starting a hand start A

[alvan]

I have a 37 unstyled A. It has a complete rebuilt mag new complete rebuilt carburetor new wires new plugs and can not get it to start by hand. I can pull start it and it runs like a top. Any suggestions please. Thanks

 

[John T]

Start timing is pretty important on those hand crankers. I set mine dead on TDC, too late and shes harder to start but too fast she kicks back. You mention a rebuilt mag but the impulse spring and mechanism must be in top shape. If the spring is weak the start spark is weak although she can be pull started easily. Mine like to be hand started with the throttle at a very slow idle. Don't overchoke and wet gas foul the plugs. If my choke is nearly full Id only crank it a couple times then open it up.

After cranking are the plugs wet or dry????

John T

 

[alvan]

I bought the mag from a guy that is all he does. Its a nice mag everything inside and out is new. Timing might be off how the best way to time them.

 

[Bob]

"how the best way to time them."

Just a GUESS, but having the impulse "trip" @ "LH Impulse" will get you pretty close!

 

[John T]

Bob has you covered EXACTLY (Mag trips when flywheels Left hand Impulse passes by the flat mark on the tractors side at 3 o clock). The method I use is to remove the plugs and rotate the flywheel to observe and listen when the mag trips which should be at LHI at 3 o clock. That's when the left cylinder is at TDC. To adjust it loosen the mags mount bolts and rotate it forward CW to retard or backwards CCW to advance. Too fast she kicks back too slow harder to start.

John T

 

[John T]

Yo Bob, you call it "Just a GUESS". (Yeah right) You rascal you know that's right lol

Take care Bob

John T

 

[barry county]

Does the magneto impulse make a nice sharp "SNAP" when rotating by hand? You may need to add a thicker gasket between the mag and gov. They need room to move...

 

[rick deere]

Ive got a 37 A , I just went out and did what you said worked great,but the mag is tilted all the way back, but starts good now, I also have another 37A and the mag clicks at 3 as well but the mag is centered,both start good but why the differance in the angles of the mags results are the same.Thanks Rick

 

[John T]

Sounds like the Lag Angle adjustment on the rear is off. When all was new and all was right if the lag angle was set correct the mag was pretty well straight up n down when start and run timing was right. Changing the rear lag angle ONLY AFFECTS start/impulse timing while rotating the mag in the govenor affects BOTH start and run timing.

John T

 

[rick deere]

Its back as far as it will go do I need to bring it forward some??

 

[RandyB(MI)]

these guys got you right. also you don't need to "throw it" around hard. If it is right and you have good gas and spark it should pull itself right out of your hands when it fires off. once or twice around at most and when you pull it past compression you don't have to pull the skin off your hands , just ease it over compression and it will fire and pull away from your hands.They are fun when they are right.

 

[John T]

If you turn the mag in the governor Forward CW retards and backwards CCW advances but that changes BOTH the start and run timing remember.

The FIRST thing I do is set the rear lag angle adjustment to match whichever drive cup the mag has, i.e. if its a 25 degree advance cup I set the lag angle (definition of lag angle is how many degrees start time lags run timing) for 25 degrees. For a 25 degree drive cup that's 2 1/2 marks to the left, for a 35 degree drive cup that's 4 1/2 to the left UNLESS ITS A 6274 (still 25 degree) DRIVE CUP in which case the lag angle sets 4 1/2 to the left.

Then I install the mag and remove plugs and by turning the mag fine tune it so it snaps at TDC (Left hand Impulse) at 3 o clock.

Then I use a timing light to see where run time advance is and if its from 20 to 30 BTDC I just let it alone.

My good friend the late Duane Larson has this explained in his Two Cylinder Service CD set although we did it a bit differently.

Sorry, but I cant put in a paragraph here what I used to spend over 30 minutes explaining when I gave Seminar Workshops on Wico Mags at Two Cylinder and Gathering of the Green.

Adjust Lag angle to match the drive cup then install and fine tune start timing to TDC, then if necessary re adjust so run timing is where you want it

John T

 

[rick deere]

Thanks Im gonna look at it a little more today.