3.0L wouldn't run at idle, rebuilt carbs, ran fine, died, will run only at high RPM

Have a 1996 Bayliner 1950 with 3.0 L Mercuriser. In storage for two years, had fully winterized it. Took out on water, ran fine, drove for hour and turned engine off. When I went to re start, it would ony run at high RPM (over 1500). Towed in, rebuilt carbs fully, took every piece apart and soaked in carb cleaner. This was late in the season last year. Re-winterized lst fall, and stored. This spring I started up in driveway with muffs, started easily, idled just fine. Took out on water, ran fine on idle out of harbor, ran speed up, engine stumbled, came back up to speed and then died. Again would not run at idle but would run at high RPM. Gas is two to three years old. I am stumped as to what is causing this problem. Any ideas on what to do next, what to check and in what order?

Thanks

Re: 3.0L wouldn't run at idle, rebuilt carbs, ran fine, died, will run only at high R

Howdy,


Well, first of all, get the 3 year old gas out of there (or dilute it with a LOT of fresh gasoline).

I'll assume that the automatic choke is working correctly? Sounds like the carburetor rebuild might also be faulty.

Re: 3.0L wouldn't run at idle, rebuilt carbs, ran fine, died, will run only at high R

What is the easiest, safeest way to get the gas out, any suggestions, The tank if full- 20 gallons, How do I check the automatic choke?

Thanks for the response.

Re: 3.0L wouldn't run at idle, rebuilt carbs, ran fine, died, will run only at high R

winner155 said:

What is the easiest, safeest way to get the gas out

Click to expand...

A cheap electric fuel pump, switch, some wire, 10-20' of hose, couple of hose clamps, empty gas cans. Remove fuel tank hose from engine's fuel pump and connect the electric pump, route the long fuel hose out of boat to gas cans, wire up switch to pump and battery so you can turn pump on-off outside of boat. Once the electric pump runs dry, raise-lower the bow to see if it will pump out any more.

Now would be a good time to install a water separating fuel filter is the boat does not have one.

Re: 3.0L wouldn't run at idle, rebuilt carbs, ran fine, died, will run only at high R

Thanks, this is very helpful, Any recommendation on water separating fuel filters?