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I have a 2015 920021 Compact 24. The engine starts and runs correctly with no load and with light load. When the load is increased, the engine speed will steadily decrease to a very slow rpm until either A) the governor kicks in abruptly and the machine will surge forward until the cycle is repeated, or B) I back the machine away from the load because of fear that the engine will buck - or even die - because of low rpm. When I pull the machine away from load the engine will recover speed but not as abruptly. The point at which the governor kicks in varies from "about time" tardy to "I want to scream" tardy.

I had bought a wireless tachometer to make sure that the baseline revs are correct, but the tach was DOA from the box so getting that diagnostic info will be delayed for a while. My ear tells me that the no load idle might be 10-20% slow, but I'm unclear how that would affect the tardy governor kick-in. I did keep the machine inside overnight to thaw any potential ice buildup in the governor, and that made no difference.

Any thoughts/suggestions?
 

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It’s possible the carb has accumulated some varnish. The lean condition would cause it to handle load poorly.

With a cold engine, start the machine pull it off choke and give it a minute to warm up. Does the engine hunt. (Rpms surge up and down) after 60 seconds running the rpms should remain smooth. If hunting, does adding a little choke cause the rpms to smooth out.?

Next idle down the engine for a few seconds then quickly raise the throttle to full. Does the engine quickly and effectively rev to full or sputter and struggle.

Hunting and sputtering, clean the carb. Definitely check rpms once you get a working tach.
 

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Discussion Starter #3
It’s possible the carb has accumulated some varnish. The lean condition would cause it to handle load poorly.

With a cold engine, start the machine pull it off choke and give it a minute to warm up. Does the engine hunt. (Rpms surge up and down) after 60 seconds running the rpms should remain smooth. If hunting, does adding a little choke cause the rpms to smooth out.?

Next idle down the engine for a few seconds then quickly raise the throttle to full. Does the engine quickly and effectively rev to full or sputter and struggle.

Hunting and sputtering, clean the carb. Definitely check rpms once you get a working tach.
The engine starts perfectly every time, requiring minimum choke and then none to run without stumbles or surges. And when under load and full speed when the governor kicks in the engine runs perfectly as well. I've had gummed up carb issues before and this doesn't seem to follow a similar path.
 

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Gotcha, so you have the machine lugging under load and rpms continue to fall. You release both auger and drive levers, the engine takes an unusual amount of time to return to full rpms? It stumbles for more then 2 seconds before springing back to full revs?

I’d love a video of this. Can’t hurt to clean the carb or at least drop the bowl to check for water contamination, or sediment. Lately I’ve even replaced relatively new spark plugs that caused poor engine performance.
 

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The first thing I would do is remove the carburetor heater box (the shroud around it), so that you can watch the governor linkage, and the actual throttle plate arm, during operation.

If the governor linkage is binding or dragging for some reason, and is unable to open the throttle plate, then that's your problem. Lubricate it, move whatever is interfering with it, etc. Your symptoms do kind of sound like this, though it isn't common, as far as I know. You would also now have access to the throttle plate arm, so you can open/close it manually, to observe what the engine does. Don't over-rev it, of course, or you could blow the engine apart. Move the linkage and throttle plate with the engine off, as well. Risk-free, and would let you feel how easily they move.

If, however, the governor is pulling the throttle plate arm open as soon as the RPMs drop, but the engine speed continues to falter, then you have a carburetor-type problem. Or at least, you can better understand what you're dealing with. Something likely related to fuel/air. A gummed up carb (though the symptoms don't really sound like that), and air leak, etc.

As just an easy test, does adding a little choke help at all? If you weren't getting enough fuel (running lean), adding choke might help, and could give some insight as to what's going on.
 

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Discussion Starter #7
Gotcha, so you have the machine lugging under load and rpms continue to fall. You release both auger and drive levers, the engine takes an unusual amount of time to return to full rpms? It stumbles for more then 2 seconds before springing back to full revs?
If I put the snowblower into deep snow and proceed at the slowest forward speed the engine will slowly lose revs and the chute output will steadily drop. When the engine seems to slow down to where it must start to buck and/or stall, then (and only then) the governor kicks in and engine revs go up abruptly without stumbling and snow output returns to normal. If I don't wait for the governor to kick in and instead disengage the drive and pull the machine backward away from the load the engine (and impeller) speed will return to normal, but more gradually than when the governor kicks in.

The primary issue is the bogging down before the governor kicks in. I have another similar machine and the revs do decrease under load but return to normal with none of the drama of the machine in my post. I'll work on that video!
 

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Discussion Starter #8
Governor disconnected.
Choke remaining near closed.

Any black smoke while it bogs down?
The governor works at least enough to consistently rev the engine when it's slowed to near-stall speed under load. The issue is that the needed speed increase is very late to the party when it does kick in. I believe that the choke works as intended. The engine needs choke to start and is happy when choke is removed after 20-30 seconds of run time. No black smoke, and only a little typical smoke when cold-started.
 

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Try loosening the gas cap a bit, and put the machine under load.
Although somewhat rare, a blocked vent in your gas cap would starve the engine for fuel.
No doubt it's a spring loaded vent for evaporative purposes, it may be hanging up.
 

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The first thing I would do is remove the carburetor heater box (the shroud around it), so that you can watch the governor linkage, and the actual throttle plate arm, during operation.

If the governor linkage is binding or dragging for some reason, and is unable to open the throttle plate, then that's your problem. Lubricate it, move whatever is interfering with it, etc. Your symptoms do kind of sound like this, though it isn't common, as far as I know. You would also now have access to the throttle plate arm, so you can open/close it manually, to observe what the engine does. Don't over-rev it, of course, or you could blow the engine apart. Move the linkage and throttle plate with the engine off, as well. Risk-free, and would let you feel how easily they move.

If, however, the governor is pulling the throttle plate arm open as soon as the RPMs drop, but the engine speed continues to falter, then you have a carburetor-type problem. Or at least, you can better understand what you're dealing with. Something likely related to fuel/air. A gummed up carb (though the symptoms don't really sound like that), and air leak, etc.

As just an easy test, does adding a little choke help at all? If you weren't getting enough fuel (running lean), adding choke might help, and could give some insight as to what's going on.
I missed your post the first time through, sorry. All good stuff. I should be able to get to it this afternoon. Thanks!
 

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Try loosening the gas cap a bit, and put the machine under load.
Although somewhat rare, a blocked vent in your gas cap would starve the engine for fuel.
No doubt it's a spring loaded vent for evaporative purposes, it may be hanging up.
I did try that, to no avail. I had seen that discussed regarding some of the newer gas caps, but not the Compact 24. I forgot to mention that I had tried; sorry!
 

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The gradual loss of power suggests a fuel flow issue and would check flow at carb inlet from tank and then at float valve with bowl removed also checking for sticking float action.:wink2:
 

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The gradual loss of power suggests a fuel flow issue and would check flow at carb inlet from tank and then at float valve with bowl removed.:wink2:
What fuel flow impediment could cause gradual speed loss under load but still consistently allow revving from near bogging speed to the same nearly normal (and very usable) speed? Not skeptical, just interested in what carb scenario could consistently slow and then surge engine speed? I would think that a disconnected throttle plate would not have consistent and gradual symptoms, and I'm not clear how you could envision a carb float responding to load, as only a fuel level change in the bowl would trip the flow valve and it only takes 3-5 feet of deep snow running to trigger the run down/rev up cycle. Hardly enough use to significantly change float bowl fuel levels, no?

My sense is that the bogging down is normal for the load, and that the power is there to overcome load if requested, but the governor is just not reacting quickly enough to make the compensation relatively seamless. I'll explore all suggestions, but I am going to key on the governor and throttle plate area, b/c that seems to be the likeliest perp.
 

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I must dissent with the masses. To me, this sounds like the gov shaft is gunked up, and won't allow movement until the speed drops enough to put enough pressure on it to break free. Check the gov arm for free motion, and clean and lightly lube the gov shaft where is comes out of the engine case. Also verify that the throttle plate on the carb is not similarly gunked up and sticking . . . .
 

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What fuel flow impediment could cause gradual speed loss under load but still consistently allow revving from near bogging speed to the same nearly normal (and very usable) speed? Not skeptical, just interested in what carb scenario could consistently slow and then surge engine speed? I would think that a disconnected throttle plate would not have consistent and gradual symptoms, and I'm not clear how you could envision a carb float responding to load, as only a fuel level change in the bowl would trip the flow valve and it only takes 3-5 feet of deep snow running to trigger the run down/rev up cycle. Hardly enough use to significantly change float bowl fuel levels, no?

My sense is that the bogging down is normal for the load, and that the power is there to overcome load if requested, but the governor is just not reacting quickly enough to make the compensation relatively seamless. I'll explore all suggestions, but I am going to key on the governor and throttle plate area, b/c that seems to be the likeliest perp.
A governor is an all mechanical device which is usually trouble free unless screwed up by accident, misuse or abuse. If the throttle and linkages are hooked up correctly (is there reason to suspect they are not) and will hold an RPM from idle to full speed it is probably OK.

Surging under load can be a common indicator of a fuel flow problem on any engine. An engine under no load can run on just a trickle of fuel, when under load fuel demands increase and if a proper amount is not kept available in the fuel bowl engine RPM will decrease lowering the fuel demand. When this happens fuel bowl gets a chance to refill increasing RPM until fuel level drops once again repeating over and over causing a surge.:smile2:
 
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I have a 2015 920021 Compact 24. The engine starts and runs correctly with no load and with light load. When the load is increased, the engine speed will steadily decrease to a very slow rpm Any thoughts/suggestions?
If the power loss starts at around the 1 minute or so mark into usage that could be another indicator of running out of available fuel in bowl.
 

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It sounds like a sticky or under-sensitive governor to me. If it lugs down to a point and then throttles up and runs fine putting out normal power at normal rpm, I doubt it's a fuel issue.
 

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It sounds like a sticky or under-sensitive governor to me. If it lugs down to a point and then throttles up and runs fine putting out normal power at normal rpm, I doubt it's a fuel issue.
What exactly is an under sensitive governor? Did it have a different gear installed, different bushing, spring or what from the other 100k?
 

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Under-sensitive would be one that's damaged in some way or not hooked up right so it's not making enough of a throttle adjustment until the revs have dropped a lot. Chances are, something is just sticking, so it doesn't get the throttle open until it's trying to move it far enough and applying enough force.
 
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