I bought a 28 year old boat and have been working through ALL the issues. So far I have replaced the slave solenoid; fixed improper wire connections including running the fuel pump through the relay that had at some point been bypassed and run to a manual on/off switch on the dash instead; new battery; new battery cables; new battery selector switch; new spark plugs (ACDelco MR43T) - wires are on order (Sierra Marine 18-8801); reset the electric choke that was stuck in a fully open position. I have made sure I’m getting spark at every plug location (set plugs to chart gap of .035). I checked the fuel system; fuel is clean, I get fuel to filter, through the filter, to the pump, through the pump, and to the Holley 2BBL carburetor fuel inlet; fuel sprays when at WOT to prime. I’ve reset the curb idle screw and the idle mix screws to the base settings. She’s currently in my driveway with the lower unit submerged in a tank with water above the inlets.
So here’s the problem(s). Yesterday I got her to start up and idle at ~600 rpm in neutral for about 10 seconds, several times. Smoothest, best sounding idle without any lurching or chugging in the whole ~3 weeks I’ve owned it. But then she would die out. No rev-up before dying, very little smoke (both improvements over what she was doing before). Pulled the plugs (pretty sure they were the wrong plugs), and they were all fouled. Cylinder 6 dumped a bit of gas when I pulled the plug. So I figure I’m getting too much fuel/not enough air. Adjust the curb idle screw to try to get higher RPM, wouldn’t turn over, so I adjusted it back. Did the same thing - starts, runs great at a ~600rpm idle for a few seconds, dies. I notice that it’s also dumping fuel into the oil because is starts bleeding out of my dipstick from the pressure build up. I again assume this means I’m getting too much fuel and it has nowhere to go, so it just drains into the oil
. At some point she just stops turning over. Cranks, but bogs down in rhythm, so I assume it’s an issue with one of the cylinders maybe not getting spark? Or maybe a compression issue (that I don’t have the tools nor the knowledge to test). Probably cylinder 6 since that is the one that seems to accumulate fuel every so often? (Or is that because the boat is parked on an incline, and cylinder 6 is the furthest back therefore the lowest)? I can pull the plug on 6, place on the block to ground, in the wire, and it sparks in sequence without bogging down like it does when it’s installed. She now just refuses to actually turn over. Sounds like it’s putting strain on the starter when it bogs.
Ignition wiring setup: NEG cable grounded to block. POS cable goes to battery selector switch; then to slave solenoid; then to starter solenoid. All other wires have been run to match schematics I’ve found through this iboats. EXCEPT, the cable from the slave to the starter solenoid has another, smaller wire running from the slave to another post on the starter solenoi; instead of one wire from slave to starter solenoid, then a jump wire on the starter solenoid itself. Not sure if or how much of a problem this is, since it had been turning over fine
.
I am running out of patience, money, and motivation. The seller got her to fire up and run for a bit (trailered) by activating the “fuel pump switch” on the dash, and putting it in gear to idle at ~1,000rpm. Knowing literally nothing about boats at the time, I believed him when he said that was normal
. So yes, I got taken for a ride and I’m sure he laughed all the way to the bank, and here I’m stuck with a boat that doesn’t run, and I’m running out of summer. I don’t know what to do next to try to fix it.
So here’s the problem(s). Yesterday I got her to start up and idle at ~600 rpm in neutral for about 10 seconds, several times. Smoothest, best sounding idle without any lurching or chugging in the whole ~3 weeks I’ve owned it. But then she would die out. No rev-up before dying, very little smoke (both improvements over what she was doing before). Pulled the plugs (pretty sure they were the wrong plugs), and they were all fouled. Cylinder 6 dumped a bit of gas when I pulled the plug. So I figure I’m getting too much fuel/not enough air. Adjust the curb idle screw to try to get higher RPM, wouldn’t turn over, so I adjusted it back. Did the same thing - starts, runs great at a ~600rpm idle for a few seconds, dies. I notice that it’s also dumping fuel into the oil because is starts bleeding out of my dipstick from the pressure build up. I again assume this means I’m getting too much fuel and it has nowhere to go, so it just drains into the oil

Ignition wiring setup: NEG cable grounded to block. POS cable goes to battery selector switch; then to slave solenoid; then to starter solenoid. All other wires have been run to match schematics I’ve found through this iboats. EXCEPT, the cable from the slave to the starter solenoid has another, smaller wire running from the slave to another post on the starter solenoi; instead of one wire from slave to starter solenoid, then a jump wire on the starter solenoid itself. Not sure if or how much of a problem this is, since it had been turning over fine

I am running out of patience, money, and motivation. The seller got her to fire up and run for a bit (trailered) by activating the “fuel pump switch” on the dash, and putting it in gear to idle at ~1,000rpm. Knowing literally nothing about boats at the time, I believed him when he said that was normal
