Engine stalling out at low RPMs

[Rkells78]

Hi everyone first post.
This summer my dad gave me his boat and once I drove from Arizona to Indiana to pick it up I found out that he did not take the drain plug out. The boat was winterized and left in the driveway from April to May but the cover failed and water got in the boat. It flooded the engine and the water got to spark plug level. So the over the past few months I have changed out the starter, impellor, thermostat, wires, plugs, fuel pump, oil, fuel water separator, solenoid, new battery, sandblasted and repainted the intake manifold and rebuilt the carb. I got the boat going and it surprising goes good. To get it started though I have to have the engine in neutral with giving the engine gas. Sometimes I have to give it starting fluid but it will go at full speed. It will not start in dead neutral and if I lower the speed to much it will stall out. This becomes a problem when launching in no wake zones and trying to have control at low speeds to get it back on the trailer. When pulling wakeboarders and trying to pull them up it will also lag for a second. I will have to have it in neutral at higher rpms and quickly throw the boat into gear to get it going. What can I do to try and fix this? I am going to the lake tomorrow to try and adjust the carb idle screws and chec vacuum reading but other than that I have no other ideas.
It is a 1989 Ski nautique with a ford 351w 5.8 engine and a holley double barrel carb.

[NautiqueJeff]

Carb should be a Holley 4160 marine 4-barrel. Are you sure it is a 2 barrel? If it really is, at least make sure it is a marine carb, or you risk a fire.

First, you should check the timing to make sure that is set right. Should be either 6 or 10 degrees BTDC at 600 RPM, depending on your distributor. Once that's set, move on to adjusting the carb.

With engine off, screw in both idle air mixture screws until they lightly bottom out.

Screw out both idle air mixture screws by 2 full turns.

Start the engine and adjust idle speed set screw so engine idles at 650 - 700 RPM in gear.

After it is running at normal operating temperature, you can fine tune it. Turn both idle air mixture screws in (clockwise) 1/4 turn at a time and monitor the engine RPM. Always adjust both screws the same amount. Repeat until you hear the RPM drop, then turn both screws counter-clockwise 1/4 turn. Clockwise will lean the idle mixture, counter-clockwise will richen the mixture.

Readjust the idle set screw (if necessary) so that the engine idles at 650 - 700 RPM when in gear.

[Rkells78]

Sorry i meant double pumper it is the 4160 with electric choke. I tired to upload some pictures but they were to big. I don't think I can get the engine to idle without dying to be able to adjust those screws. can I do it in neutral with higher rpms.

[Rkells78]

This is the carb. Would I pull that rubber piece of above the transfer tube line to hook the vacuum gauge too?

[NautiqueJeff]

Nope. That's before the venturis of the carb, and you need the vacuum reading after. If you try to use that port, you'll likely get ZERO vacuum. Most 4160 carbs don't have the vacuum port needed for this procedure, so that's why I gave you the rpm-based procedure above. Some 4160 carbs do have the vacuum port needed, but it is low down on the carb, right above the base gasket. I have never had one that actually had the port though.

[Nautiquehunter]

Are you still running points? Start with the basics new points adjusted to 30 degrees dwell , set the timing then adjust the carb.

[Rkells78]

Sorry can you explain what running points mean? Learning a lot of this stuff on the fly