Having an unusual running problem

[Blake71121]

I would like to start out that I am a new Ski NAUTIQUE 2001 owner. My boat is an 85 with the Ford 351 and so far I absolutely love it. I have found numerous threads here and other sites about boats having my same exact symptoms however no one has ever posted how they fixed the issue so here it is again.
My NAUTIQUE runs great at the beginning of the day, after an hour or so of running she begins to sputter and will eventually cut out completely. After it cuts out it is not difficult to start at all, she will fire right back up with a twist of the key, the boat will idle and even let me rev it in neutral. However as soon as I put the boat into gear it will limp and cut out. I've tried giving it throttle in gear and it shuts off right away, if I simply shift into gear and give no throttle it will sputter and cut out after a few seconds. My question is how can I diagnose this issue without throwing a ton of money replacing parts? I do already have a newer electronic ignition on the boat. I plan to replace the impeller as general maintenance but I am not sure this is an overheating issue? Some have said possibly a fuel issue or vapor lock but I wouldn't think the boat would idle or rev in neutral if this was the case? Any advice at all is greatly appreciated!

[EchoLodge]

Not sure if your boat has a similar fuel line elbow like my old 90 Sport but its worth a look. Mine had a screen on it that would first only starve at WOT, but as it continued to clog it got worse and worse. Found the issue after replacing lots of parts I didn't have to. Its been a long time but I believe the elbow sat on top on the fuel tank.

[surroundsound64]

Ignition issues are common on these old boats. There are conversion kits to rid your boat of the points setups with mixed results. I finally got tired of going back and forth and put a Davis Unified Ignition system in mine and love it!

[t.franscioni]

Sounds like a neutral safety switch issue on the transmission. Not familiar with how those older nautiques are setup but if it has a neutral safety switch I would look at that and replace it.

[beachdude24]

Hi I own a 1986 sn 351w ok it seems you might have 2 problem it might be carb issues or ignition problems... First check the carb if its overflowing when you put it in gear if so open the primary bowl clean check for debris in the bowl needle seats or check if the float needs adjustments maybe. If the carb is in good working order check your ignition system I'm still using points condenser.. Maybe you are having a bad rotor in your distributor

[s_kelley2000]

Not sure if your boat has a similar fuel line elbow like my old 90 Sport but its worth a look. Mine had a screen on it that would first only starve at WOT, but as it continued to clog it got worse and worse. Found the issue after replacing lots of parts I didn't have to. Its been a long time but I believe the elbow sat on top on the fuel tank.

I believe this anti-siphon valve is the part you are referring to:
http://www.nautiqueparts.com/elbowpi...phonvalve.aspx