tecumseh carb

[EASLOOP]

I have a very old Tecumseh engine on a ?outboard leg. Whole thing called a MAC-3. I have had a spark problem which is now solved. The engine now starts and after a second or so stops so I expect a fuel problem. Under the float chamber there is a central screw which I presume is for draining purposes but adjacent to that screw is anothe'screw' on a spring that allows it to be pushed up with my finger so that fuel pours down my sleeve. Does anyone know anything about these engines such as what these two screws are for?
Looking forward to replies

John

 

[Bill1]

I think the "screw with a spring" will be for allowing air out of the float chamber and hence fuel in before starting the engine. It's a device found on many older petrol engines including seagull outboards. Hold it down until fuel flows out of the float chamber then start the engine.
Your quite right the other screw will be for draining the float chamber.
BTW we called this "tickling" the engine.
Bill

 

[andy_wilson]

Tickler

Think also the tickler lifts the float and allows it to over fill to get the engine going. Once started the choke will look after things until it warms up (or not in your case).

Sometimes one of these screws may be an aid to setting float level. As your motor won't stay running, try adjusting in increments, up first, then back if no better, to see if you can coax it into life.

 

[chippie]

If fuel is coming out of that spring loaded screw, the fuel is getting to the carb and not the motor. Check the vent hole in the fuel tank cap, and then check all the orifices in the carb by blowing through with compressed air.
Make sure there is no air leak between carb and engine/reedvalves. These are simple motors, once you get the feel for them they are easy to maintain. Is it the points ignition model, or the later electronic one? If it is points, take the flywheel off and clean them and check the gap. The electronic model has a spacer between the flywheel and shaft, the lugs in the spacer sometimes come off and upset the timing. <span style="color:blue"> </span> ( I dont think it is this in your case)

 

[the_wanderer]

Had the same problem with my Tecumseh engine on my lawnmower. Probably the same unit. As it is a simple carb with what I can make out to only have one jet, (somebody please correct me if I am wrong), there was a lump of crud blocking this jet which is just above the central screw at the bottom of the float chamber. Clearing it solved the problem. The "tickler" is also handy for draining water from the float chamber which will also cause the same symptoms you describe. Whilst on this subject, check the petrol tank as condensation can build up and eventually deposit a fair amount of water. If the breather hole in the tank is open to the weather this can also cause an ingress of water. Cover it up.

Regards.

Alan.