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Snow King 5hp-new carb-starts great, idles fine, quits under throttle


minidon's Avatar
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12-09-07, 06:33 PM   #1  
Snow King 5hp-new carb-starts great, idles fine, quits under throttle

What a great site! Thanks for doing this guys. I have a '95 MTD snowblower w/Tecumseh HSK50. Was running great this season until this week when it suddenly quit under load. I never got it started again. I'd had the carb cleaned and serviced several times over the years, and finally decided to just get a rebuild kit--but the rebuild kit the dealer matched for me wasn't the right one. It appears my carb is an emission carb, the kit was for adjustables. They couldn't find the right one, so I ended up just getting a new carb--identical to the one I had (emission). Put it on, it starts great, runs nice and smooth at idle, but won't accelerate at all, just coughs and dies at the least touch of the throttle. Any suggestions? Thanks!

 
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12-10-07, 12:25 AM   #2  
Sure sounds like a fuel problem.....still. Check the valve clearances and make sure the exhaust is not restricted. I would think replacing the carb would eliminate it as a problem, but it does still sound like a carb problem. Are you certain that it's the right carb number for that engine? Was it exactly like you old one? Are there screw holes at the end of the carb where the air enter it? If so, are there screws in them? (one of these can be a passage that must be blocked on some carbs).


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12-10-07, 02:17 AM   #3  
Post back with the complete engine ID numbers as well as the part number you purchased for the new carburetor. I can confirm if you got the correct replacement carb. Being a '95 MY this should be an adjustable jet carb, not a fixed jet.

 
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12-10-07, 10:47 PM   #4  
Thanks for the replies. Here's the info: Engine ID is HSSK50-67376P with a (H) on the label. DOM is 5178 0. The replacement carb is P/N 640084B. It's exactly like the one I took off. No adjustment screws. Cheese, the only screw holes in the air intake end are those for the choke linkage, unless you mean other screw holes, which I don't see.

 
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12-13-07, 03:07 AM   #5  
OK, here's the deal. Originally, from the factory, this engine had an adjustable carburetor, Tecumseh part number 632107A but since the federal government has a say in the matter, Tecumseh can no longer manufacture adjustable jet carbs. But, if you find the right small engine dealer you can find this part. It's not illegal to sell them, they just can't be made. Since you have a new carburetor already (and it is the correct replacement for your engine) and probably don't want to spend any more on this thrower then remove the bowl nut (main jet) and clean out the tiny holes in such (four total) but do not bore them oversize in cleaning them out. One thing to bear in mind is that you may not have a carburetor issue, you could have a weak ignition issue. Although that would be rare it is possible.

 
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12-14-07, 04:28 PM   #6  
Thanks Puey--here's what's happened. Since the carb is brand new, I decided to go through several pages of posts on this forum and jot down as many suggestions as I could find that I hadn't tried, then just go through the list. One post about a broken plug wire stuck with me, so I checked the plug (new from a tune up last fall), and the plug was badly fouled with carbon. So I cleaned it, put it back in, fired it up and sure enough it throttled up just like new. Kinda threw me because I figured since it started fine and idled fine it had spark. But I guess it had just enough carbon on the tips that the extra gas on throttle up must have snuffed out what spark there was or something. So now it's running great--except it's overspeeding slightly, but I just don't give it full throttle and it does the job. Thanks for your help!

 
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07-31-09, 05:18 AM   #7  
Idles fine will not throttle up

Apparently almost any of the systems in small engines can cause this lack of high throttle problem. After reading this thread and a hundred others for my older Tecumseh 10hp lawn tractor that would not start (no spark) until I changed out the points and condenser . I got it to idle fine but it would not throttle up. Anytime the throttle was raised, it would die immediately. I did everything from rinsing out the gas tank, cleaning the carb, adding a fuel filter, and a new plug, someone said it might be firing too early. Even though, I had set the gap at .030, I rechecked where in the cycle the points were opening opening at that gap setting. Sure enough, they were opening at probably 1 or 2 degrees before top dead center. I reset the points to exactly TDC and it fired right up and ran fine. The gap at that settling was now .020. Maybe on the engine made it necessary to lower the gap. Hope this helps.

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07-31-09, 11:54 PM   #8  
Actually, .020 should be the recommended setting. .030 is the spark plug gap.


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