Boat stalling at idle....

[Elliott Brown]

Someone help please!!! I have a 1989 211 Mirage Trovare BR w/ 350 small block that is having issues at idle. I have had the Rochester Quadra jet 4bl carb rebuilt once and have purchased 2 remanufactured ones and I am still having issues. The boat will cruise perfect at cruising speed, but when I drop the throttle it will briefly stall (when switching over to the secondary?s). Then when I return to idle speed it wants to die on me completely. I've had the boat looked at by a professional and he says I still have a junk carb on it. The company I've purchased the carb from told me no way it?s related to their carb (second one they sent me). The mechanics told me the idle adjustment screw is doing nothing for the carb and it won?t adjust properly.

My question is, what can this be beside a carb? I'm going to try and throw on the thicker gasket that sits between the carb and the manifold to see if that makes a difference. The carb guy told me I may have a vacuum leak.

I feel like the carb is dumping too much gas and it is flooding out. After running it for a bit I will have to feather the throttle in order for it to start again. Any chance this is some type of ignition issue? Should I try replacing the cap, wires, and plugs?

On a side note, the fuel pump was tested for the correct pressure as well.

Any help is greatly appreciated.

Thanks!

 

[Don S]

Re: Boat stalling at idle....

When your previous rebuilds and replacement carbs were installed, did you readjust the idle mixture screw? What is your idle rpm?

Is your timing set to specs?

 

[Elliott Brown]

Re: Boat stalling at idle....

Yes, i did readjust the idle mixture screw. The boat is idling around 800-900 rpms, any less and it will stall. I did take the plugs out today and they are completely black. I'll try new ones, but I'm affraid they will look the same after i take it out a couple times.

 

[Don S]

Re: Boat stalling at idle....

It should idle easily at 600 to 650.

You didn't answer my question about the timing.
Does the choke open up?
Might hook a vacuum gauge up to the intake and see what it's doing.
Spray some carb cleaner around the carb base and intake manifold ports where they bolt to the head and see if you have a leak. The spray will make the engine change rpm if it leaks.