06 225 pro xs cranks no fire

[Soko]

06 Mercury 225 pro xs 1B387787
1st time out this year from storage so I added quickkleen like I always do to the small amount of fuel left in tank from last fall with stabilized fuel. Added 15 gallons of fresh fuel. Backed into the ramp to start motor. I have a key pad instead of key. I entered my code and pushed start to activate the pad I heard the normal beep and fuel pump cycle. I pushed start and it fired but didn’t start. I checked fuel bulb and it needed 3-4 squeezes until it was a hard bulb. Pressed start and it fired but didn’t start. I pushed start again and it would crank but no firing.
So I went back through my normal sequence and realized I had no beeping, no fuel pump sounds and it cranks but no firing. So I put it on the trailer and headed for the barn.
First thing was to check the 4 fuses on the motor and all 4 are good, swapped the relays to be sure the first towards the back (fuel) was working. All good. I have a brand new 1000 MCA cranking battery but to be sure I put a charger on the battery and topped off the charge. Still no beep or fuel pump. I replaced the MAP sensor with a borrowed working version no changes but when I unplugged the sensor I got a constant beep until I turned off the master power. So I know the beeper still works. I took out the fuel filter and it was clean with no particles or foreign material found.
I also checked and flipped the kill switch several times with no changes. I then went under the console and went through all the connections I do have analog gauges so I was sure to check that connection with no changes. I unplugged the key pad and have one of the 4 connections with 12.8 volts going into the key pad. The pad lights up and cranks the motor like its fine just no fire!

Thoughts on what might be my culprit??

Thank you in advance for any and all suggestions.

[JOE54]

no beep ,no pump activation = no power to pcm or main harness , check all connections from key switch harness inspect terminal connections on main power relay plug , been there seen that

[EuropeanAM]

+1

Also need to sample the fuel. Phase separated fuel or WATER will not permit the engine to run or start properly.

Beyond that, have to check the basics: Compression, Spark and Fuel Quality/Delivery/Air-Fuel Pressures/Air-Fuel Pressure Leakdown at 5/10/15 seconds.

[Soko]

Update: I checked and confirmed I have spark, compression and can’t generate any air pressures without starting the engine? Or can I check them while cranking the engine? But since I have compression and spark it seems it should be fuel!
So, I disconnect from the onboard fuel tank and hooked to a 6 gal can from a 25hp as a temporary tank.
I drained the fuel reservoir on both sides and took the top off. I took both fuel pumps out and tested them with 12 volts and both started right up. What I did find was some thick nasty green algae covering the screens on both pumps and a deteriorating rubber gaskets and O-ring. I also found the fuel pump on the bottom had a broken connector on the positive side and was only getting the ground I’m fairly sure. I repaired the wiring and got most of it put back together when I decided it was time to call it a night.
I could not get a 12 volt reading at the fuel pump wiring when I signed into the keypad but without fuel in the first reservoir for the sensor I’m not sure the ECM would send the voltage to start the fuel pumps. That is strictly my opinion and not founded on any real knowledge of Mercury Optimax engines. However, it makes sense to this brain. So once I get it all back together and good quality fuel flowing I’m hoping to hear that beep and the sound of the fuel pump once again when I sign in to the keypad.
Any thoughts?

[JOE54]

my thought= no sensor that tells pcm theres fuel in vst just water ,no beep no = no start , you need to eliminate key pad and boat wiring as source of problem

[EuropeanAM]

Fuel pumps only run for a couple seconds at key-up (and then shut down until an RPM signal is noted).

[Soko]

I ordered a 3 position key switch to replace the key pad. I had the 14 pin connection apart and had 12.4 volts on female A and male C not sure if that’s normal or even matters, but trying to add as much detail as I can. When I started putting the 14 pin back together I heard the fuel pump start a cycle but as soon as I started to rotate the locking ring the fuel pump would stop. If I just held it in the same position when the pump started it would run what seemed like a normal cycle. But it still wouldn’t fire and no beep. Later in the day I was under the dash trying to sort and find all the connections show on the 14 pin connector diagram I heard the horn make a very small and not at all the normal volume of the beeps when I started up the key pad to check for voltages. Again….maybe nothing but I’m trying not to assume anything.
If the kill switch was defective would I have spark? If the neutral sensor was bad would I have spark?

[JOE54]

no /yes but mtr wont spin over

[EuropeanAM]

Keep in mind that if you're only plugging in a switch to the harness (like the pad was)- you may still have a problem in the control module that's used in many of these boats.

I personally prefer a transom-mounted (test) keyswitch and harness assembly, plugged straight into the engine. Then you know for sure it it's a "boat side" problem, or an engine or battery supply problem.

[Soko]

Makes sense. I saw a 2 ft 14 pin harness for testing. Is this what your referencing?.

[SilverFox579]

Yes.

[EuropeanAM]

Provided it has the keyswitch and warning horn mounted in a little box: Yes sir!