Mercruiser mcm 260 1984

[Winner1984]

I'm having a horrible problem, and i hope someone can help me. I have a 1984 Winner with a Mercruiser mcm 260 sterndrive. It starts great, Runs great on the trailer, runs great in idle and a little above, but when i open her up she runs on top of the water for a minute or two if I'm lucky before she boggs down and then quits. I can start it right back up no problem. and every time she boggs, my distance i can go before it happens again get shorter and shorter. I thought it was a fuel problem and i have now replaced the entire fuel system from the gas tank to the carburetor. It hasn't fixed the problem. I now think its electrical and have no idea what is causing this problem. Does anyone know why this is happening and what i need to fix to stop it?

 

[Scott Danforth]

your probably running out of fuel. go thru your fuel system

 

[greno]

Might be a float issue inside the carburetor. The bowl fills up enough at idle to stay running but when you open the throttle plates and it calls for more fuel the float isn't letting the needle to open far enough to keep up.

 

[kenny nunez]

Try to run it on a 6 gallon outboard tank connected directly to the fuel filter. The only other thing could be the rotor in the distributor which will get hot and go to ground, then restart. I know that sounds weird but it can and does happen . If your engine has the electronic ignition it may just be the module.

 

[wellcraft-classic210]

Have you replaced the fuel filter lately ? If not -- You might want to start their.

 

[Rick Stephens]

Might be as simple as the fuel tank vent being plugged. I see that you went through the system from tank to carburetor. Something is still preventing fuel getting to your engine. I really like Kenny's idea of running off a separate tank altogether.

I can't think of anything electrical that would consistently do this. Have you tested fuel pump pressure? I know you said you replaced everything, but what is 'everything'?

Betwixt everyone here on the forum, we'll get this figured out. A lot of experience for the asking.

Oh, welcome to iBoats forums!

Rick

 

[wellcraft-classic210]

I missed the original post -- agree with alternate fuel source & fuel pressure check.

 

[Bondo]

and i have now replaced the entire fuel system from the gas tank to the carburetor.

Ayuh,..... Welcome Aboard,..... What is the replacement carb,..??

Is the fuel pump, pumpin',..??

Have ya checked the Contents of the fuel filter for anything but clean fresh gasoline,..??

 

[wellcraft-classic210]

Also did the fuel system work include inspecting the check valve in the barbed fitting on top of the fuel tank? They have been known to cause a restriction if debris gets lodged in them and limit fuel flow.

 

[Winner1984]

I replaced the tube going into the tank, all the fuel lines, fuel filter, fuel pump, rebuilt the carburetor. I’m thinking it could be electrical. Distributor, ignition coil, or module. I’m really hoping it’s not the module.

 

[Winner1984]

Thank you all for the welcome and the ideas. I’m stumped b/c I have tried everything with no luck. If I ever find the problem this boat will run like it’s brand new.