• If you like antique engines, vintage tractors or old iron, please register and join us. When registering, please provide your CITY and STATE as your location!

Webster magneto no spark

P

PhilBrown

Guest
Hello everyone

For those of you who don't know, I dug an old massey harris type 1 out of a pile of rubble here in France about a month ago. Now I have freed up the engine, having to strip it right down and build it up again, and all went back together well, but the magneto suffered the worst corrosion with the alloy parts very corroded, however I don't think this affects its performance, but I don't get a spark. The cam throws fine, and strikes the points, but there doesn't seem to be enough current coming out of the coils.

Could this be weak magnets ? or just poor insulation ?

I measured the coil resistance to be around 7 ohms, and the resistance to ground about 1 meg

Can anyone give me any pointers on this?

Thanks

Phil
 

KidDynamo

Registered
Last Subscription Date
11/10/2018
Re: webster magneto no spark

You might gain insight by removing the springs from the magneto and after making sure that it will turn all the way around, spin it with a drill motor and read the voltage output with an analog voltmeter.

I can't remember what your readings should approximate, but hopefully you will see something in excess of 7 volts. The bushings in the end plates should ideally have little enough wear that the armature doesn't contact the pole pieces.

Readings with a digital meter are okay but may require some interpretation. Regardless of what meter you use you gotta see some output, right??

It is kind of hard to guage magnet strength by touching the magnet. Removal of the magnets or removal of the armature without a keeper on the magnets can cause a loss of strength. Some say this would require magnet recharging however most Websters I have refurbished worked great without a magnet recharge. (I have two chargers.)

My favorite tests is to remove the entire ignitor/magneto assembly from the engine and use a starting lever cock and trip the magneto in a darkened room while staring at the points. A good spark is obvious and quite impressive! Starting levers use the two extended spring roller posts- one as a fulcrum and the other for "prying" on. When you cock the magneto, the lever holds it in the wound up position at just the correct amount of "twist" (40 degrees). Then when you're ready, you give it a little pry and it releases the armature and it cycles itself and pops the igintor points.

The lever can be obtained for not much money from several of Harry's sponsors. I checked Hit and Miss Enterprise's reproduction levers with a perfect original lever and they are an exact match! A screwdriver can be a poor substitute if you can secure the ignitor in such a way as to view the points.

You also need to make sure that the points are closing all the way, your magneto is wound up to 40 degrees prior to tripping when on the engine and that they are knocked open, momentarily, when the mag is tripped. This is another reason the starting lever is so-o-o-o handy!!
 

Rudy

Sponsor
Last Subscription Date
03/07/2018
Re: webster magneto no spark

Anytime a magnet or the inductor is removed on a Webster the magnet must be recharged. Seeing if the mag had spark outside of the engine means nothing. As soon as it has to spark under compression it will fail.you are working with low tension here. Its the difference of starting the engine on the mag or not.Also make sure that there is no lateral movement on the ignitor bracket moveable contact. If you have lateral movement the spark will be gone by the time you have rotary movement.Webster mags work real well if they are repaired right, and not patched like a lot of the crap that you can buy on E-Bay. Usually the warranty that the seller gives, which is none tells the complete story.
 
P

PhilBrown

Guest
Re: webster magneto no spark

Thanks guys, thats great, I'll try spinning the armeture and let you know the results, If that works then I guess I'll have to look at the adjustments carefully, i.e. when the points open in regard to the armature throwing.

Another thing, how many springs should there be ? because I have one spring on each side, but it looks like there may have been another spring on one side because the posts are longer.

Thanks again

Phil
 

Paul Spence

Subscriber
Last Subscription Date
01/02/2020
Re: webster magneto no spark

"Another thing, how many springs should there be ? because I have one spring on each side, but it looks like there may have been another spring on one side because the posts are longer".

Phil: That's where the starting lever goes :) .
 

Gary Pflum

Registered
Last Subscription Date
01/05/2014
Re: webster magneto no spark

Hello,
I have rebuilt a lot of Websters for engines in the last 20 years. The common areas to check are the magnets (charged properly) The armature bushings (not worn to the point that the armature rubs on the pole pieces), And of course the coil condition. The MOST common problem I have run across is when the mag has been disassembled cleaned and reassembled. When the mag is reassembled, the armature is installed BACKWARDS. The armatures have 4 wings on them. 2 small and 2 large. Many people do not see the difference. The armature must be installed so the large wings aline with the pole ends when the mag is in the cocked position. If the armature is installed backwards end for end it will not work or will throw a very weak spark. The only way to check this is to remove the end plate (perferable the spring end) and look at the armature when it is cocked. You will see that the 2 large wings should aline up with the poles. If not remove the armature and reinstall it end for end.
 
P

PhilBrown

Guest
Re: webster magneto no spark

Hi there

I tried the drill motor connected to the armature, and got a reading of about 10 volts on the AC scale, (this is a digital meter) but it was a bit intermittent, and I had to spin it pretty fast to get that reading. So can I assume that the coils are ok and the magnets have enough charge ?

There is quite a bit of end to end movement on the armature shaft, and I think the bushings are quite worn (when turning is by hand I can feel some mechanical contact. armature touching the sides I suppose)

So I dont know what to do next, seems to me that all the mag parts need to be in good shape for it all to work well.

Does anyone know who I should contact for a rebuild?


Phil :(
 

Chip Watford

Registered
Re: webster magneto no spark

Phil,Some end play is normal.But ,as Rudy stated,side to side play in the shaft is a problem. Chip
 
Top