Predator 346cc (11HP) Engine Issues

[OzFab]

That doesn't look right. Yes, that's the governor working but, it shouldn't snap the carb back to idle like that...

As I don't have much experience with the big block engines, I'll leave this one to the guys that do but, IMO, something needs adjusting...

 

[LGLDSR73]

That doesn't look right. Yes, that's the governor working but, it shouldn't snap the carb back to idle like that...

As I don't have much experience with the big block engines, I'll leave this one to the guys that do but, IMO, something needs adjusting...

Oh, not at all. It is returning to idle because I have significantly loosened the throttle lever which is returning to idle. I'm pulling on it and for the most part letting it return by itself.

The intent is to ultimately to run a cable to the pedal on a Kart.

...now, to defeat the Governor. They've always annoyed me. I had one on a Boss 320 Mustang back in the early 1970's. Was just as annoying but I worked around that....

 

[OzFab]

That shouldn't matter, there is still a force acting on the throttle lever; whether it be your hand or the tension on the nut, if the throttle lever is held in the open position, the governor shouldn't throw the carb back to idle; something is off...

 

[LGLDSR73]

That shouldn't matter, there is still a force acting on the throttle lever; whether it be your hand or the tension on the nut, if the throttle lever is held in the open position, the governor shouldn't throw the carb back to idle; something is off...

I think it's the way I am explaining it.

If I hold the throttle open the engine will not return to idle but rather will remain at whatever speed that throttle setting provides. When releasing the throttle it will return to idle due to the nut being loose and the spring tension.

As shown in this new video, if I open the throttle 100% you can see the Governor kick it back but not to idle. Using arbitrary numbers, if let's say if the throttle is opened wide it'll momentarily produce 3,500RPM. The Governor appears to ramp it back to perhaps 3,000RPM and you can see the rod beneath the fuel tank move back. Keep an eye on that rod beneath the tank when the throttle is opened wide.

Again, with respect to RPM this is all arbitrary numbers.

If however I pull directly on the throttle rod (that runs to the carb) and shown at the end of the video it appears to defeat the Governor altogether and there is nothing keeping the RPM's in check...conceivably throw a rod, etc., if held wide open.

Nev Video

Again, thanks!

 

[OzFab]

Ahh, that looks more like it...

You can adjust the governor to get a few more RPM out of it.

You are correct in that pushing directly on the arm overrides the governor; if the engine does wind up too high, the governor will let go before the rod does, the chances of the rod letting go are slim because the valves will start to bounce before it gets to that point.

With regard to governors, we usually suggest removing it completely as opposed to simply disconnecting it as the internal components are still working & will cause damage to the engine internals when (not if) they self destruct...

 

[Brandon1023]

I've been rebuilding my Maxima's 3.5 L V6, so small engines are a piece of cake for me now lol.

OP: I'm not sure if you think it's a problem, but that's how the throttle is supposed to work if you loosened the tension nut to allow it to swing back and forth with ease. On an out-of-the-box engine, that lever will stay in whatever position you put it in. On the lever is a spring which I believe pulls on the carburetor butterfly valve. It's been close to a year since I've messed with this go kart, so I can't remember without reassembling it. But one way or another, there's a spring that may be slightly larger, which connects the lever to the butterfly.

This valve is the one which is connected to the rod you described, which runs to the governor mechanism under the gas tank.

So basically, it's like a tug of war game. When you pull on the butterfly with the throttle arm lever (pic 1), the governor wins because it can overcome the tension of the spring (this is how it works to keep the engine in check. The tighter the spring, the higher the RPM). When you pull on the "Rod" that runs under the gas tank, you win the tug of war game, because you're pushing directly on it.

Try this sometime. Run the engine at normal idle speed (Somewhere around 1200 I believe?) and with 2 fingers, grab the rod that runs under the tank and gently start pulling it in the direction that makes the engine run faster and faster. The more the RPM climbs, the harder it's gonna get to keep that rod in place. This is the tug of war game I'm talking about. If you have any other questions, feel free to ask away. That's what people like me and Fabroman (who I remember learning a lot from a while back) use this forum for.. to help and share knowledge.