Ariens SnowBlower Governor / Throttle

[lefty]

Ariens:
Model:924050
Serial:112958

I can't find the model on the engine. The sticker that is usually on the recoil is not there. I searched the engine but can't seem to locate it. I believe it's an 8HP.

This came in not running so I cleaned the carb and after some adjusting, got it to run well. But my RPMS are fluctuating a couple hundred. I can't seem to get it to spec. It's not hunting I don't think. The variation takes place over a longer time period. Adjusting the carb or the throttle screw doesn't help with the fluctuation. I'm thinking that the throttle / governor spring is worn out. It's the one that wraps around the throttle lever as opposed to a spring connecting the throttle linkage to the governor. When at full throttle, it's not very tight. Could this be my issue?

[bgsengine]

model and spec are not always on a sticker on those engines, some (older models) will have numbers stamped in the blower housing just like Briggs did (many were "hidden" underneath the electric starter button box, others were stamped in the cooling fin heat shield) but your rpm fluctuation may just be a carburetion issue - especially if it is one of those with the metering rod in the idle passage (which may be why adjusting doesn't solve the issue) - if it is a carb with the metering rod and anyone has had carb apart before, if they didn't install air screw (in side of carb) properly they may have bent or damaged the metering rod, in which case you need a new carb.

[RoyM]

Hold your finger on the throttle shaft, if it smooths out you have a governor issue. If it stumbles it is starving for fuel. Is the throttle shaft sloppy in the bore?

[lefty]

I finally got a chance to take another look at it today. We got 18 inches of snow over the past couple of days.

So the throttle shaft does have a tiny bit of wiggle but I can't tell if it's a normal amount or if it's excessive.

Not sure if the carb has a metering rod. It does have a mixture screw in the bowl nut, as well as an adjustable idle mixture screw. While cleaning the carb, I removed both of those for cleaning and was careful when reinstalling. I started with 1.5 turns main screw and 1 turn on the idle. I was able to dial it in nicely but still have unstable RPMs. I didn't notice any damage during the process of cleaning and inspecting. Is the idle screw the rod to which you were referring? Or should be looking for the metering rod inside when the idle screw is removed?

I tried holding the throttle still when running and the engine did not smooth out. So it is the carburater based on Roy's assessment. It runs well for about 10 or 15 seconds then races up, sometimes as high as 3700+, unless I adjust the throttle screw down to 3200. But if I dial it up to about 3400, it will run smoothly for about 10 seconds then race up over 3700, which is scary.

The carb most closely resembles the series 3 on outdoorpowerinfo.com site and I have one that looks just like it in my box of miscellaneous carbs. Maybe I'll try that one out once I can varify it's a match for the machine. Still working on the engine model number. I checked under the starter button but nothing. I'll take another look tomorrow when I have some better light.

Thank you.

[bgsengine]

. I didn't notice any damage during the process of cleaning and inspecting. Is the idle screw the rod to which you were referring? Or should be looking for the metering rod inside when the idle screw is removed?

.

Was your idle screw kinda shorter , mostly threaded and longish taper to a sharp point, similar to HS screw? then its an idle screw, and no metering rod.. however if the "idle screw" has a longer smooth un-threaded shaft after the threads and end has a aggressive taper to a blunted point then it's an air mixture screw... this will have a metering rod in the idle mixture passage, with float removed from carb you shake carburetor up and down, should hear or feel the rattle as the metering rod knocks around.. if it doesnt your metering rod may be jammed, stuck, rusted, bent (They get bent if you install the air mixture screw in while the carb is upside down, float up, because metering rod will be sitting in front of the needle tip, older style aluminum needles would get smashed tips, newer style steel needles bent the metering rod, so they MUST be installed when the carb is oriented right side up!) Also the air adjust screw, where they are equipped, works the opposite of what you might normally expect , from initial 1-1/2 turns out, you turn screw OUT to LEAN the idle mixture (since that screw controls how much air flowing through idle mixing well to mix with fuel that is being controlled by the metering rod)

[lefty]

This is what it looks like.
Not sure why the image is so blurry but I think you can make out the shape.

[aj-allen]

You do not have a carb with the metering rod. The carbs with the metering rod were almost always 7HP and less.

[KE4AVB]

Lefty I gave up on Photobucket as they insisted on paid account with them. Almost did even get images downloaded that I had uploaded and deleted from my computer. It took two months of trying to finally get them back. I now IMGUR as my online host.

Which needle is that the idle mixture or the high speed mixture?

[lefty]

That's the idle from the side of the carb body.

I went through the carb again for a second cleaning and to investigate the components that BG suggested. I gave it another try and am having the same results, which I guess would be expected at this point. A couple of things I noticed.

Even if I put it to about 1/2-3/4 throttle, it will run there at about 2800-3000 RPM for about 10 to 15 seconds and then run away from me, upwards to 3700 before I throttle back down to idle. I also noticed that I don't see the governor arm trying to fight back at all. Could there be something wrong with the governor internally?

[38racing]

Is it a Tecumseh engine? If so check the bowl nut and make sure the tiny upper idle hole is clear. There is also an idle hole in the inside of vertical stack. Opposite the ball plug.