MH 333 again

[Harryaroo]

I'm working on my MH 333 again. Broke the throttle shaft during the winter-- replaced it but now won't start. I have electricity to the coil. If you touch various parts of the distributor with the ignition on, there is spark but no spark at the points when cranking. No spark at the plugs. It was doing this last year-- I replaced the spark plug wires and it ran for about six months. I can't imagine it's the wires again....

 

[used red MN]

If you touch various parts of the distributor with the ignition on, there is spark but no spark at the points when cranking.

What are you touching the distributor with to get a spark? It seems odd but maybe the distributor has lost its ground connection(continuity) to the engine. Is whatever holds the distributor in place tight? Do you have an automotive test light?

 

[Harryaroo]

What are you touching the distributor with to get a spark? It seems odd but maybe the distributor has lost its ground connection(continuity) to the engine. Is whatever holds the distributor in place tight? Do you have an automotive test light?

I have a test light-- alligator clip and a probe. I'm touching the inner parts of the distributor with a screwdriver. Is it normal to get sparkes off of the shaft and various places but nothing at the points when cranked. Distrib seems tight-- I'll check ground.

 

[used red MN]

I have a test light-- alligator clip and a probe. I'm touching the inner parts of the distributor with a screwdriver. Is it normal to get sparkes off of the shaft and various places but nothing at the points when cranked. Distrib seems tight-- I'll check ground.

Clip the alligator clip of the test light to a good ground on the engine. Touch the places on the distributor where you claimed a spark was seen does it light the test light? It should not because it should be grounded or in contact with the engine block. Is the plate the points mount to loose? In the end when all is right with the ignition on probing the terminal on the coil that has the wire from the distributor on it you should have power when the points are open and no power when the points are closed. And when cranking the test light should flash on and off. If when the points are closed and the light is still on that means that the points are not making proper contact.

 

[Jim.ME]

You can get a spark of probing around in a distributor, and not see a spark at the points when cranking. If it makes a spark when you are proving things, it would indicate the distributor is grounded to me.

Have you cleaned the contacts by rubbing a piece of uncoated card stock, or piece of brown paper bag, even a folded up dollar bill between the closed points? They can develop a coating that insulates them when setting.

 

[Jim.ME]

Also check to see that the moveable arm of the points is not sticking. I have had one with a sticking arm open after setting.