Snowblower Problem

I have a craftsman 7 HP Two Stage Track Drive Snow Thrower model #247.885570. If I am correct I believe it has a Tecumseh engine. My problem is when the snowblower hits a good amount of snow it just dies. Two years ago the snow blower had no problem tackling such snow. I drain the fuel and change the oil and plugs every year. I suspect it’s a problem with the Carburetor, but I have no clue how to clean, rebuild, or adjust it. Is there a website with info on this particular model, or can any of you offer any help. In my manual it shows that there is an idle mixture screw and a adjustment screw on the bottom of the carb bowl. Any assistance is greatly appreciated!!!

 

I believe 247 in the model # means MTD made it for Sears. It's not a Murray like mine, that would be #536.

If the motor has a model # beginning with 143 on it, then, yes it is a Tecumseh motor.

I'm sure T-man of this forum will be around to answer the carburetor question. I would try taking the bowl off and spraying it good with carburetor cleaner as well as cleaning the small holes and ports in the center bowl bolt.

 

Joe thanks for the help so far. I actually just said what they heck and went to sears and got a service kit. They gave me a tecumseh float so I assume its also a tucumseh motor, but I could be wrong. I replaced the float, float shaft, bowl gasket, bowl retainer, inlet needle, seat, spring clip, welch plug. The only two things I installed and have no clue how to adjust are the idle mixture screw, and the adjustment screw at the bottom of the bowl. At first the engine wouldn't turn over, but I adjusted the adjustment screw till it did and then tweaked it some more till the motor ran smoothly. I don't know how to correctly adjust this or the idle mixture screw. The blower works, but still has problems tackling a big pile of snow. Also for some reason I can only start it with the electric starter, I can't pull start it like I was able to do last year. Again any help would be greatly appreciated. Enjoy the snow!

 

Hello Faz Taz!

Start off by turning the low speed mixture screw (the one on the side of the carb) in all the way until it lightly bottoms out. Then back it out 1 1/2 turns.

Then set the speed control to highest speed and tighten the high speed mixture screw (the one under the bowl) until the engine begins to run badly and/or die. Then back it out while counting the turns until the engine begins to run rough. Divide the # of turns by two and tighten it back that many turns. You can fine tune from there if necessary.

 

Cheese thanks for the great advice.
When adjusting the low speed, should I also put the throttle into a lower setting, or leave it on the highest setting. Also I assure you want me to initially turn each screw clockwise and the back them out counterclockwise? Lastly when people refer to adjusting their blowers under full load what do they mean? Are they putting stress on the engine (snow blowing, resistance, etc) and then adjusting the mixture?? Again thanks guys for all the help. I really appreciate the friendliness of the members on this board.

 

FazTaz,

Joe and Cheese have already given you some EXCELLENT
advice. Nowadays....no matter how conscientious you are
about draining the fuel, changing the oil, etc....fuel stales
quickly and even a small amount of residual fuel left in the
carb passages can cause problems with starting, surging,
etc. Tecumseh developed, a couple of years ago, a GREAT
additive to fuel called "UltraFresh". As we say in the South,
"The woods are full" of different types of cleaners and
stabilizers, but I really like this one, and those I know who
have used it have had GREAT success with NO CARB problems.
Go to a Dealer and order part# 740063A, which is a blister
pack of (3) packs of this stuff. It's a granular type, like a
pack of sugar. Each pack will treat up to 2.5 gals of gas, and
you cannot overtreat, which is very possible with liquids.
It has a cleaning agent in it, and a stabilizer, and is just a
VERY GOOD product. I say this, objectively, and not just due
to my name. Try it and see for yourself.

Tcumcman

 

I took possesion of a used Troy Bilt 5HP (Tecumseh snowthrower last week just in time for another 6 inches of snow a day later. It hadn't been used in at least two seasons and had fuel (with stabilizer added) left in during this time. Of course, it wasn't about to start right up for me.

With a squirt of starter fluid, I could get the engine to turn over briefly, so I was getting spark. I removed the carb bowl and cleaned all parts as best I could then put it back together. Had no idea what adjustments to make to the various screws, so I just guessed. Got it going, but it ran very rough, backfired alot and stalled every time I put it under load. After fussing with the high speed and idle adjust screws (I know what they are now) I gave up shortly after dark.

Thankfully, I came across your small engine forum and late into the night read dozens of posts on carb servicing and adjustments. Even found a link to a tecumseh carb diagram. First thing in the AM, went out took the carb apart again, cleaned and cleared out the screw and hole which I missed the first time, put it back together and made the critical screw adjustments. A couple of minor tweaks once it was running and now the thing runs like a champ with plenty of power.

I have some additional maintenance to do (belts, oil, spark plug - any other suggestions?) but this got me through this storm.

Thanks to all for the helpful posts, particularly cheese, Tom_Bartco, Tcumcman and Joe_F. Very knowledgable and patient (answering the same questions over and over again).

B_Buckeye

 

Good for you! I just picked up a 6HP 26" Craftsman from Ebay (didn't sell so I offered the seller 100 bucks less than he was asking) that runs very well considering it is probably 30+ years old.

I have the good guys here on the forum to thank for the information that is provided. I try my best to contribute where I know the information

(Don't forget MikeMerritt, "Fish" and others that regularly contribute here).

 

Faz Taz...

Yes, set the throttle to idle when setting the low-speed mixture screw. And I do mean clockwise (when viewing the screw from the head) turning motion initially....as if to tighten it.

Adjusting a carb under full load would be as you assumed...tuning it to run best while the engine is working the hardest. If you adjust it properly....(the way I mentioned in the previous post)..you shouldn't have to worry about adjusting under a load.

Let us know how it goes!


B_Buckeye....I'm glad you were able to find the info here that you needed! Thank you for your appreciation!

 

While trying to fine tune the carb on my craftsman 7 HP Two Stage Track Drive Snow Thrower model #247.885570 with Tecumseh engine I started to have some serious problems. As per the advice suggested by cheese I adjusted the low speed mixture screw and then the adjustment screw at the bottom of the bowl. The snow blower was working fine. I put the cover back on and tried to start it up to see how it handled a full load. When I tried to start it the snow blower refused to start even after trying the electric start its still no go.

The blower just backfires and I see an occasional flame being shot out of the muffler. What can I do to get my thrower back in operation?? We will be getting close to 2 feet of snow so it needs to be working!!!! Thanks for any help!

 

Hello again FazTaz!

Sounds like either the engine is flooding, because of a float and/or neelde & seat issue, or your plug is fouled, or your flywheel key is sheared. Pull the plug, if it is wet and or carboned up, then change it. It wouldn't hurt to change it just to eliminate it anyway.

If it still doesn't run, check for execcisve fuel in the chamber. If the engine is getting too much fuel, inside the plug hole will look wet, the plug will get wet, and you'll smell gas.
Let me know what you find.

 

Cheese as always thanks for the help (you seriously know when to come through). How can I clean/remove the excess gas from the chamber. The plug does have carbon deposits on it, but it still produces a strong spark (should I replace it anways). Also can I check the flywheel key easily or do I have to really disassemble the unit?

 

FazTaz,

Dump ALL the fuel in the tank and carb out. You can drain
the float bowl by simply loosening the adjustment screw.
Snowblowers are notorious for "water in the fuel" OR....
ice/snow collects around the fuel tank/fuel cap and prevents
the tank from venting so fuel can flow thru the system. Be
sure the tank cap is NOT COVERED with ice/snow. Fresh fuel
and a new plug might just be the "TRICK"...HOPE SO !! Looks
like one of the biggest snows of the year for the midwest and
northeast. You guys....KEEP IT !!!

Tcumcman
South Carolina

 

Thanks guys again for all the help, it just doesn't make sense, because I tried to restart it 15 min after I made the adjustments according to cheese (that worked). Im gonna change the plug, gas, and anything else? Also should I try some type of fuel additive or just use regular grade fuel??

 

I know how you feel. My 1965 6HP 26" "Oldie Goldie" Craftsman as T-man puts it ( ) is out of service now waiting for a new recoil spring . I should have left the hokey wood handle on there till after the season.

It's ok though as I have backup machines and electric power shovels (2 of 'em) as backup! LOL. The blower was a niciety to myself this year

I believe you have a wasted carburetor float/needle and seat. As mentioned, I would eliminate the plug as a cause. Change it. I change my plugs once a season on small equipment, for $1.50 at jobber wholesale price for me, I don't gamble. See if it fires up. If it runs rough, you may have to dismantle the carburetor to see if you can clean it or perhaps replace the expendable parts in it.


T-man and Cheese: Oldie Goldie is definitely a 1965 model. I got confirmation from Tom at Tecumseh Tech Services. He found a copy of an old Sears handbook he is sending me which shows that it's a 1960's model .

 

Ok guys here is the scoop. The snow has begun and still no go. I dismanteled the card, made sure everything was fine, checked the spacing of the float, made sure the needle was fine, etc. etc. I drained all the gas from the pipes, carb, removed the old spark plug and left the hole open for any gas to evaporate. I replaced the plug with a properly gapped (.025”) one, and put a fresh tank of 86 octane gas. The unit will backfire when only when the choke it on, and it will not run at all. I can see a flame coming out of the muffler, but it wont turn over. Where do I go from here?? Any help would be greatly appreciated. I need to get this bad boy up and running before Im covered in 2 feet of snow!

 

FazTaz,

As some earlier posts have suggested, the flywheel key
could be sheared....a valve could be sticking in the valve
guide....?? Do you have a compression tester ?? If so....
what reading do you get ?? Try disconnecting the green
grounding wire connected to back of the coil, and try starting
this way. If this solves the problem, then you will not be able
to cut the engine off unless you ground out the plug. A
safety switch or grounding problem could be shorting out
the ignition system and giving you intermittent fire ?? This
might require some more in-depth analysis, but HOPE these
ideas will prove successful !!!

Tcumcman

 

I removed the spark plug to make sure there was good spark. There is a spark between the spark plug cable/wire and my finger, is this indicative of a faulty wire, or does it just trying to find a ground (me?)

 

Ok so 4” so far and counting. I took the carb off again for the 4th time, rechecked all the specs, 11/64” for the float, even pressure checked the needle/seat by blowing into the gas line. It is a good seal. Plug has been changes, the gap has been checked to make sure its .03 as per the manual Even took out the plug tipped the unit over and pulled the starter cord a couple times to remove any excess fluid in the combustion chamber. The unit will still backfire producing a blue flame out of the exhaust/muffler, but will not turn over. Any more suggestions? Gonna check the flywheel key as soon as I figure out how to?

 

FazTaz,

I'm "assuming" your engine is new enough that it has
solid state ignition....Flywheel spins in a clockwise rotation.
At top dead center, flywheel magnet will have just passed
the 2-legs of the coil. As you look at it, the magnet on the
flywheel should be just to the right of the coil. If you find
the magnet ANYWHERE ELSE....key is sheared. Usually,
the magnet will be at, or near, the center of the coil legs
when the key is cut. To remove the flywheel, remove the
rewind starter cup, put flywheel nut back on crank threads
and run it to flush with the top of the crankshaft. While
prying up/out on the flywheel from underneath with a large
screwdriver, or small prybar, strike the nut with a brass
hammer, or regular hammer, paying attention to strike the
nut squarely in the center. A knock-off tool works BEST,
but this will do in a pinch. Hitting too much & too hard this
way can damage the crank threads OR break off the end
of the crank....SO...BE CAREFUL !!

Tcumcman

 

To me it does sound like a a sheared flywheel key. This would cause it to ignite the fuel mixture while the exhaust valve is open causing the blue flame coming out the muffler. Just incase you don't know, an easy way to remove the flywheel is for one person to have a screwdriver under each side of it and pry up while you take a hammer and hit the top of the crankshaft. Also, make sure to back the nut to where the top of the nut is even with the top of the crankshaft. This will protect the threads from being messed up.

Since I live in southern Louisiana I can only imagine what 2 feet of snow is like.

 

Again guys thanks for the help, Im trying to find out the diagram to remove the housing to get to the flywheel. Tcumcman the blower is about 7 years old. I was also thinking before I go through all the hastle of removing the flywheel do you think maybe the plastic safety key, or any of the grounds are possibly loose (Im not sure how to check). I remember hearing that if the key is not in or the connection is messed up then the unit will not turn over. From my understanding they key blocks the ground connection for the engine block?? Anyways limme know what you all think. Again your assistance and generosity in spilling out information is most appreciated.

Im about 6" of snow and still no blower?? I guess Im gonna be shoveling tomorrow

 

Sears.com and then "parts". Plug in your model # and you'll get an exploded view of the unit and engine.

 

Given what has been done so far I would check the valves for one frozen in its guide probably exahust. The reason I say this is carbs adjustments can lean out an engine causing a lot of heat and this is just what can cause a valve to freeze if its on the verge of hanging. Throwing fire is a symptom of a sheared key but something has to shear a key.....Mike

 

Mike thanks for the tip, how would I go about doing this?
?

 

Ok removed the the flywheel cover now where can I locate the flywheel key? All the diagrams I have just so a picture of the key, not where it is located. I spun the flywheel, the magnets don't rub against the laminations on the solid state ignition assembly. There is spark in the plug when the starter is turned. So basically where is the flywheel located, how do I replace it, and what does it do exactly?? Thanks again guys

Almost 2 feet and still no damn blower.

 

Hey guys if the flywheel key is what sits partially in the crankshaft to keep the flywheel connected, then it looks intact to me. I don't see any reason for the flywheel to slip from the crankshaft.

So I've checked
spark plug
flywheel key
carb
cleaned out gas
filled with fresh tank


I seriously am dumbfounded. Could incorrect grounds cause this problem, or a bad sparkplug coil?? Im just fishing for ideas

 

Taz...Take the plug out, push your thumb over the plug hole to seal it off, then turn the engine. Do you feel any pressure at any point when you turn the engine over? If not, Pull the head off and fix your stuck valve. Mike mentioned this, and I believe he's on the right track.

 

I check the compression, its fine, when I plug the hole and turn the engine over there is pressure. I removed the valve cover, cleaned the valves, piston head, etc. Any more suggestions as to what the problem could be??

 

Faz,

You mention at the beginning of this thread that you removed the carb cover. When you put it back on, did you perhaps pinch the ignition wire or the primer line? 'lint.

 

FazTaz,

You're giving it the "All American Try"...no doubt, but....you're
missing something that will probably turn out to be a simple fix.
Did you disconnect the green grounding wire on the back of the
ignition coil and try starting it that way as I suggested earlier.
The 'ole "finger over the spark plug hole" method is a way of
checking for some compression, but certainly NOT the fool
proof way. The valve can be sticking near being seated, but
not seated. Even with a sticking valve, there will be some
pressure thru the plug hole. That there is "fire" out the muffler
STILL INDICATES that this problem is ignition, OR valve related.
The latter, of course, being the more difficult to correct. FazTaz,
at this point, and IF the green ignition kill wire DOES NOT FIX....
I'd suggest taking to a reputable shop that's familiar with
snow equipment and let them troubleshoot for you. From your
comments, it seems you are very inexperienced, though, your
determination is awe inspiring. I'd hoped by now that some
of us would have come up with a "CURE" for you, particularly
given, the amount of snowfall you're contending with. Keep us
posted....and, GOOD LUCK !!!

Tcumcman

 

Hey all first off thanks for your help. The willingness of this board to help a fellow member is simply amazing. Everyone one is willing to help out and my questions are answered in less than an hour. Well I finally was able to get the stupid thing started. I checked the unit for compression and did feel a good push against my thumb. However I decided to take the unit apart anyways and clean out the valves and piston head with some carb cleaner, sandpaper, and cloth. The valves, cylinder head, and piston head had a great deal of carbon deposit. As I removed the cover I noticed that the gasket was cracked and by the looks of things had been cracked for a while because there was significant carbon deposits from the mixture leaving through the hole in the gasket. Anyways since Sears and every other parts store was closed today I decided to just try to fix the gasket myself temporarily. (My parents were trying to shovel the 2 feet of snow that had accumulated on the driveway, and I’d rather they move the blower and I shovel, rather than the 3 of us all blowing our backs). I gleaned up the gasket, and then used a couple layers of heavy duty electrical tape to fill up the gap that the gasket had. The motor then started up and ran smooth, cleaning up the other 3 quarters of the driveway that had yet to be cleared.

The snow was so high that the auger was just able to snatch it all up. I could only run the unit at the slowest gear, otherwise it would just die. Is this normal?

Anyways like you said Tcumcman I’m only 23 and very inexperienced when it comes to small engines. I currently in school, and have no engineering background, but love to take apart odds and ends and put them back together. I do basic maintenance on all the cars and small engines, like changing fluids, filters, etc, but this is the first motor I have actually taken apart and the first carb I have rebuilt (with the help of this board of course).

Thanks to all those who have helped and Special thanks to Tcumcman and Cheese for the help you have given with this and all past problems and questions. Any recommendations as to the cheapest place to get a new gasket, and I would also like to add a light to the unit?

Blizzard of 2003: Problem averted!
Thanks again
- Faisal

============
Moderator Notes:

Hello: Faisal

Glad you where finally able to get the machinery running with the professional advice offered. Thanks for posting back the final results too. Much appreciated.

This entire thread has been merged together to allow all the questions and replies to be in one entire question.

TIP: To All Forum Readers.

Whenever any question requires additional information or there is a need to ask additional questions on the same equipment, the member starting the new thread {asking the original question} should always use the REPLY button and continue to do so until the problem is solved with the machine.

Doing so allows all the threads to remain in the same question.

Thanks,
Web Site Host and Small Engine Forum Moderator.
Tom_B

 

Good Job Taz!

I'm glad we were able to help, although a head gasket wasn't expected. I suspect you had carbon causing a valve to let compression out, and removed it when you cleaned it up. The thumb-over-the-plug hole trick is definitely not a scientific way of checking things, but it will tell you if the valve is stuck wide open. Most DIY'ers don't have compression gagues.

Any local small engine shop should have a head gasket for your engine. It won't cost much....maybe $5.00.

 

FazTaz,

Sounds like you've determined the "root" of your problem.
As normal with these small engines....it's usually something
simple....it's getting to that point that usually takes time &
effort. As Cheese indicated, a head gasket can be purchased
from a local Tecumseh Dealership OR on-line. The part number
you need is 36453. This is NOT one of the more popular
gaskets, and as such, the local Dealer may have to order for
you anyway. You might want to call around and give this
part number to see if anyone has in stock possibly. Otherwise,
you might just order on-line and have it shipped to you. It
might arrive to you just as quickly as having a Dealer order
it for you. Glad to hear you got it going. Electrical tape to
plug a head gasket....that's one I hadn't heard of before.
Bet it smelled funky....??

Tcumcman

 

Cheese and Tc its funny how such a stupid thing could cause such a big problem. Your right about the gasket cover, the number is 36453, and so far of the 3 people I’ve checked no one stocks it. The electrical tape surprisingly hasn’t started to smell/burn yet. Since you guys are the experts I’ve noticed that there is an electrical cord/terminal that could be attached to a light source. Do you know where I can purchase such a light? Or which model/make/wattage I need? Lastly there was about 2.5 feet of powder. The snow blower had to be run at the slowest speed setting (1) and every 15 feet or so the engine would start to die, so I had to release the auger clutches and let the engine recover before I started to plow again. Is this normal under such conditions for a 7HP blower?

 

When you get the head back off to replace the gasket, check your valves really well to be sure they aren't burnt or not seating well. Then, if all is good there, the new head gasket may be all it takes to fix your low-power problem. The gasket with elec. tape on it almost HAS to be letting compression out. The gasket has to be fixed before any further diagnosis can be done...if needed. If it still doesn't run right, we'll go from there.

 

Cheese the valves, along with the piston head, and the entire chamber were chared. I used a 200 grit sandpaper and cleaned off the piston head, valves, and chamber. Then used Carb cleaner and a rag to bring it to a good shine (little or no deposits). Im sure your right about the tape, I could see some smoke coming out from the back of the engine, Im sure its exiting from the tape. Anyways I'll replace the gasket.

Any suggestions about the light??

Also is it safe to use Sears brand fuel preserver or is there another locally available one I can get?

 

A regular fog/utility light should work fine. Get one that takes a regular 1156 bulb, not one of those halogen or high powered lights. Just hook the wire to the positive on the light, and ground the negative from the light to the frame.

Probably any stabilizer would be fine to use.