I’m running 91 octane in it now. I have to get it cranking first then give it spark or else I get starter kickback and hard start with that much timing

Alright everybody, semi successful day out as we were able to actually run it on the water, the pump being freshly rebuilt with only one trip out since we rebuilt the motor seems to put a big load on it (also had an induced put in, maybe that’s why?) after starting it up and turning up the idle to around 2200 rpm out of the water on the launch ramp id be able to back into the water and it would stay running around 1200 rpm. So we putted it around in the marina at idle and checked timing, it was at about 19 degrees at 1200 rpm. If we tried to give it gas it would sputter and have no power, only after advancing it to around 36 degrees at 1200 or so rpm did it seem to run pretty damn good off idle, this of course means the total timing is something crazy Like 50 something degrees. And also the only way to start it back up after it’s turned off was to disconnected the batt wire from distributor, have my dad crank it, then plug the battery wire in. Any ideas why it would need so much time to run even decent in the water? It wouldn’t even stay running in the water at 16 Btdc. I does have a gnarlier cam than I originally thought and it’s got some big ass valves in the heads.

It did cross my mind that it could be a timing issue but it’s very odd that it would run fine out the water then not at all in the water because of timing being off, given that it doesn’t really have a huge load on it at idle.

I’ll walk you guys through exactly what happens:
I back the trailer in the water to just where back starts floating. I’ll leave to front still hooked up, I’ll start it up, it’ll idle normal for a few seconds, then like shit almost like it’s missing, if I try to give it gas, it’ll stutter and have a total lack of power, if I shut it off or if it dies, I won’t be able to get it started again until I pull it out (just to where it’s out) then after about a minute, it’ll start back up normally out of the water and run fine. If it’s hooked up on the hose at my house it also runs fine. It seems like through the exhaust tips or pump/intake grate being it the water causing a short to the 12v ignition wire, but the wiring is completely intact and that also just doesn’t make sense to me. 

Also it will start and run fine out of the water on the launch ramp on the angle, it’s only when it’s put in the water that the problem happens

The oil looks good still, if it were a bad enough breach that water was getting in the cylinders wouldn’t I be seeing steam? Had a water breach from a cracked manifold on another boat I had and was getting white steam pretty bad out of the exhaust, but the thing still ran great, it was a 460 though, might be different.

It’s idling at around 1200 on the trailer, throttle response is super snappy and sounds mean as hell

It’s not a fuel issue, floats are adjusted correctly and fuel pressure is at 6.5 psi running. I don’t believe it’s a pump issue either since it cranks fine in the water and can’t be restarted once it dies leads me to believe it’s a electrical short but that’s why I’m scratching my head, doesn’t make sense that it would short when touching the water

Holley mechanical pump with regulator and gauge on rail

I’m having a big issue, I got an 85 carrera 205 that will run fine on a hose, but as soon and it’s in the water it runs like total shit then not at all. This is with it on the trailer still just backed up far enough that the pump and exhaust are in. The motor was just rebuilt last month as a long block and hasn’t even been broke in, Heres the specs:
454 BBC roller motor w/mild cam
Weiand intake
Quick fuel 750 dp marine carb
DUI marine HEI distributor (timed 10-12 initial, 34-36 total)
Ac delco plugs gapped at 50
Indmar through transom exhaust
High torque mini starter
Rebuild Berkeley 12JG with ride plate and electronic jetovator

There doesn’t seem to be any wires touching the water or anything when I back it in the water on the trailer, it seems to me like the ignition shorts out when in the water somehow, but I’m completely perplexed on how that could be a thing, I thought maybe the starter is shorting internally causing it to somehow short through the block when the exhaust tips or grate are in the water? I can pull it out on the launch ramp, wait a minute or so, then it runs normally, but the second I back into the water ( even when still running) it idles like shit, has no power and eventually just dies then can’t be restarted til I pull it out of the water. If anyone has any ideas or has been through this before please let me know, here are some pics

Sellin my muscle car project
69 mercury montego
351w with fmx trans
Factory front disc brakes need worj
Centerlines with air shocks in rear.
Has some rust and driver fender damage.
Runs, drives, stops, and sounds mean a hell
$3800 firm

'79 Caribbean 1950 18'