Start relay puzzle
 

Have good circuits from battery to car and ground. Close the ground disconnect switch and lights, horn etc work. Push start button nothing happens. Checked start button normal open. pushed have circuit. Jump from relay battery terminal to starter post on starter and engine spins. Checked ground from relay to starter/chassis and is good. If I jump from the battery terminal on the relay directly to the S post, there is no click so it seems the relay is not pulling in to contact. Have already replaced the relay once and still the same problem. What am I doing wrong?

It is a 12 volt neg ground system.

Re: Start relay puzzle
 

http://i210.photobucket.com/albums/b...erystarter.jpg

I see a wire missing in yours.

Re: Start relay puzzle
 

You have no ground return on the relay winding. From the I termonal.

Re: Start relay puzzle
 

Great diagram Mike!
I thought this relay was grounded through the mounting base and the I post was not used. This relay has 4 posts (2 large, 2 small) Small ones are marked S and I. Isn't the I post used only during start to supply a boost to the coil? I have electronic ignition by the way and have not yet used the key on the ignition to start the car. Just want to get the start circuit going first. Then I can put gas in the car and try to start it.

Re: Start relay puzzle
 

Do you have a solenoid with an isolated ground? If so you
need the start button hooked to a ground not a hot wire.

Bob

Re: Start relay puzzle
 

This is what I have except I have a stand alone start push button on the floorboard instead of routing through the ignition switch.

Re: Start relay puzzle
 

You have it wired correctly, the i terminal should not be grounded. You have a bad connection, maybe a battery terminal.

Re: Start relay puzzle
 

If the solenoid has a #4 circuit such as a number 572 solenoid
it is wired like Mikes diagram. Is there a number on the solenoid
or box it came in??

Bob

Re: Start relay puzzle
 

If one of the big terminals is marked Batt. on the sol. body, then Bob C is correct.
The diagram Mike shows is a marine set up. Normally the base is ground. If it is purely automotive it should be....Use 1960's mustang starter relays.
Jump (as you did) again and instead of a click look at the wire as you touch it to the S term. It is about a 2 1/2 amp draw and a nice blue spark. If that is present it means your ground is intact. If no spark go from the relay base right to the engine or a good grd, batt if you can get there. retest.
Look at the two #10 studs. Most likely marked S and R(i). R is for resistor by-pass.
To mix it up some manufactures use S/R bodies and R is a ground. Saves money.
For me two #12 jumper wires with alligator clips belong in my "A" tool box.
Oh yes, make sure it out of gear. Kinda important.

Re: Start relay puzzle
 

I know they all look alike,but work in different ways.I have a pile of those old ones,when I want to use one I have to sit down with a battery and some jumper wires and check out how they work.I have a couple that are activated when the switch GROUNDS the little terminal,not power it.I think those may have come from the glow plug setup for the 5.7 GM diesels.About 15 years ago I worked on one of the Miss Budweiser racing boats.I have no idea what class it was in,but it was Pinto powered.The pilot had installed a new solonoid,and it wouldn't crank.He had just picked up what looked like a Ford relay,it was actually a relay to run a Western snowplow pump.They all may look alike,but they may all work different.

Re: Start relay puzzle
 

Wow! I thought it was a simple electro-magnet that pulled a bridge across the two large terminals when powered. I purchased the relay only because it is a 12 volt 4 post relay with a curved base that matched the screw holes on the starter where the old push rod starter attached.

I purchased a NAPA ST73 relay.

Re: Start relay puzzle
 

Actually the old style where the coil is tied to the battery stud (B circuit) is an old ford design going way back. The whole world sent power to the relay- to ground. Ford sent the hot wire to the switch to ground.
Most Ford regulators are B circuit, most everyone else A circuit.

Re: Start relay puzzle
 

It seems even NAPA doesn't know much about their ST73. Seems it does have a insulated base so it the relay isn't marked BATT on the side by one of the big post, follow Mike K diagram.

Re: Start relay puzzle
 

Problem solved!!
Thanks to all who provided input. I disassembled the one I removed and confirmed that the coil was not grounded to the base. I had continuity from the S terminal to the I terminal. I attached a ground wire from the I terminal to the mounting screw from the base to starter housing and after pressing the start button, got engine rotation.

I guess even though the solenoid housing indicated both an S and I terminal, as was stated, it was not wired as an older I terminal for a boost to the coil during starting.

Personally, I would have preferred to keep the original push rod start switch, but the previous owner had changed up things so to start with I decided to just go with the flow.

Now to put gas in and attempt a first start.

Re: Start relay puzzle
 

Pay no attention to how the housing is stamped,or embossed actually.The same housing is used in a dozen different configurations,and it looks like if somebody was out of the correctly stamped housings,they just grabbed a different one.I found years ago that the terminal markings on the Delcotron alternators meant nothing after a rebuild.Different applications had different uses for the terminals,but the housings were the same.