Will start Cold/ Won’t Hot

My bet is trash in the carb is not letting the needle valve seat. With the flame arrestor off while idling, see if gas is dripping into the carb throat. After the boat sits a while the fuel pressure bleeds off and the fuel in the carb and intake evaporates and lets the engine start normally.

That's my theory. (Actually I had the exact same thing happen on my '68). I had to clean and rebuild the carb. The fuel bowl had a lot of fine redish powder-like flakes in it. I had to add an inline fuel filter to resolve the issue.

Then again, it could be your igntion coil. A failing coil will behave the way you described.

Tim D, no water on the plugs. The plugs are dry and white. Look like brand new. No, it does not crank slower.

Jim in Houston, can I check the coil or just buy a new one?

when it isnt starting you need to determine if it isnt getting fuel or spark. the you can go into your trouble shooting tests to determine what needs replacing rather than just throwing parts at it.good luck

I'm having the same issue w/ a 91 Correct Craft w/ 351 Ford. Getting gas, probably not spark. My distributor,rotor & points are solid state. If it's a coil problem wouldn't the engine quit running when it got hot?

I had the same problem. Replaced all of the ignition components. Converted to Pertronix and put on a new carb after several failed rebuilds. It stopped for a season and I thought my worries were over. Started it up this season and all came back. Started to really dig around in the ignition and found that I was getting a low voltage to my coil when cranking. This is probably due to several things and probably was the culprit all along. One of them being the boat is 20 years old and resistance is building in the wiring harness, and the starter is getting old and drawing more and more amps when cranking. Anyway I got a great tip from the I/O Mercruiser guys at www.Iboats.com. Take a heavy guage wire and run it from you empty stud on your starter solenoid up to your coil. When it will not start touch the wire to the "+" stud on your coil. If it starts then you have figured out your problem. This jumper allows a full 12 volts to run to your coil while cranking and when the starter solenoid disengages then the typical current then runs through your ballest resistor to you coil dropping the voltage to about 7-8. If you put on electronic ignition make sure you talk to the techs and hook it up the way they say, not necessarily the way the instruction say. My Pertronix is hooked directly to a keyed 12 volts no the coil. They need at least 8 volts to trigger (wich I was not getting) Anyway a 20 cent wire fixed a problem that about $500 worth of parts did not.

Jason,
Thanks for the info. I have coil packs and not just one coil, so not sure how to apply your solution to see if I'm not getting enough volts there? The more I dig into this, the more it sounds like I need to convert the whole ProTec igntion.