# GX340 shooting up in RPM



## JnC (Feb 21, 2014)

*Solved: GX340 shooting up in RPM (Video)*

*Edit: See video below*

So I recently put together an HS1132, a complete restoration. The engine was pulled apart as well as I had to do a few upgrades. 

Initially the machine fired up and would surge at high RPM and regardless of what I did to the max rpm adjustment screw it didnt help, I couldnt get past 3400 RPM, at the same time when I lowered the throttle the machine would just die, again adjusting the idle rpm screw on the carb didnt really help. 

So at this point I am stumped, think to myself it might be the governor as I recall taking it off while working on the motor. 

So I follow the service manual and the following link

http://www.ipspower.com/images/docu...justment-Info-GX240-270UT--GX340-GX390UT1.pdf

to adjust the governor, I also rebuilt the carb. 

Now after I put everything together, the machine fires up and the RPM shoot right up, even if the throttle is set at low. Increasing the throttle increase the RPM even more. 

I tried adjusting the cable but to no avail. 

Any ideas what I am doing wrong here? I feel like the governor adjustment instructions might be wrong.


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## Toro-8-2-4 (Dec 28, 2013)

I did not read the instructions you posted but I have seen this before and it was from the governor linkage not properly connected to the throttle lever. It looked OK at first glance but it was binding. I am not saying that is your problem but make sure the link is sitting properly in the Throttle lever slot and the spring is connected in the correct hole (I don't think there is.... but if there is more than one hole). 

If you still have issues list the upgrades you did as it may help others understand how to help you.


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## orangputeh (Nov 24, 2016)

i had the same problem. turned out to be the governor. i went thru it 5 times and i had the manual so thought had done it right.

fortunately i was able to look at another machine and it turned out that i had assembled the governor linkage wrong.

maybe someone can post a picture of that governor linkage. 

sorry , don't have enough experience to venture a guess on what else it could be.


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## JnC (Feb 21, 2014)

I think I have figured out the issue. 

The service manual and online instructions is wrong. 

If you are looking at the engine from above it says that the arm is pushed to the left to get WOT. Hence the service manual says to rotate the governor shaft clockwise whilst pushing the arm to left and then tightening the pinch nut, thats what I did earlier.

I just took of the air guide and noticed that I had the throttle at idle yet the throttle plate was wide open. 

So to get WOT the arm has to move right, not left per service manual. 

I am going to take the tank off later and undo what I did earlier and I'll report back.


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## DriverRider (Nov 20, 2016)

JnC said:


> So I recently put together an HS1132, a complete restoration. The engine was pulled apart as well as I had to do a few upgrades.
> 
> Initially the machine fired up and would surge at high RPM and regardless of what I did to the max rpm adjustment screw it didnt help, I couldnt get past 3400 RPM, at the same time when I lowered the throttle the machine would just die, again adjusting the idle rpm screw on the carb didnt really help.


The governor arm should more or less just flap in the breeze with the engine off and when running it should pull the throttle linkage in the direction of slow speeds, does it do this? Tension of the high speed spring on the arm is what sets high RPM.

Regardless of any governor problems the engine should run just fine manually holding the carb throttle valve from a slow position to fast. If it won't run steady manually holding the throttle then it has other problems be it spark, compression or carburetor.


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## JnC (Feb 21, 2014)

So the governor is all set, the governor arm needs to be pushed all the way to the left and the governor shaft needs to be turned all the way counter clockwise. The service manual states that the shaft needs to be turned clockwise i.e. same direction the arm pushes. 

Only issue now is to adjust the idle as it doesnt want to idle and dies when i bring the throttle lever down, the idle adjustment screw doesnt do anything to the idle RPM. I need to tinker with the cable I guess, any other ideas?


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## Jarsh (Jan 4, 2018)

Hi JnC,

I replaced the governor arm, both springs and rod on my 622 recently. The springs crossed each other and a vid that I had looked at had them in a straight line thus not touching. When I put the throttle plate/guide and filter cover back on it wouldn't idle down. In essence, it would have been the same as the revving the engine thus bypassing idle circuit. I moved the spring to the hole on the throttle lever just before the one I had used. It will now idle back to within range. 

I was going to adjust rpm's today but my tachometer isn't working as it should. It was -10C with a windchill of -17C so I'm thinking it was out of its operating range. I'll be trying it again on a warmer day. Before the flood on Saturday, I did get to try my machine last week and it now throws snow as it should. With the GX160 the governor shaft has to be turned clockwise from what I understand. Either way, after 3 years it's actually working now. Just wish I had done the work myself 3 years ago instead of messing with my useless dealer. Nothing but wasted time and frustration.


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## JnC (Feb 21, 2014)

Jarsh said:


> Hi JnC,
> 
> I replaced the governor arm, both springs and rod on my 622 recently. The springs crossed each other and a vid that I had looked at had them in a straight line thus not touching. When I put the throttle plate/guide and filter cover back on it wouldn't idle down. In essence, it would have been the same as the revving the engine thus bypassing idle circuit. I moved the spring to the hole on the throttle lever just before the one I had used. It will now idle back to within range.
> 
> I was going to adjust rpm's today but my tachometer isn't working as it should. It was -10C with a windchill of -17C so I'm thinking it was out of its operating range. I'll be trying it again on a warmer day. Before the flood on Saturday, I did get to try my machine last week and it now throws snow as it should. With the GX160 the governor shaft has to be turned clockwise from what I understand. Either way, after 3 years it's actually working now. Just wish I had done the work myself 3 years ago instead of messing with my useless dealer. Nothing but wasted time and frustration.


Wow, glad its all sorted now, nothing like investing in a decent machine only to have it not work when needed.


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## JnC (Feb 21, 2014)

So my governor issue is all set for MAX rpm but when I idle down the machine it dies. I have cranked the idle screw all the way in to see if that would help but to no avail. 

I still feel like like somewhere along the line something is not right with the governor. 

I did find the following post while searching for info, although the carb has been rebuilt I still want to go back in there and make sure the idle jet is not blocked. 



JamesReady said:


> Yosfam.... I just went through this issue with my HS1132.... She was surging like crazy and backfiring when not under load.....
> 
> The cause was a blocked idle jet.... It's the easiest thing to fix that I've even seen.... Here you go....(I hope you have a similar carb)...
> 
> ...


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## orangputeh (Nov 24, 2016)

JnC said:


> So my governor issue is all set for MAX rpm but when I idle down the machine it dies. I have cranked the idle screw all the way in to see if that would help but to no avail.
> 
> I still feel like like somewhere along the line something is not right with the governor.
> 
> I did find the following post while searching for info, although the carb has been rebuilt I still want to go back in there and make sure the idle jet is not blocked.


good idea about the idle jet. how about the gaskets? could be a vacuum leak somewhere.


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## Toro-8-2-4 (Dec 28, 2013)

YOu can easily clean the idle jet on these carbs as it is removable. You can even spay some carb cleaner through the air intake opening on the entrance of the carb and watch to see if and what comes out of the orifices into the body of the carb. Give it a good cleaning and rule anything in this area out. Good luck.


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## JnC (Feb 21, 2014)

Thanks, blower is at home, so I am intending on getting to it later today. 

I cant recall if I opened the crankcase cover when I built this motor as that was a year or so ago, if all else fails I am just going to rip open the whole **** thing to get to the source of the issue as I cant rest till I figure out the issue thats causing this problem.


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## JnC (Feb 21, 2014)

*Solved!!*

Both the issues are solved. 


The governor issue got solved by doing the following
- Loosen the pinch nut on the governor arm.
- Pull the governor lever (one with the spring/rod that connects to the throttle on the carb) to the right i.e. wide open throttle position and hold it there.
- Rotate the governor shaft that comes out of the engine block all the way counterclock wise (shop manual suggest to rotate it all the way clockwise, which is wrong) and tighten the pinch. 

For the idle issue
- The idle jet (plastic piece that sits below the idle adjustment screw and has the O ring on it) needs to be cleaned. 


I never even realized that the idle jet had a hole in it, it has to be the tiniest hole that I have ever seen on a carb, only way I was able to check it was shining a light through it and see I could notice it on the other side. The hole is no wider than the diameter of a human hair or two.


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## jrom (Jan 10, 2014)

Good going.

The only time I had a carb problem, I missed the hole in the idle jet too on the first round of cleaning.

Don't know if you have this Honda carburetor check sheet or not, but if not, it's a good one (downloadable hi-rez PDF): http://www.honda-engines-eu.com/documents/10912/31055/1483/e9844030-8016-4d4a-8d30-d1e8cd215253




JnC said:


> Both the issues are solved.
> For the idle issue
> - The idle jet (plastic piece that sits below the idle adjustment screw and has the O ring on it) needs to be cleaned.
> 
> I never even realized that the idle jet had a hole in it, it has to be the tiniest hole that I have ever seen on a carb, only way I was able to check it was shining a light through it and see I could notice it on the other side. The hole is no wider than the diameter of a human hair or two.


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## JnC (Feb 21, 2014)

^^ The first fix actually didnt work, the motor idle and ran fine but the governor wouldnt kick in when the engine got under load i.e when trying to snowblow, it eventually got fixed.


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