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Honda HS621 SNowblower overspeeds


JETMECH727's Avatar
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10-27-04, 04:38 PM   #1  
Honda HS621 SNowblower overspeeds

Hello,

I have a Snowblower that has not run for over 8 years. I just got it fired up today. However I have a problem and no manual or drawings to go by. The engine runs well in full choke and wide open throttle. As I move the choke to a more open position the engine just screams and backfires. As it gets closer to the full open position it just shuts off. I dont seem to have any throttle control. Theres a throttle return spring thats not hooked up. I dont know where it goes. One side is on an arm hoked up to the engine case that also has the governor rod attached to it. The engine still shuts down If I try and modulate the throttle plate manualy as well. Wondering if anyone has any expierience with this type of setup.

Thanks

 
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10-27-04, 05:59 PM   #2  
JETMECH727,

I would most certainly consider an intake leak. The air is coming in after the throttle plate and mixing with the (choked) low pressure gas spray from the jet. The small govoner spring, I would think, could not cause this condition however, Cheese and Azis could most certainly confirm this!

Best Of Luck!
Dave

 
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10-27-04, 07:38 PM   #3  
Azis
Check to see if your throttle plate inside the throat is actually moving. Sounds like it may be stuck open letting you use the choke valve as a throttle valve.
I am not familiar with with snowblowers and you did not mention what size engine, still the carb should be pretty simple, you may be able to see the throttle valve with the air breather off.

 
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10-28-04, 07:46 AM   #4  
The throttle plate moves just fine. The governor is springloading it wide open. Im not sure How it all hooks up to the metal lever on the engine case. As I said, I have a throttle return spring thats not hooked up and dont know where it goes. As I manually close the throttle plate via the governor rod, I can feel a vibration in the rod as the plate reaches closed. I have no Idea how throttle operation is done on these motors. Its a 6HP unit. It starts fine and runs fine in the closed throttle position. Everything starts to go for a dump once that choke goes to full open. It red lines at half open then shuts off at full open. Any idea where I can find an exploded drwing of this unit?

Thanks

 
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10-28-04, 09:33 AM   #5  
Azis
You will need the model # off the engine, honda's can be a pain to find, you can get the owner/operator manual here http://www.hondapowerequipment.com/own.htm
Other manuals are available too but some you must purchase. I think I have used one of the operator manuals tho and recall seing some illustration of the govenor/throttle linkage adjustment so it may help.

Sorry but bout all I got for ya

 
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10-28-04, 12:24 PM   #6  
No problem Thanks for the help anyway. If I get Pi!#ed off enough Ill throw on a Chevy 350! I know how to adjust that damn thing. And Ill clear snow for the neighbourhood then.

Thanks again

 
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10-28-04, 01:58 PM   #7  
I was just out fiddling with the damn thing. Basically it runs hard and strong at about 1/3 choke towards the full open position. Beyond that and including full open it slows down and shuts off. There is also only one metering screw on the carburator. Right next to where it mounts to the head so at the throttle blade position. I turnrd it in and out and nothing changed. Its been years since ive messed around with carbs but tht sounds troublesome to me. Any more ideas? It starts instantly without hesitation in the choked position. I just need to leave it there.

Thanks

 
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10-28-04, 03:29 PM   #8  
Azis
Are you sure you can see the throttle valve (plate) inside the throat move? The linkage and shaft on top of the carb may move but if it breaks like where the plate screws on to the shaft, the linkage and shaft will appear to move normally although not actually move the plate inside.....
Otherwise if it dies when you attempt to open the choke, you have a fuel restriction most likely in the carb. A good cleaning should get it, I dont think there is much to kit on those.

 
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10-28-04, 04:34 PM   #9  
Throttle plate is moving. Im leaning toward a fuel restriction. Most likely gummed yp. But where? I pulled the metering screw and it was clean. Then again It had no effect on the operation of the engine. The fuel in the little cup beside the fuel bowl had a greasy substance in it. Probably gummed up fuel. So did the bowl. I cleaned that. Initially the engine would run only if I poured fuel down the throat of the carb. Once I cleaned the bowls it ran off the fuel tank. But where else would a jam up occur? It stands to reason that its fuel related. I mean at WOT theres a huge air demand which its meeting but not enough fuel to balance it out.

Thanks

 
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10-29-04, 01:08 AM   #10  
I agree with Azis...you need a carb cleaning. Not just a spry cleaning, but a disassembly and dipped in chemdip or similar solution. There are several tiny passages in the carb that can be restricted.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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10-29-04, 05:46 PM   #11  
Just wondering if Icould use a general engine degreaser to soak the carb in. Or do you have a product in mind that would best suit the job.

Thanks

 
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10-30-04, 12:57 AM   #12  
Nope, there are products designed specifically for this purpose. Napa has a version, Chemdip and Berryman also make the product. You can get it at an auto parts place in gallon pails.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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10-30-04, 10:52 AM   #13  
Azis
Be careful not to soak any plastic pieces that can not be removed, those cleaners will clean them gone

 
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11-05-04, 05:06 AM   #14  
Thanks for the help everyone. Soaked the carb over night. Engine is running great now. Guess it was just gummed up.

Thanks again

 
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11-05-04, 06:41 PM   #15  
Glad we could help!


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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