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Blew another seloniod on 1976 Ford 302

no, it doesn't rule out the solenoid...that is the same test in the old Ford service manual and it doesn't segregate the components very well.

the attachment should have a pictorial of what I tried to suggest a while back... I'm still not certain I completely understand the results of the tests you did make as something just doesn't add up to me....

I haven't even looked for a PMGR starter for the fords...I know they make them for the street so a marine version shouldn't be too hard though there may not be a lot of options out there....either way, doing the wiring changes should be straight forward...
 

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  • voltage drop tests for Ford.pdf
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here's one option for the PMGR starter:

https://www.marineengine.com/newparts/part_details.php?pnum=ARC70200

for completeness, you can also check the voltage drop between the Battery - terminal and the block AND between the block and the starter's case.

there is definitely something not supporting the current draw - either a bad connection or an inadequate source....may be worth scanning the connections with an IR gun is the voltage drop test fails to ID one or more root causes...
 
I didn't have time to do my homework - the dog ate it.
I look at these starters and they are not symetrical between the two bolt holes and the starter gear, as mine is, so I wonder if the distance between the bolts is the same or not, and if that change in geometry will actually mesh the gears. I did look it up and it said "equivalent", but I didn't see any figure on the distance between the bolt holes or anything that would reassure me of it's fit.
Do you have experience with this? I would order it in a second, if I was at least somewhat sure it would work.
I did get the $25 harbor frieght IR gun.
 
I have no experience with PMGR starters on a marinized Ford small block...that said, I have used many ARCO products over the years and never had any complaint with them...I'd be willing to bet the starter will work but not sure your engine is ready for it at this time.

Maybe giving them a call this morning would be the fastest was to get some level of comfort.
 
I sent my questions to both marineengine.com and Arcomarine.com, so hope to have an informed reply. I will pull the starter this weekend and get it checked.
 
excellent...fingers crossed.

Just to be clear, I'm thinking there is still ca bad connection/wire somewhere in the starting circuit....and, until that is fixed, I would doubt the PMGR starter will make a huge difference....now, once the wiring is dialed in, it will make the battery much happier...
 
I will do the voltage drop tests you suggested first, before I take out the starter and get it tested before I order a new one.
Everything is new, the connections are in new condition. Can it be made any better?? I'll do the tests and get you the data.
 
I have seen new material that was flawed as have parts, too...I've seen battery cable connectors covered with an (assumed) spray on clear coating that wouldn't allow the solenoid to engage...

I think the modified test will give more insight.
 
I found the correct Arco selonoid, so will probably order it with the starter, if and when we think this is a good idea, after the drop tests.
 
Here is the results from the drop tests you requested:
#1 Batt + & selonoid Batt post = 0.0 to 0.1 = 0.1 (good)
#2 Selonoid batt post & Sel. starter motor post = 12.8 to .7 -12.1 (way over)
#3 sel. starter motor post & Starter post = 0.0 to 0.08 = .08 (good)
#4 Starter post & Batt- = 0.0 to 11.0 = 11.0 (way over)
#5 Batt- & Block = 0.0 to 0.0 - 0.0 (good)
#6 Block & starter case = 0.0 to 0.0 = 0.0 (good)
I haven't taken out the starter yet.
My guesses:
On #3, either it is a wrong selonoid, or something is hooked up to the selonoid wrong.
On #4, bad starter or wrong starter.
 
#2 says the solenoid is not passing adequate current - I would assume burnt contacts inside of it.

#4 includes the solenoid in the current path, so that isn't a surprise to me anyhow...

the balance of the data points indicate good healthy connections..assuming your battery is adequate

I would suggest the following next steps: 1) make sure the battery is fully charged, & 2) replace the solenoid - leaving the small wires and the starter wires OFF for the time being. I would then do an incremental test as follows.
connect the yellow wire from the key switch to the S terminal of the solenoid. hook a test lamp between ground and the BIG solenoid lug for the starter. Active the key switch (to start) and the solenoid should close and the test lamp should glow and it should go off when the key is released. then repeat this test but with the test lamp lead moved from the BIG solenoid lug for the start to the small I lug on the solenoid. again, the test lamp should glow. This will validate the solenoid function (but for only small currents.

You COULD then reconnect the starter wire to the BIG solenoid lug for the starter. and then try the starter if you want...worst case would be if the starter's current draw is excessive and you burn another solenoid. Ideally, you could do a current draw test on the starter but my guess is you don't have a high current DC clamp on amp meter available - maybe one of your associates has one they could loan or make the measurement for you. next best thing (which I'm sure you have been avoiding) would be to remove the starter and have it bench tested...

rereading the thread, as of now, the issue has been narrowed down to the solenoid, the interconnecting wiring, and or the starter....the tests above will let you know is the new solenoid behaves 'well' which leaves wiring or starter. I don't see any major issue in the wiring but I will confess and say I am not fluent with the 'old' ford marine alternators or their wiring...pretty certain the excitation comes from the IGN circuit supplying 12VDC with the key in RUN. enough for now...
 
the test results you provided from today indicate a huge voltage drop across the installed solenoid which says the contacts are bad....how it got that way is hard to say but it could be the starter is drawing too much current.

Hopefully ARCO will get back to you about their options...they aren't the only potential source and I have seen others that also have a solenoid on the starter.

the history of what you call the "double relay"....on the auto applications, the wiring run from the battery to the key switch and then to the starter parts is fairly short and well controlled....when they went to boats, especially larger boats that had the control station in a flying bridge configuration, there were may instances where the engines wouldn't start...so the smart guys got involved and they figured out all of that 'extra' wiring was inducing a voltage drop in the starter wiring to the solenoid (typically drawing 20+ amps on the GM style...so they added a slave solenoid which was low current and closed reliably with the 'extra wiring'. When the slave solenoid closes, it enables the higher current main solenoid to do its job. The ARCO literature I saw stated they give you a harness and directions to make the wiring changes...I've never installed a ford version of the PMGR starters in the marine world so can't say what they provide it as advertised...that said, I haven't heard or read of any gripes
 
So that new selonoid has about a minute of run-time - just for the drop tests, which only take a couple of seconds each. I hardly think the contacts went bad that immediately, unless the current is so strong that they were welded. I think there is something off with the wiring to the selonoid. My suspicion is the ignition wire that I added to the selonoid (I) terminal, when I bypassed the ballast resistor. That it doesn't actually have to be connected to the selonoid at all and can be linked to the coil and choke wires independant of the solonoid, as the only reason it went though the selonoid at all is to get the full 12 volts when starting, instead of being routed through a cold balast resistor. Then there is the wire going to the yellow plug, which could be disconnected as well. We could diconnect them all and see if the starter is more perky. And do the tests that you suggested, which I would have to rig up a test lamp. Could I use a continuity tester? I am having a bit of a hard time following your tests, the diagrqm you provided last time really helped. Or if it is pointing in that direction, just pull the starter and get the new PMGR ARCO stater and selonoid.
I haven't heard back from Arco yet, but I am more convinced that it will work, as the geometry looks different because the starter motor is so much smaller, and they needed room for the selonoid, so made they it asymetrical, but angled it so as to make the gears mesh.
I have been looking at schematics for PMGR starters and they pass the high current from the battery and the battery side of the selonoid to the starter motor with the heavy gauge wire and use the switch of the selonoid to trigger the starter selonoid with a lower current and smaller wires, so there will not be a great deal of amps going through the current solonoid. They do that so that there isn't this large current going all through the boat to the ignition key, which would have to be a heavy switch. So we have three swiches to turn the starter, one manual and two electronic, to keep the high current contained only to where it is needed.
 
exceeding the current rating on a pair of contacts is guaranteed to shorten their operating life...

Unless there is something amiss in the smaller (control) wires going to the solenoid, keeping it active, the only thing I can imagine is the starter drawing too much current (measuring that was mentioned). Doing the tests I suggested, with a test lamp, will let you know if there is any remaining continuity across the solenoid's contacts - a continuity test doesn't require more than a few milliamps of current...a test lamp will usually draw at least an amp (think 1156 auto bulb)...
 
I'd also guess that you can use a mini ISO relay cube in place of the solenoid as long as you get one with adequately sized contacts (for the solenoid on the PMGR unit)...
 
I did my test of just pulling off all the ignition related wires from the selonoid (I) terminal, and bolted them together; and disconnected the wire going to the yellow plug from the (S) terminal and got the same results, slow crank and I did a drop test across the selonoid large terminals and got the same result, approximately 12.6 drop. I even took off the wire from the Batt selonoid to the tilt selonoids and same results, including the drop test. The only things left were the red 0 gauge battery cable, the red ignition 10 gauge, the red alternator 10 gauge wire and the 0 guage black cable to the starter. I then took off the red 10 gauge alternator wire and got the same results, including the drop test, with the selonoid naked of everything except that which is essential to turn the starter.
I then went to your tests, having made a test lamp soldering a 12 volt lamp and wires with aligator clips and both tests (the large starter motor lug to ground and the (I) terminal to ground) came out good with the lamp lighting when the starter was activated and off when not. Of course this was with the same selonoid that still has less than a minute run-time. I really don't want to put on a $40 selonoid if it is going to burn out in a mili-second.
The mini ISO cubes all look like they plug into a socket - I'll probabluy just get the Arco selonoid.
My guess is that next we pull the starter and get it checked out.
 
that tells me the solenoid contacts are damaged and won't pass enough current for the starter but will pass the 1 amp or so for the test lamp...

I would agree testing the starter would be the next step. the only other things in the path are the large cables and you said they have been replaced and are brand new...

you may NOT need the ARCO solenoid if you go with the PMGR starter...if ARCO doesn't reply there are other sources...
 
I pulled the starter and took it to Autozone and it was a fail. No numbers, but the main connection smoked while testing and the gear barely engaged. Looking at the gear, it didn't look worn and it looked like it did engage the flywheel pretty well. Measuring back where it engaged the flywheel puts the flywheel about a half inch from the block.
So do we blame the starter fail on the pour wiring that we fixed? It also looked like it got a bit wet from the rain, so I will have to fix that. And the selonoid fails for the wiring and/or the starter?
I assume you think I may not need a new selonoid because we will have much less current going through it, and it is operating okay for now.
I am a contractor and am looking for a project right now, so I will have to wait for the starter until I close something.
Like I said, I am fairly confident the 70200 starter will work. I'll just order it when I have the funds available and pass on the selonoid for now. IfI knew it was 5 3/8" between the bolts, that would nail it (standard Ford two hole startrer).
I think I will leave the ignition wires off of the selonoid - it was just a convenient place to connect them.
 
hard to say what started the process but I would guess that the starter and wiring issues took out the multiple solenoids...rain water intrusion into a starter will kill it for multiple reasons...changing the wires improved things but with the starter smoking, that suggests it was drawing much more current than normal which would have crippled the newer solenoid(s)...

I will send you a PM with another thought.

Understand the timelines and work driven constraints....

I would be inclined to replace the solenoid or change it to a mini-ISO form factor relay (for the lower current PMGR starter)...with it being damaged, the contacts won't have much service life and being offshore is not the place for marginal electrical parts...
 
In that Description, I am positive LH refers to the engine rotation...which is the predominant rotation from that vintage as well as today. A LH engine using a bottom mounted starter should use a CW rotation starter...

$30+ for that relay is unbelievable...you can get a brand name 40A version delivered for under $10...and the socket and pigtail for about the same cost as the relay...
 
My new Arco 70200 starter came in today and I installed it after work. I used a new Sierra Marine selonoid that I ordered, but they either sent the wrong one or I mistakenly ordered it, as it only had three posts instead of four, like a tilt selonoid, so I kept it, but decided to use it now, as I am not using the fourth (I) post, anyway.
It seems it is spinning faster and I tried turning it 10 times for about 10 seconds each and waiting a few minutes before trying it again. It did not slow down, and the battery didn't drain down very much (it went down to 12.4 and rapidly came back to 12.9 or so), so I believe we have success! Thank you very much!!
It still has the spark plugs out, so I was wondering if I should prime the oil pump through the distributer first, before putting the coil wire and plugs back on and actually trying to start it. Probably would be a good idea. Any other tests you would like to see?
302 schematic as-is.jpg
 
Glad the PMGR part works! I don't think you have anymore troubleshooting to do on the starting system.

It wouldn't hurt to prime the oil feed system....but, if the plugs are out, you can probably just use the starter to do the priming...maybe 20 seconds of cranking and two minutes to cool in between....maybe 4 or 5 cycles or until you can see the gauge move off of the peg.

And I trust you will get a marine rated distributor as funds become available.
 
The directions on the new starter said that the new smaller starter wire on the selonoid (S) terminal should be the only wire on that terminal, and we still have that wire that goes through the yellow plug towards the console. I have disconnected it before and seeemed to have no effect upon anything. I did check the tilt and it worked. The only thing I didn't check was the shift (may need to be running). It seems the tilt selonoids get their power from the Battery terminal of the selonoid, and I think the shift does as well. All the wires from the remote control goes towards the back in that area, I believe through the yellow plug. Should ground it to the engine, just cut it off or insulate it?
What else would need to be powered just when you turn the starter????
 
My mistake, the small wire to the starter is the only wire on the big starter terminal, but we still have the other wire on the (S) terminal that goes towards the yellow plug. But it still is a mystery of what else would need to be powered up when you turn the starter key.
Yes I will get a new distributer soon, before I go for sea trials; but would like to try to get it started with the existing one for now.
I think I will try the distributer oil pump prime. It seems the engine has been spun a lot already. I haven't watched the oil pressure gauge, so I may try that and report back.
 
You have more insight into what the engine has been thru than I do...I'd agree, make sure it starts and runs with what you have before making another change.

On the yellow plug, I'd be inclined to tape its wires up for right now.

No real mystery as to what needs to be powered...the solenoids are the main items, the ignition 'assist' may or may not be needed, depending upon the ignition system used...with a three terminal slave solenoids, that is OBE...

On the yellow plug, it may be tied to the shift assist (ESA??) scheme that OMC has used...I honestly haven't messed with enough to remember when they get used and on what applications...may be worth looking into that one more...
 
I did both methods of priming the oil pump, by your suggestion and taking off the distributer and spinning the pump for over a minute at high speed with a drill - it only took a 1/4" driver to connect to the pump. The oil gauge went to 45 when the ignition was turned on and stayed the same when starting - that was constant before during and after the priming. I them checked the spark, and I didn't have any and found it was the emergency shut-off. I hate those things, but I have very good dpark with the iridium plugs and the 65,000 volt coil. Then I checked the timing, verifying that I was on the compression stroke with the thumb test, and got it very close to the 10 degree advance with the timig light. I put the spark plugs back in and connected up the spark plug wires. Then I came in to watch the Trump rally. I am going to try starting it tomorrow.
 
sounds like the oil pressure gauge is not connected to an oil pressure sending unit or the wiring between those two is bad...

I guess you felt the resistance in the drill when the oil pressure built up?

If so, you may want to make sure the battery charges to make sure it is full up for tomorrow. Also, the carb's float bowl(s) should be full if the engine has been cranked over...so you should be good.
 
The oil pressure gauge is one of the few wires that still goes through the wire harness to the dash. the other is the water temp. The oil pressure sensor is new.
I did not feel any pressure from the drill, as it is an impact driver and you feel no torque when using them. It just spun wildly fast.
The batterys charge up fast if the sun is out with the two 200 watt solar panels. I get a constant read-out of the battery charge from the solar charge controller.
I will check that the jets are squirting into the carb, hook up water to the outdrive and crank it up!
 
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