Merc 4.3 fuel pump power/wiring, carb ?

[wood45s]

Merc 4.3 fuel pump power/wiring, carb ?
1995 Starcraft Islander 221 recently purchased.
It runs good once cranked. It?s a little hard starting when cold, but cranks good after the first start. I drip a few drops of gas in the carb and cranks immediately when cold. Choke is closed. Carb is a Weber 4barrel. With it not running and I take the throttle cable off and pump the throttle lever there seems to be no extra gas squirted in the throttle bores. Is this normal? Or maybe I have an accelerator pump problem? Merc manual says the pump should have 7/16 inch stroke. I?ll have to check that tomorrow.

Concerning fuel pump ? the Merc book shows a purple/yellow wire connected to the starter solenoid along with the yellow/red wire. The purple/yellow wire is not hooked up. I?m not clear on this, but thinking maybe that purple/yellow wire needs to be hooked up and provide power to the fuel pump while the starter is activated? I don?t yet fully understand the wiring between solenoid, slave solenoid, starter and ignition switch.

Thx,
wood

 

[Bt Doctur]

that wire comes from the outermost small lug on the starters solenoid. supplies power to the fuel pump during "cranking" only
With the carb bowls full, there should be a healthy squirt of fuel when moving the throttle plate

 

[wood45s]

Thank you BtDoctur. Both answers as i suspected. I'll probably get a kit and check the carb, floats, all settings/specs, etc. probably during the winter. I will probably look for oem Merc kit.

thx

 

[Bondo]

Carb is a Weber 4barrel. With it not running and I take the throttle cable off and pump the throttle lever there seems to be no extra gas squirted in the throttle bores. Is this normal?

Ayuh,.... Welcome Aboard,.... Not normal, but common,....

The float bowl in these carbs are known to leak off into the intake,....

 

[Jcris]

I've got a 4.3LX with a 2 barrel Mercarb that shows very similar issues. If mine sits for a couple days the float bowl will drain completely. When you give it throttle to prime for starting no fuel gets to the carb. My workaround is a momentary switch to run the fuel pump prior to starting. This has resolved the hard cold start issue. Why doesn't that fuel pump run/cycle in the start position? Fuel injected motors cycle the pump in the start position , why not with a carb?

 

[Rick Stephens]

I had the same type of issues with carb emptying itself if left for a few days. I added an inexpensive brass check valve between fuel pump and fuel filter. My new at the time Weber/Edelbrock carb was obviously bleeding back down to the fuel tank. Now two quick pumps of the throttle always starts and I have the choke plate adjustment set to nearly off.

Hooking that wire up from the outer lug on the starter to the hot lead to the pump will help as well.

Rick