3.0 Mercrusier/OMC 88 bayliner Electrical gremlin?

[88 bayliner ss.hooptie]

alright so im pretty much at my wits end and figured its time to ask for help.
Replaced-
spark plugs
igniter (Petronix 1145a kit)
little round magnet sits around distributor shaft so the igniter can read
rotor
neutral safety switch
starter
serpentine belt
replaced ignition coil
checked all fuel components-checked with starter fluid to make sure
checked for spark-good spark
compression-good
bypassed fall off boat switch-no changes
So what it is doing is not wanting to fire up. I have confirmed with a timing light on all wires that there is spark going to each cylinder. i will add the boat was working fine until this random problem came about randomly. shut it off for a swim with the kids after a 10 min ride into a cove where it is about 6ft deep and then it wouldn't start after that. I am totally lost at this point. I even tried to rotate the distributor around thinking the timing may have been off (tid bit from the previous owner) Is there something that I am missing? It does not have points it was converted to electronic ignition. ive double checked firing order, 1342, and wires are going to the correct spot.

 

[alldodge]

Did anything happen when you used starting fluid?

 

[Bondo]

Mercrusier/OMC

Ayuh,..... Welcome Aboard,..... It's one, or the other, Not both,......

So which is it,..??..??

 

[88 bayliner ss.hooptie]

okay so update. the timing was way off, about 120* off on the dist. found out the old magnet ring was missing magnets (not sure how it was working and probably the cause of the timing being so far off from the previous owner) and found that the fuel system keeps losing prime. It does have an after market electric fuel pump that has supposedly been on the boat for a few years with no problem. (I do understand the dangers of external electric fuel pump and boats) so i vacuum tested the fuel line and its not losing pressure anywhere. This could have been the gremlin ive actually been looking for. When i pumped the carb i saw fuel inside the carb but i guess that was just from the bowl? and yes when using starting fluid it will fire momentarily, i also rebuilt the carb last night no improvement. i going to get a new water separator filter tomorrow but it didn't have any water in the filter when i put it in a glass jar. the current fuel pump will do 36gph and 4-7psi model number is 17301 but when i use a vacuum pump to get fuel to the carb and prime it, it will lose prime and the pump tone changes ( like its lost prime.

 

[alldodge]

Antisiphon valve maybe?
The valve is a barbed fitting that the fuel line connects to the tank. It has a spring and check ball inside and can get clogged up and make it real had for a pump to suck thru it

 

[88 bayliner ss.hooptie]

welll....the problem kind of took care of its self. the engine vapor locked and i cant get it freed up. i think i set the timing too far back and killed it. i guess 30 years is a good run for an engine that seems to have been abused most of its life.

 

[alldodge]

Sorry to hear but vapor locking doesn't stop a motor, it just keeps cranking but does not start

If its locked up tight, then water got in or way to much gas. Could pull the plugs and crank over to see what belches out