Box Stock

420 governor issue

Mac_49

Mac_49

Member
Working on a golf cart here...trying to understand the governor setup.
It's not engaging as the Mychron is reading in the 4,000's.
I had to build a custom throttle bracket and mount different springs as well as locations of the springs. I'm assuming it's a spring tension issue but wanted to see if I'm missing something else.
Are governors setup with specific spring tensions that give it the 3,600 rpm "govern"?
If so....is there some sort of spring tension chart that'll overlay what rpms each setup gives?
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I doubt there's a spring chart .
The black one , change that too a lighter one , as a test . . Also you throttle spring , does it stretch enough to let the arm work ?
 
flattop1 said:
I doubt there's a spring chart .
The black one , change that too a lighter one , as a test . . Also you throttle spring , does it stretch enough to let the arm work ?
Click to expand...
The black spring is a pretty stout one already being stretched...I can see if there's a different throttle spring though. Is there a way to "weaken" a spring? I could try that and see if there's a good spot to "weaken" it to?
 
not really heat would be the onlty thing and failre is likely .
hardware store should have a bunch of springs .
screen door springs are pretty handy .
 
flattop1 said:
How close to the factory spring set up is it now . Trying to emulate that seems critical .
Click to expand...
It's not close honestly. Both springs aren't the originals. I had to use different ones to make the throttle setup work.
My only other thought here....is to go pvl setup running the black briggs coil.
But springs are a lot cheaper haha.
 
Could add an adjuster or spring tensioner to the one that controls the govenor , assume its the black spring .
reduce the tension on that it should operate .
Once you get it too function fine tuning the set up is easy .
So your at 4000 rpm and want less? then you need a stronger black spring .
 
flattop1 said:
Could add an adjuster or spring tensioner to the one that controls the govenor , assume its the black spring .
reduce the tension on that it should operate .
Once you get it too function fine tuning the set up is easy .
So your at 4000 rpm and want less? then you need a stronger black spring .
Click to expand...
I see what you're saying. I think adding a stronger 'black' spring might be my first step.
I'm well over 4k when I was testing and I could've gone more but knew better. So I need some sort of "governor" to come in before someone else drives it and blows the motor not knowing what's going on.
 
The angle of the back spring looks off as well . More too the left would be better .
As near 90* as possible to the lever and arm pivot .
 
flattop1 said:
The angle of the back spring looks off as well . More too the left would be better .
As near 90* as possible to the lever and arm pivot .
Click to expand...
I could tinker with that. I bought a couple throttle springs I'm going to try and experiment with hoping that'll help as well.
 
Might Need Dual levers on the throttle side . The govenor has to be able too over come the throttle cable pulling on it . Or at least longer spring .
 
Update:
I was able to get the spring tension well off so that it'll govern around 3,200.
If I add a light smaller spring I can get just a tick over 4k on a down hill slope. Roughly 3,800 on flat.
Question is...will that little extra above "stock" governor be ok for long durations as we're constantly on the governor driving and golfing all day. Or should I keep trying to get to the 3,600 max?
 
Some of these engines have a separate ignition rev limiter.

By design the flywheel and internals should take many RPM as the stock valve springs will allow..
Intermittently, refer to what flattop said :D
 
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