Ford 302 issues

Jakem

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Apr 25, 2021
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I was hunting wires and following my manual. It shows white from harness to electric choke...my white wire went to coil negative. Not sure why
 

Jakem

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Apr 25, 2021
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As I was cleaning and replacing terminal ends behind dash I found the amp had no ground
 

Scott06

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I haven't got a tester so I will take it and have it tested. I followed a vidio on how to test with voltmeter and it shows up good
I would take the Volt meter and gap tester out on the water. When/if it happens again use them to rule out if this is spark or fuel related. Thinking with your other electrical stuff going on if you are getting a voltage loss leading to spark strength loss? Just swag from keyboard view ...
 

Jakem

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If the ground for amp meter comes off tach gauge then I have found it..as there was one
 

Jakem

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Should be 13+ V


Was the battery connected at the time?

The regulator is cycling trying to balance output with demand.

Bad alternator /voltage regulator
Battery shorted internally
Fairly large parasitic drain
Bad battery cable
I now have 14.6 at battery with boat running
 

Jakem

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Hand held...now that I have cleaned all connections behind dash and added a direct ground from battery to ground busbar behind dash it doesn't read like it's high on dash.meter...seems all good for now..find out when I head to water
 

Scott06

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There was also a few loose connections back there
On my boat the ignition on circuit daisy chains from the switch through the gauges on its way back to the engine… dumb way to do it in my opinion. what you have found may be your issue
 

Lpgc

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I have a 96 Four Winns with Ford 302.

When I bought the boat the owner sent me a video of how to start the engine, had to flick an accessories switch on the dash or it wouldn't crank. I thought someone had fitted an immobiliser but when I dug into it I found there was only 9v at the coil from the ignition key. The start solenoid also gets power from the dashboard and the 9v wasn't enough to energise the start solenoid... which is why it wouldn't crank unless the other accessory switch was flicked (someone had connected the accessory switch to bypass the ignition key, no immobiliser was fitted). I found the problem to be a voltage drop across the dead man switch so I bypassed the dead man switch and now it will start just on the key and there is 12V at the coil. Another win from fixing the voltage drop is that the alternator voltage sense wire is connected to the ignition on wire from the helm... Before I fixed the voltage drop the alternator was seeing battery voltage at 9V so was charging at it's full capacity all the time and overcharging the battery.

My gauges are car style and they were all broken when I bought the boat, it was as though they all read too high even with ignition off. I fixed the gauges by simply taking the needles off spindles and putting them back on in the correct position but I think the gauges will have been broken because at some time there was a bad earth to the helm, combined with that 3V voltage drop on the purple wire this could have seen all the gauges get -3V instead of +12V and spun the needles anticlockwise on the spindles. Or someone connected a battery wrong polarity but I would expect that to break the electronic ignition too (which it might have done but my distributor etc look original).
 

Jakem

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I went out yesterday and this problem is still going on. Revs up fine in neutral but under load no way...I fished for a couple hours and had to go back to doc just idling...
 

ratdude747

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Sep 30, 2023
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I have a 96 Four Winns with Ford 302.

When I bought the boat the owner sent me a video of how to start the engine, had to flick an accessories switch on the dash or it wouldn't crank. I thought someone had fitted an immobiliser but when I dug into it I found there was only 9v at the coil from the ignition key. The start solenoid also gets power from the dashboard and the 9v wasn't enough to energise the start solenoid... which is why it wouldn't crank unless the other accessory switch was flicked (someone had connected the accessory switch to bypass the ignition key, no immobiliser was fitted). I found the problem to be a voltage drop across the dead man switch so I bypassed the dead man switch and now it will start just on the key and there is 12V at the coil. Another win from fixing the voltage drop is that the alternator voltage sense wire is connected to the ignition on wire from the helm... Before I fixed the voltage drop the alternator was seeing battery voltage at 9V so was charging at it's full capacity all the time and overcharging the battery.

My gauges are car style and they were all broken when I bought the boat, it was as though they all read too high even with ignition off. I fixed the gauges by simply taking the needles off spindles and putting them back on in the correct position but I think the gauges will have been broken because at some time there was a bad earth to the helm, combined with that 3V voltage drop on the purple wire this could have seen all the gauges get -3V instead of +12V and spun the needles anticlockwise on the spindles. Or someone connected a battery wrong polarity but I would expect that to break the electronic ignition too (which it might have done but my distributor etc look original).

If the OP's 302 is like the Mercruiser 888 (302 based) in my 1976 Starcraft, the alternator is a factory-modified (1-wire) Delco-Remy 10si. No external voltage sense.

Under load with engine off I do get substantial voltage drop to the gauges, confirmed by a GPS speedometer with voltage reading that I wired to the otherwise disused accessory post of the ignition switch. I get battery voltage (12.6V) on accessory, but ignition on, 11-10V. Wiring is in good shape too (as far as I know), so that's just how these things are I guess. When running (with a rebuilt alternator and a different 1-wire conversion installed) I'm getting 13.5V idle and 14.1V running; I'll have to recheck the Mercruiser schematics but that makes me think the alternator is charging though the ignition (hence the lack of drop when running).

The boat's old points ignition had failed when I was gifted it, so I upgraded to a pertronix Ignitor setup (tapped power from the white choke heater supply, where the ballast wire used to connect). Other than having to retime it (it moved timing a good 10 degrees or so), it's so far been a good setup and something I'd suggest to anybody with this engine who is considering such. On the old setup, it's suspected the ballast wire failed (but I didn't want to mess with it since better things exist these days).
 

Scott06

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I went out yesterday and this problem is still going on. Revs up fine in neutral but under load no way...I fished for a couple hours and had to go back to doc just idling...
So when this occurs do you have strong enough spark on a gap tester. Need to figure out if this is spark or fuel related.

it doesn’t take any power to rev up in neutral It is kind of a meaningless test.
 

Jakem

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Apr 25, 2021
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Can you suggest a decent spark plug tester and I will order it and give it a shot
 

Jakem

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I terminal on 4 post starter soliniod has no power with key on or started.
 

ratdude747

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I terminal on 4 post starter soliniod has no power with key on or started.
It's not supposed to. The idea is that when cranking, battery voltage is going to be low, so the ballast wire/resistor needs to be bypassed (provide full battery voltage to coil) so the coil has enough juice to fire. When not cranking, it's open, allowing the ballast wire/resistor to modulate coil power so ignition doesn't burn itself down at 14V.
 

Jakem

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So here's what I'm dealing with...pertronix ignition...flamethrower coil 0.6 ohm..and 4 post starter soliniod.. I have white wire hooked to positive coil and dizzy pos...and I terminal pos on coil...brown and coil black to negative...is this correct
 

ratdude747

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So here's what I'm dealing with...pertronix ignition...flamethrower coil 0.6 ohm..and 4 post starter soliniod.. I have white wire hooked to positive coil and dizzy pos...and I terminal pos on coil...brown and coil black to negative...is this correct
I didn't bother with the I terminal since on Pertronix there's no need for a ballast wire and my ignition switch energizes "RUN" during start (not to mention my starter circuit is completely different from stock). If your ignition switch doesn't energize "RUN" in "START", then you will need the I terminal wire to power the ignition during start.

If the white wire is a ballast wire, then snip it and re-source from the choke heater white wire directly (my ballast wire was light tan). But otherwise, yes, white and pertronix red to the + terminal on the coil (and the I terminal wire if needing such), pertronix black and tachometer/shifter kill switch wire to - terminal on the coil. Ignitor module grounds from the distributor body.

I assume you checked your base timing at idle (10 degrees BTDC). I had weird issues because my timing was way off after swapping the module.

Not specific to Mercruiser, but if the crank pulley has a harmonic balancer, the rubber can go bad and cause the timing marks to no longer be accurate (would need to see if actual TDC matches timing mark TDC).

Finally, it's possible the weights in the distributor are seized/tight and aren't advancing timing when revving up (as while marine distributors don't have a vacuum advance, they do have RPM advance).
 

Scott06

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Can you suggest a decent spark plug tester and I will order it and give it a shot

this is the one I use. Bought it after fixing and old outboard that had two bad coils. Spark looked ok holding a plug … rebuilt carb, fuel pump still would miss, ohmed the coils they were bad. so now I start with this tool first …

I think you want to see the spark when it’s running ok and when it is acting up see if there is a difference. Seems here and on the gto forum a lot of guys have intermittent issues with pertronix. Might be worth swapping a set of points back in for a sanity check

did you bypass the ballast when you put in Petronix
 
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