Re: [MV] M151A2 Starting Problem - Solved (I hope)

From: David Cole (DavidCole@tk7.net)
Date: Tue Aug 05 2003 - 07:22:25 PDT


You don't have a voltage problem in the system if you can maintain 23.4
when cranking!

There is something else that is wrong. There should be a resistor in the
distributor I believe (there is one in my M51 5 ton dump) that limits the
current through the coil. In order for the coil and points to work
properly current must flow through the coil. Check for voltage across the
coil when the points are shut, you should have something like 3-6 volts.
The resistor drops the other voltage when current is flowing. Then check
for voltage when the points are open. You should have zero volts across
the coil. Of course the ignition has to be on when you do this.

If you don't have 3-6 volts then something is out of wack. Perhaps you
have a bad connection, an open resistor, or really bad points. (It doesn't
take much corrosion and dirt on points to make them worthless) When the
points are closed and the ignition is on, you should have no more than a
fraction of a volt across the points when the current is flowing. (like .1-
.3 volts) Any more and you need to replace the points.

If you have a decent voltmeter, you can find this problem pretty quickly.

Dave

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

On Tue, 5 Aug 2003 13:45:28 +0200, Antonio Regazzoni (Home)
<antonio.regazzoni@bluewin.ch> wrote:

> Hi list,
>
> I think I'm having the same problem as Rich Sherman. I have a M151A2 with
> two good batteries. They are not charged 100% but I can measure 12.6 V on
> both of them. This makes 25.2 V total. When I crank the engine I can
> measure 23.4 V. The engine doesn't start !
>
> I cannot believe that the ignition system is so sensitive that with 23.4
> V doesn't give enough sparks to start the engine. I'm thinking that the
> problem could be in a big voltage drop between the batteries and the
> ignition coil, or a bad coil or capacitor.
>
> I will measure the input voltage at the coil and check all the electrical
> connections from the battery to the ignition system.
>
> Any comments ?
>
> Thanks,
>
> Antonio Regazzoni,
> 1944 MB
> 1974 M151A2
> 1975 Pinzgauer
>
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-- 
Dave


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