Hello all!
I recently purchased a 1977 CVX 18 that hadn't ran since last fall. It has the original Mercruiser 188/888 302. All the fluids in the motor and lower unit are good, had it looked over by a member and a boat mechanic friend and they basically gave their blessings for sea trials. It has a brand new Holley 2 barrell 350 CFM carb on it, that could probably use some tuning.
Boat fires right up and runs great. Coolant temps run in the 140F at speed, 155F when idling/low speed after warm up. Checked this with a laser temp gun on the risers and temp sending unit housing on the intake manifold.
Twice now about an hour into a river ride, the boat has stalled out and won't restart, had to be towed off the river. However it will fire, then die, if you spray carb cleaner down the carb, so there is still spark. I put a brand new fuel filter on it after the first time, confirmed I can easily pull fuel from the tank with a hand pump so the pickup shouldn't be clogged.
When the stall happened both times it was exactly the same condition. Engine was fully up to temp, had been WOT several times with no incident. After 10-15 minutes cruising in gear just above idle, it would die and not refire. I'm concerned it's heat build up causing vapor lock. My thoughts are to try keeping the engine cover open anytime I'm in that condition to allow engine bay heat to escape.
Besides actually getting the carb tuned, does anyone have experience with this, or an educated opinion given the symptoms? I'm going to change the wire/plugs/distributor cap this week just to eliminate any issues there as I have no idea when it was done last so it can't hurt and they're inexpensive and easy to change.
Thanks ahead of time for any help!