I have an older Snowblower with the HMSK80 Engine. Currently it will only run with the choke fully closed.
I have done the following.
1. Replaced the carburetor
2. Checked Fuel Line, gas tank fuel flowed as expected.
3. Replaced the Fuel
4. Cleaned the Spark Plug
5. Put on new Primer Bulb
When it's running (With Choke Fully closed) I do get a little back fire.
When I move the choke even partially open the engine stalls out and quits.
Any ideas on what else to check?
Thanks,
Rog
#2
Boudreaux In Eunice La.
A couple questions for you ..........
1...... Was your old carb doing the same thing before you put a new carb on it ????
2...... Did the new carb come with the mounting gaskets.. Or you used the original gaskets ????
3...... Did you clean the tank and check fuel lines BEFORE installing the new carb ???? If not then you might have gotten junk in the carb and started the problem over again..... I usually just clean the carb that comes with the Generators we have down here... We have no need for snow stuff....... Weeeelllll last winter we got close to it though LOL....
Try this ...... when it's running spray some WD-40 around the engine block area and where the carb bolts to and see if it dies out or changes in the way it runs ........... If so then there lies your issue ........ An air leak
If you have to run your engine on choke that means you have a air leak somewhere or you are not getting enough fuel to your carb .......
Just because you had good fuel flow from your lines doesn't mean they are in good shape.... They can breakdown inside from the impulse pressure from the engine and a liner inside the line will flap and slow the flow down ......
BTW that aftermarket carb you bought might not be up to par... I have seen good and bad ones...... I put OEM carbs on if I cannot rekit the one that's on the unit and get it to run right ...........
If it was me I would take the old carb and clean and rebuild it with part number 631021B. I rebuild at least one a week and this is the procedure I use. Make sure that you clean the idle jet on the side of the carb, if it has one, under the plastic cap. This is most often plugged. [FONT="][FONT="]Needle and seat replacement.[/FONT][/FONT] [FONT="][FONT="][/FONT]
[/FONT] [FONT="][FONT="]Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.[/FONT][/FONT] [FONT="][FONT="][/FONT]
[/FONT] [FONT="][FONT="]I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.[/FONT][/FONT] [FONT="][FONT="][/FONT]
[/FONT] [FONT="][FONT="]With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. Next check to make sure that the float does not have any liquid in it. If it does, replace. If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.[/FONT][/FONT] [FONT="][FONT="][/FONT]
[/FONT] [FONT="][FONT="]PS: On the side of some Tecumseh carbs you will find a plastic cover. Under this cover will be an idle jet. Remove it and check to see that the jet is open both horizontally and vertically. You should be able to push the old float needle wire through the vertical opening.[/FONT][/FONT]
