200 rpm so that seems ok.

Not interested in a 40mph cart but 20 + would be good.

[slonomo]

That engine should be governed at around 3600 rpm, so 3200 is a little low. Look to your mixture screws to help with that.

The 670 I ran in my G1 would rev nicely and never felt as if it was running out of power. I did fiddle with the mixture screws quite a bit, ended up using a laser thermometer to take readings on the exhaust manifolds for mixture adjustments, worked quite well. I just tuned it by feel/ear then tried to match the temps on the manifold. Ran fantastic, no dead spots or anything.

I ended up changing out the cheap fuel pump in favor of a Briggs unit. I also removed the filter material in the pulse line. Changed the spark plugs, forget the type, it should be in my build.

https://www.buggiesgonewild.com/showthread.php?t=172738

I also removed the carb, disassembled and cleaned it, found metal shavings inside. The Chinese quality control is not great. I'd recommend doing that. You'll see in my thread what it looked like.

[wsl91]

with the cart parked and just working the throttle linkage it would govern at about 3500.

[slonomo]

The thing I like about using the engine governor is that you really can't over-rev it and damage it.

The thing I hate about using the engine governor is that you don't have max power/torque when the governor kicks in, it backs off the throttle.

On all of my Vtwins I loosened the governor lever bolt so that the lever would just ride on the bolt but would't grip it. When the governor rod would kick in, it wouldn't move the throttle and would just spin inside the lever. Essentially disables the governor.

Now, why would I do that? When climbing a steep hill or towing a heavier trailer I had full throttle control and nothing holding the power back. I would control the rpm myself by watching the tachometer. Rarely above 4000 rpm, and never above 4200 (unless it had a rev kit).

If you don't have any large hills to deal with or any trailers, then the governed rpm should be just fine.

[wsl91]

I've searched the forum, looked on You Tube, where do you set the idle speed? I find posts about idle mix. Mine is idling around 1400 and hard to get out of gear

[kgsc]

Idle speed should be set by a screw that the throttle arm hits on top of the carburetor. It will be horizontal to the ground. From another picture it looks like a black plastic screw with a 4 slot head

[wsl91]

I found it, the linkage wasn't returning up against the stop. fiddled with it a while then decided to adjust the linkage arm on the governor so it returns farther, that worked although a little change there is huge. Beginning to dislike the linkage, the throttle linkage binds a little and doesn't always return down without assistance, throttle return spring seems to not have nay tension when fully returned. Going to stop by HF tomorrow and look at the one on the shelf and compare springs. Previous owner may have it messed up

[slonomo]

I usually change the return springs out on my engines. The lawn/garden type engines were never set up to idle so the linkages are a little finicky. With a stiffer spring you should be good. I remember the 670 I had the throttle was actually pretty decent, better than the Vanguards I've had. Just that return spring was weak. I got the spring assortment at my local auto parts store.

Another alternative is to make a throttle linkage and use a bell crank to get the pedal to match the butterfly.

Here's the throttle linkage I made for my 23 Vanguard. It's adjustable and can work with any carb setup. Made it out of aluminum stock and small machine screws and washers. Worked flawlessly.
https://www.youtube.com/watch?v=lZyeDKMY40Y