Cranking The B61, Info?

[jaysm35a2]

1st ill start with, this might be a dumb question but it will make me feal better to ask it. When you crank your B61 after it sitting for a week or two does yours fire right up? Mine seems to sometimes and others it takes a few tries to get it going. I hit the start button and it goes thunk , or cranks just about then dies. Then I do it a 2nd time and it fires up. But almost all the time it cranks right up. Anyone wanna comment on the old dog?

[vanscottbuilders]

Jay,

Does the truck start well when it's hot?

Or does it crank slow then too?

Just guessing, but based on the info given I think you may have one weak battery,

or a poor cable connection.

Paul Van Scott

[jaysm35a2]

I it should have 4 6V batts right , or will 2 new 12V's work ?

[randyp]

I it should have 4 6V batts right , or will 2 new 12V's work ?

mine has 2 12 volt positive ground and starts real good,,,,randy

[vision386]

mine has 2 12 volt positive ground and starts real good,,,,randy

That was my thinking too, sounded like maybe lose/corroded cable, maybe bad starter button/not making good contact to engage the starter......mark

[HK Trucking]

May have burned contacts in the series parallel switch. Perhaps it makes a poor connection on the initial attempt, then when you try it a 2nd time it connects.

Check with Rob, he likes rebuilding those switches.

.

[Rob]

May have burned contacts in the series parallel switch. Perhaps it makes a poor connection on the initial attempt, then when you try it a 2nd time it connects.

Check with Rob, he likes rebuilding those switches.

.

I must!! Parts can't be had no more unless real lucky, (I'm not). Best ensure your battery terminal connections are both clean, and tight because a high resistance connection such as your symptoms appear rapidly vaporize the contacting metal which is usually copper. The copper ring, and mating contacts are long obsolete but can be remade if one wants with a little money, and a lot of time.

The only reason I took to rebuilding them is my lack of 12V, 42MT starters.

From what I take of your given scenario is this:

When you mash on the starter button and only hear a click, or nothing, but there is still 12VDC power available through the truck's electrical system, (sometimes not) there is rapid heating of a high resistance connection someplace in the high current starting circuit. This temporarily melts a little bit of the connection, or incinerates the corrosion. It is only a matter of time before this burns so much material away the mechanical connection is no longer electrically connected. Basically you can be stuck on the side of the road at this point.

When you take things apart you either find a battery post melted off of a battery, a connection melted at the s/p switch, or the internal section of the switch laying in a pool of solidified copper. I have fond memories of just these scenarios. I learned to fix them out of necessary rather than just being cheap because I didn't know any better.

Knowing the truck is completely 12VDC in the electrical system other than the starter motor, I just move to the aforementioned starter motor. The 42MT starter has the solenoid built onto it like a pickup truck. You just wire from the dash switch to the starter solenoid "S" terminal. When you mash your starter button now, it kicks in the solenoid on the starter. You can then eliminate the s/p switch between the seats but do run the battery cables in parallel fashion to the starter solenoid. Also ground your battery negatives, (or positive depending on the truck's polarity) to one of the bolts that retain the starter to the block or flywheel housing. A 12VDC starter draws one hell of a lot of inrush current amps when it starts to crank the engine and you want your electrical connections as close as possible to the draw so the chassis doesn't become part of the circuit.

Now dammit Herb, I had to open the cold storage locker for that tidbit of information. Don't get me started again as things was starting to thaw.

Rob

[jaysm35a2]

I went out , cleaned up the terminals, put the cables back on , tightend them real good. Nice ,clean, tight , ready for me.

[Rob]

I went out , cleaned up the terminals, put the cables back on , tightend them real good. Nice ,clean, tight , ready for me.

You're well on your way to solving your own problem. Always good to have the variable knocked down or isolated.

Rob

[jaysm35a2]

I went out today and started the truck about 4 times, first time it sounded like a dead batt. not a thunk but a small click , then I hit the button again and it fired right up real quick and nice. Ran for a few as I moved it around and let it run and then shut it down. Cranked it after that and it fired up , then tried again a few min later and it fired right up again. So thats the new update on the green machine.

[Rob]

I went out today and started the truck about 4 times, first time it sounded like a dead batt. not a thunk but a small click , then I hit the button again and it fired right up real quick and nice. Ran for a few as I moved it around and let it run and then shut it down. Cranked it after that and it fired up , then tried again a few min later and it fired right up again. So thats the new update on the green machine.

Take the series/parallel switch apart and clean the internal contacts before you destroy them if you've already cleaned the battery cable connections.

This is a common problem and parts are hard to come by anymore.

Rob

[jaysm35a2]

Battery terminal goo wouldnt make them do that right? I have some red terminal protectant or whatever it is ,still on one or two terminals just a small bit though.

[jaysm35a2]

Rob. Also hes the picture -

[Rob]

That plate that is riveted or bolted to the floor covers where the series/parallel switch used to mount. Most likely yours has been converted to 12VDC start and no longer uses the switch. Look at you starter, is is long and round with a bolt on flange at one end to mount to the flywheel housing? Does it have a solenoid mounted directly to the starter motor with the heavy battery cables attached to two large center terminals and smaller wires connected to the smaller terminals? If it has a solenoid chances are it is 12VDC start. If you have cleaned all the battery terminals take each bolt loose that mounts the starter to the flywheel housing and clean the area with a wire brush or sandpaper. Also look for a heavy ground wire on the starter motor itself and make certain it is also clean.

A 42MT starter such as the one described also has a large copper ring internal the carries all the starter current. It, over time will burn just as the series/parallel switch discs will. These too can be cleaned, or flipped to produce a new side for contact. These solenoids however are readily available and for usually just under $50.00 , most consider them a throw away item.

Rob