8 hp Tecumseh carb. adjust
#1
12-09-09, 02:55 AM
8 hp Tecumseh carb. adjust
Hi, I'm new to this forum and would like to get started by asking: How do I properly adjust the carb on my 8 hp Tecumseh snow blower engine? It has what appears to be a small screw at the bowl end and another one on the body. (probably high and low idle). Please tell me which is which and what is the starting adjustment. I played with these for hours and can not maintain a steady idle on high. It also seems to want to rev very high. Thanks!!! Frank
#2
12-09-09, 04:08 AM
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Hello
Welcome,
You find allot help in here. Great people and people that want to help and know their buisness.
The Needle on top is the low idle. The one on the bottom of the bowl is the high idle and or power end of the engine.
The rule of thumb and the book does say on this Carb one turn out from seated position. Becareful when seating the needle not over tighten it.
I take a grease pencil and or a permanent marker and place a mark on one of the flats and then go open one turn to it stops on the mark you made. This is a good reference point from there. this a visual practice for me and it works. You can just look at it and turn to, but if you have no exprience your eye balls could lose the starting point for you. Crank it bakc in and try again. Even after years of doing it my eye have played tricks.
The bottom on or high idle same thing. The book says 1 1/2 on this one. But one gets you in the ball park.
Most Carbs this is a good thimb rule all the way in and 1 turn out.
Then you can try starting it and adjust it. Sart the adjustment with the idle screw first. Allow it to warm up as you are making adjustments.
Adjust the Carb while it is running in the open diresction first until it starts to run rough but not stall. A normal engine will reve up and then start to choke at this piont. If it does slowly close the needle unti it runs high and smooths out. That is a good position then on the idle screw. It should idle nice and smooth. If not play with the idle screw until it sounds good. But as you close and open too far the engine will talk to you and let you know you are too lean and or too rich but cutting off the Sweet spot is between the two.
Once the idle is done it is time for the High needle. You will pratice same things as the L Needle. Slowly start increasing the RPMS and listen the engine will talk and act maybe crappy. As you increase RPMS and then slowly adjust and move the neelde once again in the open direction and same thing will happen as it did adjusting the L needle.
You are looking for that sweet spot once again, then drop the speed fast and see if she idles and then reve it up and see if she goes quick and does not choke out on you.
That should do it for you.
I hope this helps and does not confuse you.
Have a great Day
Henry
You find allot help in here. Great people and people that want to help and know their buisness.
The Needle on top is the low idle. The one on the bottom of the bowl is the high idle and or power end of the engine.
The rule of thumb and the book does say on this Carb one turn out from seated position. Becareful when seating the needle not over tighten it.
I take a grease pencil and or a permanent marker and place a mark on one of the flats and then go open one turn to it stops on the mark you made. This is a good reference point from there. this a visual practice for me and it works. You can just look at it and turn to, but if you have no exprience your eye balls could lose the starting point for you. Crank it bakc in and try again. Even after years of doing it my eye have played tricks.
The bottom on or high idle same thing. The book says 1 1/2 on this one. But one gets you in the ball park.
Most Carbs this is a good thimb rule all the way in and 1 turn out.
Then you can try starting it and adjust it. Sart the adjustment with the idle screw first. Allow it to warm up as you are making adjustments.
Adjust the Carb while it is running in the open diresction first until it starts to run rough but not stall. A normal engine will reve up and then start to choke at this piont. If it does slowly close the needle unti it runs high and smooths out. That is a good position then on the idle screw. It should idle nice and smooth. If not play with the idle screw until it sounds good. But as you close and open too far the engine will talk to you and let you know you are too lean and or too rich but cutting off the Sweet spot is between the two.
Once the idle is done it is time for the High needle. You will pratice same things as the L Needle. Slowly start increasing the RPMS and listen the engine will talk and act maybe crappy. As you increase RPMS and then slowly adjust and move the neelde once again in the open direction and same thing will happen as it did adjusting the L needle.
You are looking for that sweet spot once again, then drop the speed fast and see if she idles and then reve it up and see if she goes quick and does not choke out on you.
That should do it for you.
I hope this helps and does not confuse you.
Have a great Day
Henry
