Fuel starvation or vapor lock?

[nigel]

My port engine doesn't want to perform when I first start it...

It starts and warms up OK but when I throttle on to get the boat planing it dies off. It will recover if I throttle back. If I rev the engine in neutral it also hits a wall at about 2800 rpm, as if its hitting a rev limiter. Sounds awful too. Much spluttering.

After some minutes this goes away and the engine will run as normal.

I suspect some kind of vapor lock or fuel starvation problem. Anyone else had the same problem?

I'm running twin 4.3Ls (carbs) with Navman 3100 fuel computer and additional standard fuel filters inline to protect the flow transducers (which doesn't actually work as they seem to get blocked every six months or so anyway).

I've had the flow computer for two years now and not seen this problem until a couple of months ago.

Any clues anyone? The boat is a '98 270 Sundancer. Is there an anti-syphon valve on these boats?

Cheers for any help,


Nigel.

 

[capz]

Definitely sounds like fuel starvation but don't rule out a failing coil. I believe stalling and hard warm starting would be a symptom of vapor lock, but I'm not sure.
If it's fuel starvation it's probably carb related i.e stuck float, clogged accelerator circuit. I believe sputtering is a symptom of a lean fuel mix.
Is there hesitation at low speeds, prior to getting on plane?

 

[ylwjacket]

my 98 290 vapor locked. after running, then sutting off, the engines wouldn't start again until they were cool enough for the fuel to condense again. once i shut them off, they were done until they cooled.