Engine test stand for sbc 305 w/thunderbolt ignition

series60

series60

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I would like to run my 1984 305sbc w/thunderbolt ignition on an engine test stand prior to installation. I have had to completely rewire the engine and want to check all the wiring prior to installation. I have a start switch, tach, electric oil and water temp gauge mounted on a wood panel. I have not found the correct wiring diagram for this vintage boat (see sig). I used a 1985 engine wiring diagram for the engine and I think that part is correct. (fingers crossed). The gray cells just can't sort it all out as to what and were wires need to be connected.

A nice simple schematic showing what wires go where would be greatly appreciated.

TIA,
Bill
 
Alpheus

Alpheus

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Re: Engine test stand for sbc 305 w/thunderbolt ignition

You couldnt ask for a more simple engine to wire.

Here is a link to the service manual you need.
http://www.4shared.com/document/QUg394Vi/Mercruiser_3_1978-1984_Engines.html
Here is a video of a ground run I made.
http://www.youtube.com/watch?v=NUoXFIo2Ab8

I think you're all set. Good luck...

1978-1984v-8WiringDiagram-1.jpg
 
series60

series60

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Messages
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Re: Engine test stand for sbc 305 w/thunderbolt ignition

Great big Thank You -Alpheus. The video did the trick and I replaced my 1985 manual with the 1978-1984 manual. Gee, one with as much time on this earth as I would have thought I could of figured that one out! Been dink'n with sbc since my high school days and my 1955 Chevy 283! Gray cells must be loosing it.

Now if you could tell me where the tach signal wire connects I can connect my gauge panel. I think it goes on one of the coil leads. I hate to assume anything but are all non-electronic equipped Mercruisers able to start this way?

Thanks again.
 
Alpheus

Alpheus

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Re: Engine test stand for sbc 305 w/thunderbolt ignition

You can connect your tach to pin #2 on the plug the gray wire from the coil. All the plugs are the same...

I am ground running these engines so much that I built a remote starter box.

IMAG0092.jpg

IMAG0097.jpg

IMAG0095.jpg

IMAG0094.jpg


Here a a video of me using it a little.
http://www.youtube.com/watch?v=QAlCVA5cCQM

The only thing I need to change between engies is the tach setting. It works great and really comes in handy when trouble shooting electrical problems...
 
Don S

Don S

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62,321
Re: Engine test stand for sbc 305 w/thunderbolt ignition

If you don't want to go through the main harness plug, you can get power to the ignition system by using a jumper wire from the positive battery terminal to the + terminal on the coil. To hook a tach up, just hook your tach to the - terminal of the coil.
To crank it over, just jump the 2 small wires on the slave solenoid.
 
series60

series60

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Joined
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Messages
420
Re: Engine test stand for sbc 305 w/thunderbolt ignition

Thanks everyone. Going out, as they say in Nascar, to "crank it up"!
 
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