Honda over speeding badly, suspect governor internals but don't think it the issue.

[trouts2]

Problem: Engine over speeds to roughly 4,500 – 5,500rpm. The dash throtle control has no influence on speed, 0.

Background info:

I changed the gas filter. On the 11/32 that required taking of the gas tank. At the same time I took the carb off and cleaned it. The engine over speeds ever since. I have reset the governor many times along with some jets and stops adjustments to no effect.

Honda 11/32 snowblower. Engine GX340

After a factory manual governor adjust, several times, the engine over speeds.
The setting was:

1 Put the throttle to full speed.

2 Loosen the governor arm screw.

3 Push the gov arm max forward so the butterfly is max open.

4 Turn the governor engine gov adjuster fully clockwise.

With the throttle on the dash off and I move the governor arm with a finger from it’s home position it returns to it’s start position without force but returns. When at full throttle and I move it off its home position snaps back strongly to its home position with a bang, normal.

Starts on the first pull.

Does not change speed with the dash throttle in any position.

Will run at low speed with a little choke. When the choke lever goes from full choke to less choke it over speeds to around 4000, 5000 rmp.

The throttle butterfly never returns to be shut when stopped i.e throttle to very slow.

The spring moved by the throttle cable seems fine not stretched. It goes from an arm controlled by the throttle lever on the dash to the governor. The spring is original and I think in good shape. When the throttle is set to low speed the spring is loose on it’s connections. When the throttle on the dash is set to fast the spring has a lot of pull on the back part of the governor arm.



The spring on the governor that goes from the end of the governor arm to the throttle part on the top of the carb is in excellent shape. The coiled section is not stretched at all. I suspect the governor interals are broken.

The governor controlled butterfly should be closed when the engine is in low throttle but remains open and close to fully open. I have tried all I could to get the butterfly to close when off but unsuccessful. To me that seems like broken internal parts. But that does not make sense as it ran fine before I changed the gas tank spring.

Questions:

When I start it with a little choke and the throttle on the dash set to very low speed

it starts and runs slowly and fine. If I put the throttle to fast there is no response.

If I reduce the throtle there is no speed change. Speed changes only happened with moving the choke lever a little. If I move the choke lever to off it overs speeds immediately.

I am not sure but think the internal arms on startup likely push out a bit to close the throttle to reduce speed. Since that does not happen I suspect the governor internals are broken but don’t see how that happened. Are the governor internals broken?

What carb adjustments could cause extreme rpm’s. I know carb high and low carb adjustments can influence speed buy the range is fairly mild versus extreme.

 

[Fordiesel69]

Is the throttle shaft stuck? Or linkage binding.

I always reset the gov shaft when troubleshooting. I put the cable to full then hold gov arm to full and turn the gov shaft CLOCKWISE. Then tighten the gov arm bolt. That resets the arm to shaft, and allows the gear to flyweights have zero play.

 

[mk378]

The "idle stop" screw on the throttle plate shaft controls the minimum speed. If you pull the arm and linkage against the spring so that the throttle lever on the carb is resting against the screw, the engine should run slower than normal. If it is too fast like that, turn the screw out so that the throttle plate can close more. You want a smooth slow run.

If the carb has a low speed mixture screw, this is the time to adjust it. Set that for maximum rpm with the throttle held against the slow stop. Then open the mixture screw slightly as a slightly rich mixture will have more reliable running especially cold. Reduce the slow speed more if necessary after improving the mixture.

When the operator control is on "turtle", the governor arm should move all the way back to the slow stop as soon as the engine is started. Even on "rabbit", with no load the throttle plate will still be nearly closed at governed rpm.

All these tests are with the machine clutch disengaged so there is no load on the engine.

 

[trouts2]

>>Is the throttle shaft stuck? Or linkage binding.<<

I have checked all of parts related to the carb and gov arm and have not found anything binding or sticking; the plate that the throttle cable move to tension the big governor sprint, the settings screws, the throttle part where the governor arm attaches on top of the carb, the small spring on the governor rod & etc. All the parts involved have their expected movement and range of travel. I have checked them many times as I have been working on this issue for a long time. Since I have not found a cure I have either missed something or the governor internals do not fly out as expected. ??

>> I put the cable to full<<

I think you are referring to the throttle cable to max fast. Most directions set the throttle cable to max. That tightens the big spring to the back of the governor arm. That spring causes the governor arm to push the governor rod to push the rod towards the carb connection controlling the butterfly. It is always causing the butterfly to stay max open for more airflow, more gas. So the throttle spring tension at max opens the butterfly open for max air and gas. The governor’s job is to reduce speed to match the tension on the big spring i.e. keep the butter open but only enough to match max throttle which I think would be set at 3600 rpm. When a load happens, rpms slow and the internal governor weights don’t fly out to push the arm out so the spring tension can pull the governor arm more for more air, gas and rpn. The engine will try to over speed past 3600. The increasing speed causes the weights inside the engine to fly out more causing the governor arm to have more resistance to the big spring and keep the engine at 3600.
I wrote that not to inform you as you likely know this stuff but to explain my understanding of how the governor works.

>>then hold gov arm to full and turn the gov shaft CLOCKWISE.<<
Yes, clockwise.

>> Then tighten the gov arm bolt. That resets the arm to shaft, and allows the gear to flyweights have zero play.<<
OK.

What I am puzzled about is if there is any rotation of the pin at all i.e. the governor internals are broken.
I set the governor per the directions in this video:

 

[mk378]

Yes, clockwise.

In the video, the guy turns the internal shaft counterclockwise then locks it down. This causes the inside end of the shaft to rest against the centrifugal weight unit. When the engine is turning, force will be applied to the shaft in a way that opposes the spring. However your engine is built, you need to turn the shaft the same way that the spring pulls on the arm. In the engine in the video, the spring is pulling the arm counterclockwise.

 

[trouts2]

In the video, the guy turns the internal shaft counterclockwise then locks it down. This causes the inside end of the shaft to rest against the centrifugal weight unit. When the engine is turning, force will be applied to the shaft in a way that opposes the spring. However your engine is built, you need to turn the shaft the same way that the spring pulls on the arm. In the engine in the video, the spring is pulling the arm counterclockwise.

MK378 I was unsure of that along with not knowing in more detail about how the throttle and governor interact on that machine.

In the video, the guy turns the internal shaft counterclockwise then locks it down. This causes the inside end of the shaft to rest against the centrifugal weight unit. When the engine is turning, force will be applied to the shaft in a way that opposes the spring. However your engine is built, you need to turn the shaft the same way that the spring pulls on the arm. In the engine in the video, the spring is pulling the arm counterclockwise.

 

[trouts2]

The 11/32 is now running fine, no overspeeding. High and low speed on the dash throttle are set to proper max and min rpm and held correctly by the governor arm. Nothing was broken internally. It was lack of more specific governor and throttle parts inaction knowledge that held me up from getting a fix. I spent a few days on the net reading articles and forum posts about governor operation that got me adjusting components right and realizing the governor internals were fine and just needed proper settings along with multiple scrubbings of the carb.
The biggest issue was not understanding how only the governor arm moved the carb moved the throat butterfly air speed. Another was that the big spring the dash throttle set the tension on was a key factor in having the governor work properly.
Another issue was I could not watch the governor move to confirm if it was broken and not interacting right with the big tension spring.
With the Honda gas tank off I setup a Tecumseh tank with a long gas line to the carb so I could run the machine with the tank next to the Honda on a stood. I ran it with settings such that the arm could not cause the butterfly to over speed. It would not run right but from there I started making adjustments with the throttle spring tension to get the engine to run slowly and not overspeeding.
A big misunderstanding I had was I thought the spring was not so important. I thought that yes it worked against the fly weights inside the engine that controlled the governor pin to turn but did not realize how much spring tension there was is critical. I thought that the internal flyweigh travel moved the right amount distance wise based on rpm versus the spring tension sets the rpm. No knowing that caused big problems. My original thinking was the spring just applied tension but how much was not important. That was a big mistake in all this. After reading a bunch I started tweaking the arm setting along with the spring tension. That led to more insight as I ran the engine with faster settings but no overspeeding. I kept tweaking the spring tension and the gov arm setting to get the governor steady at 3,600rpm. I then set the low rpm in the standard was. It was and akward way to get the thing tamed but it is now running properly. Should I ever go in there again setting the governor will be cake and all go well.
In the past I have reset governors many times. I have installed governor internal parts and know what they do. But the way the Honda was designed was a bit different than I realized and getting to understand that took a long time as I never knew it was an important factor.