TOPIC: Need help with diagnosis

Hi

I am running a merc 400 that is new to me 1961...

It has been rebuilt, clean carbs, etc.

After we adjusted the idle speed, we ran the boat for an hour up to at most one click less then full speed.

It e
Was great, good power, all fine

Then on the home stretch I had an area with no waves and did the extra click, full throttle. Went well for 10 seconds and then. Pfrrrffffffff prtrtrtr.... Stop

I checked everything, nothing seemed wrong. I started the engine again, no problems. Ran fine.
When I put it in gear it kind of rev's up a little, but it takes two clicks forward for the engine to realize we want to go faster, and then it never rev's up ... It just sputters, sounds like it's not getting gas or the timing is off a lot.

Can anybody give me a hint what could be wrong?

Cheers

From the description I've had these problems.

Water in the gas always acts like something much worse.

Gob of dirt in the main metering jet.

Carb float hanging up or too high or low.

Flooding can act like starving. More fuel isn't always the answer.(trust me)

If you say rebuilt, I assume they put all new fuel lines that don't mind alcohol. Otherwise you could be having hose garbage in the fuel system.

Good luck.

Keep us informed.