Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Just inherited my fathers old snow blower which he hadn't used in a couple of years.    Flushed the gas, added new.  started right up but the unit didnt drive forward.    Like an idiot I tipped it on its side to examine the pressure disc and didnt notice the oil pouring out the carb for a few minutes.     Wouldn't start after that.   Pulled the old spark plug to check for oil in the cylinder.   none came out when i pulled the cord.   Put in new spark plug,  drained old oil and refilled with 5w-30 and it fired right up but will only run on 3/4 choke and full throttle.   TYried adjusting screw on bottom of carb but it just kept stalling out.    Is this because the oil that ran through the carb? Any suggestions would be great.     Also Does anyone have a diagram of the carb?   It may be missing an air filter,   Im obviously not too familiar with these thing or I never would have tipped it on its side.

Thanks matt 

Here's a link to the Tecumseh Technicians Handbook including the HM80. Carbs start on page 11. Normally snowblowers do not have air filters. Has something to do with icing I think, plus they are not really needed since it isn't too dusty in winter.

http://www.cpdonline.com/692509.pdf

Cheers

the  oil in the carb most likely has nothing to do with it.the screw you adjusted on the bottom of the float bowl(carb) is the high speed needle  mixture adjustment screw..the mixture screw is initially set at 1 1/2 turns out from litely bottomed.the screw itself is turned into the high speed jet.this jet can be turned completely out of the carb but the fuel has to be shut off or run empty because the jet  keeps the float bowl mounted to the bottom of the carb.the jet is brass and has very small orafices in it for the gas to go thru at full speed.the engine not running without the choke on is an indication you have a fuel restriction somewhere.the jet is an easy place to start  and by doing so will also be able to clean the fuel bowl out.if you decide to remove the bowl mark a scribe line on the bowl so you can index it to the carb body when you put it back on.some bowls have to be positioned in relationship to the float.if the bowl is clean and you clean the jet orafices (use a small fine wire and carb cleaner) before putting the bowl back on turn the gas on slightly to see if fuel is at least getting to the carb past the needle and seat.once back together try a double or triple strenght dose of sea foam with fresh gas and see if it doesn't help.i have a 1986 hm80 i bought new and the carb is the only thing i've had to tinker with .mine was getting finacky at full speed because of age and lack of use also. the initial low speed mixture screw is 1 turn out from bottom and the high speed is 1 1/2 turns out.the low speed mixture is on the side horizontally and above the carb throat .both low and high speed makes up the total mixture at high speed.you will have the adjustment right when you can move the throttle sharply from curb idle speed to high speed when fully warm and there is no stumble(lean condition)or loading up(rich condition) as it reaches it's set rpm.best of luck.

I've learned through hard experience the needle valve has a hole that gets clogged.  Once it does, it just won't work right.  I've had good luck dropping the entire needle valve assembly from the carb, and running a fine wire through the hole in the needle valve.  Doing it this way avoids re-setting the needle valve.

Last summer, I just unscrewed the needle valve and cleaned it all because of some dirt.  The post above mine has the correct procedure for setting it.  The only thing before you set the needle valve, let it warm up for 15 minutes.  If you google, you can find even more detailed procedures for resetting the needle valve if you google it.  I thought I had them here on my HD, but it appears I lost them.

The carburetor is a little fussy from that standpoint, but generally, it gets you through a couple winters before you need to clean it.