I recently purchased a boat with above engine (staight-6). I ran it about 6 hours and all was perfect - hummed right along, quick response. Every time I added gas, I would first put the oil in (mixer is removed, so I manually mix the 50:1 myself), then add the gas. The last time I fueled, I did not add the oil until a couple of days later. After adding the oil, the boat/motor sat for about 2 days until the big fishing trip. Attempts to start the motor (with throttle in neutral failed. The only way I could get it to start was to throttle up, and then start it. No problems starting it this way. It would only rev up to 3000 if I was lucky, but at full, it generally stayed around 2. As soon as I'd slide the throttle back, it would die before I could engage the prop.<br /><br />I suspected bad gas, so got a small tank, mixed up some fuel, and first ran out the gas in the motor. This did not make a difference. I then replaced the bulb and hose between the gas tank and the motor. Where I was not getting a solid bulb before, I am now. I could now idle down to just above normal idle, but as soon as I slip it into "neutral", it would hesitate, and die.<br /><br />I purchased a can of Sea Foam, and removed the cowling, and shot a fair amount into the carbs (3 of them). I also pulled the plugs and put a bit into the cylinders. I ran it again, and then pulled and cleaned the plugs.<br /><br />I've also tried increasing the idle speed screw, but don't think this is what I need to do. For a while (short) - after doing all this it would idle for about a minute in neutral before dying.<br /><br />Is there anything else I can check? The motor came out of a tune-up in July (before I purchased it). The plugs look new. The motor sounds great at any RPM above idle, and I've also replaced the in-line fuel filter.<br /><br />Thanks,<br />John
<br /><br />Also put a inline fuel/water filter between the bulb and tank.<br /><br />Took the boat out after running it with flush kit on it. I could get it to start just fine, but max power yielded about 4K RPM, enough to get high on bow, but not enough power to plane. I adjusted carb mixture on water to yield max RPM.<br /><br />If in neutral, I could get RPM to over 5000. But putting it in gear would give 4000 best and not the power it had last week.<br /><br />I checked fuel pump and it appears to eject fuel just fine (during cranking, I get solid squirts.<br /><br />Sooooo.....<br />-new "crappy" little fule filter<br />-new gas tank to engine hose (with bulb)<br />-rebuilt carbs (all three)<br />-verified fuel pump ok<br />-can hit 5000RPM with prop not engaged<br />-max WOT RPM (prop engaged) is just under 4000, but no power to hit plane<br /><br />It does not sound like engine is missing, and initial test showed I had too little mixture (would die when I maxed the throttle.<br /><br />What would be the next thing to check? How do I check for each plug firing?<br /><br />Thanks,<br />John