Ransomed MG2 magneto

[martin-l]

Hi all I am a new member of the club and am seeking some help advice on my newly purchased ransomed mg2,I have not been able to get it started so far after doing the normal i.e. Cleaning the carb out testing for a spark and I have had the head off to set the timing up ,I have tried to set the magneto timing but when I slacken the drive sprocket to allow the sprocket to move freely on the taper shaft I do not get a definite click from the magneto as I do when the sprocket is tightened up ,making it hard to set the mag up is this normal? Also despite the fact that I am getting a good spark I am going to get the mag tested/ repaired/ rebuilt as necessary but before doing so I would like make sure the present mag is the right one it is a wico series A type 1057B my engine in the ransomes is TB7110 so if anyone could confirm this is the right one for the job (as I don’t want to get it refurbed if it is not right) and also any recommendations for someone to carry out a refurb on the mag. Thank you in advance for any help.

[wristpin]

Hopefully someone who knows what they are talking about will give you chapter and verse but when checking for a spark only do it via a spark plug firmly clamped to the mag base. Holding the bare lead away from the base can over stress the internal insulation and cause internal tracking . If you are sending the mag out for rebuilding, make sure you get a quote, those that know what they are doing can be more expensive that you may imagine.

[martin-l]

Yeh thanks for that I am bracing myself RE the Ransomes magneto!

[oddhatuk]

Neil Jarratt is the best person to ask, he is ransomes256 on here.

[expeatfarmer]

Hi Martin, you have the correct magneto, to set the timing loosen the lower of the two timing chain sprockets ( the smallest one ) set the crank to exactly top dead center. With the timing chain lower sprocket slack, rotate the larger sprocket on the magneto until you hear it click, reverse rotate the mag sprocket about 60 degrees and nip up the lower sprocket clamping bolt. Make a mark on the flywheel and the crankcase at top dead centre. Turn the crank over until you hear the magneto click and observe the position of your two timing marks, if they match job done, if not note how much they are apart either advanced or retarded and then slacken lower sprocket clam and loosen sprocket on the taper move the magneto sprocket in whichever direction needed to close the gap on your marker points, clamp up the sprocket and repeat turnover repeat until the click and your two TDC timing marks are all lined up. This will create spark ignition for starting at top dead centre. Make sure that the magneto internals move freely so that when the engine starts it can advance to 20 degrees and return to Zero when the engine stops.. Have Fun!

[martin-l]

Hi thanks for the info, I have tried following your instructions but the problem is when I loosen the lower sprocket on the crank taper shaft and turn the magneto sprocket independently I get no definite click making it difficult to time the magneto with TDC of the crank is this normal ? As when the lower sprocket is tightened on to the taper shaft and is turned there is a very defined click compared to when I turn the magneto independently ! Is this a sign of a faulty mag spring?? Or just a sign of me losing my hearing more than I thought ??

I appreciate any further help/ advice

[wristpin]

Not knowing anything about the setup on the MG but having a couple of Wico type As on other engines I would just say that the click is generated entirely internally by the tripping of the impulse unit and should not be affected by any external adjustment; assuming, of course, that the mag is being turned past the tripping point – are you sure that the adjustable sprocket isn’t slipping?

[martin-l]

I am pretty sure it’s not slipping as I have been turning it by the sprocket and centre bolt but I will double check when I get it on the bench . Thank you

[expeatfarmer]

Hi Martin
If the magneto clicks when all is tightened up are you turning the crank over with the starting handle or by pushing on the fywheel. If so when you rotate the sprocket on the magneto with the lower sprocket loose try rotating the mag sprocket in the opposite direction to that which you have been. The impulse dog will only engage if the mag is rotated in one direction if it clicks with the chain and sprockets tight then the only reason for it not clicking with the chain free is if it is rotated the wrong way.

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