Starter/generator; MD6A.

[shanachie70]

Hello group.
When my starter/generator burned out, I was fortunate to find a used unit for free. It is difficult to get this unit rewound and very expensive, so for once luck was in my corner.

Before I installed the new to me starter/generator, I decided to re-wire the fuse panel as well as the electrical distribution, for through the years it had become a night mare of modifiations with no changes noted in the schematic.

I installed Guest battery switch ( standard one/two/both/off type ) Replaced all fuses with circuit breakers, new ignition switch, and new panel switches as well. Last, but not least, I wired the boat for shore power

The engine had been equipped with a Bosch alternator on the starboard side, which was ready for overhaul. I junked it and replaced with a Delco-Remy unit (62 amp) I discontinued the generator side of the starter/generator and use it as a stater only.

I will grant that the Delco-Remy has a bit of over kill amperage-wise, the reason it was chosen was because it fit the mounting bracket. The only modification here was to bore the mounting lug on the alternator and the mounting bracket to the same size (7/16 inch) The Volvo has no trouble turning it to charge one flat battery, but lugs when both batteries are put on line when the reading is 11 volts or less.

This simplified my wiring as the new alternator has an internal voltage regulator, and the new Guest battery switch has field disconnect, so that if the key is inadvertantly turned off while running, nothing bad happens.

Hope some of you find something of interest in this.

Don.

P.S. A tip for anyone requiring a replacement for the Bosch starter/generator on the MD6A or similar engine so equipped, Delco-Remy makes a unit for the Farmall Cub yard tractor that can easily be modified to fit. The price, when I last checked was $387.00 (Cdn) plus shipping. I have the Delco part # somewhere at home ( a long way from here.)

 

[groundhogyh]

Thanks very much for the info.

Does anyone have part numbers that I can use as a starting point for me to find a solution to this? Dynastart part numbers, aftermarket units part numbers, etc. It will help me greatly in my search.

Since I have never seen the parts that are supposed to be on this engine, I don't even know what the thing looks like that I am searching for.

As previously described my MD6A only has an automotive alternator mounted on the starboard side of the engine. I have to hand crank this thing to start it. No fun.

The original Dynastart, was that on the starboard or port side of the engine?

And, this is going to sound stupid (especially coming from an EE) but what is the difference between an alternator and a generator? Is one DC and the other AC with diodes?

I am going to try to find that tractor part on the net. The previous owner has already put the 1/2/both/off switch on the boat.

Thanks again,
groundhog

 

[groundhogyh]

Hi Don,

you wrote...
"This simplified my wiring as the new alternator has an internal voltage regulator, and the new Guest battery switch has field disconnect, so that if the key is inadvertantly turned off while running, nothing bad happens."

Bad happens.... hmmm. I don't like bad things happening. Now I am scared cause I don't know what you are talking about.

What is a field disconnect and how do I tell in I have on on my boat and if not can I add one? Electrically, what is happening when you turn your key off?

Thanks,
groundhog

ps. Don if you are away from your house, but in your boat, maybe you can look on the actual part for a part number(s)? I searched the Delco-Remy and Farmall Cub for the alternator and I just get so many years worth of parts, I can't seem to focus on the unit you are using.

 

[rchrdcoe]

groundhog-
You've got it right as to alternator versus generator. All cars now
use alternators. The dynastart is mounted on the port side, with two
belts to the flywheel. I'll look in my engine manual for a part
number when I go up to the boat. I'm currently waiting for the
mechanic to complete the overhaul of the head. Soon I hope.
Richard, V1812

 

[vegasailor2001]

Hi!

If you take a look on the instruction manual for the Volvo penta MD6A, there
is a picture on the engine and the position of the dynastart (position 12).
If you don\'t have it, I am sure it can be found on the internet. A swedish
version (with pictures), can be found on www.forsmarin.se, but I am sure
there is english ones availible.

Yours,

Björn
Vega 2757

 

[groundhogyh]

Well, the previous owner of Good Things found the old original starter/generator and we installed it on Saturday.

Problem is, it runs REALLY HOT. You can only hold your fingers on it for like .1-.2 seconds. That sounds to me to be about 75C or 170F degrees. I can't imagine the unit will run for long that hot.

Is that normal for it to run that hot?

It is set up like Don's boat. There is an automotive alternator on the starboard side. The generator on the starter/generator side is (I think) only set up as a starter. To do this only the large D+ wire (switched battery hot), the ground wire, and the DF wire are connected.

I am wondering if the DF wire can be disconnected. Could that be causing it to run hot...? Maybe there is some fighting going on inside. Guess I'll find out.

Anyway, thanks for all of your observations.
groundhog

 

[rchrdcoe]

To Groundhog-
If you are still needing that part no. for the dynastart here it
is;Bosch 0 010 350 004 . The specs further state that the gen output
max is 135w and 90w continous. They list the starter output as
0.74kw (1hp). These fig. are from the engine workshop manual.
Hope this helps.
Richard V1812

 

[coonhopper2000]

Feedback on starter generator for MD series. German mechanic with detailed knowledge of Dynastarter says disconnect charging feature of same making it just a cranking device utilizing cheap Ford relay and install #2 wire for positive. It makes sense, if you have the optional alternator. He says the Dynastarter was meant to charge a particular series of battery that is not used anymore. With the heavier guage wire and only used as a cranking device with the Ford relay it is much stronger as a starter. Currently having to start with the compression lever up for starter to function and not sure if it is charging. By changing system can kill two birds with one stone.... Pat V2137 Puffin
If you are still needing that part no. for the dynastart here it
is;Bosch 0 010 350 004 . The specs further state that the gen output
max is 135w and 90w continous. They list the starter output as
0.74kw (1hp). These fig. are from the engine workshop manual.
Hope this helps.
Richard V1812

 

[coonhopper2000]

Regarding Don's note to Vega group. Would be very interested in wiring diagram for engine panel lights as I have my panel torn apart right now and trying to figure out the whats what on the gen,alt,oil, warning lites.. Thanks, Pat

highseasrover@... wrote:

 

[coonhopper2000]

Terrific, THANKS DON.... pat

highseasrover@... wrote:

 

[groundhogyh]

THanks for all of the terrific feedback on this issue.
My situation now is that the previous owner found the original starter/generator. We installed it. It runs hot, like 75C or 170F.

Don, I have contacted jebco and am awaiting info on the starter you used. This sounds interesting to me because I think this unit will only take me so far since it is running so hot. Don, are you using the original unit or the Delco-Remy unit as the starter?

Richard, thanks for the part number. I did a search and there are some used units on the market.

Pat, our attempt when installing the starter/generator was to only use it as the starter. There are normally 4 wires attached to the unit. D+ is the heavy current carrying wire. D- is ground. DF? is the field wire (I have this connected because I was told this is needed to energise the field.). The only wire I don't have connected is 30h. (Notations from handbook schematic)

Yours,
groundhog