Carb 210 Engine Slow to Start after sitting

[drxlcarfreak]

My engine normally is typically slow to start between trips, usually about a week in between, which I knew when I bought the boat, no biggie, I just run the starter for 5 seconds twice at the dock to refill the bowls and then it'll start up. Recently it has been hard to start with even an hour or two in between starts, which actually left us stranded yesterday because someone left the radio on and was draining the battery. It had enough amperage to run the starter to start a normal engine, but not enough to get it reprimed and died on us. We are getting a jump pack to keep on the boat so that we aren't stranded again, but I want to fix the base problem so I don't have to keep it turning over for an extended time as well. What could the culprit be? Would it make sense to add a primer switch for the fuel pump to hit for a few seconds before starting the engine?

 

[Tim75]

You should have a "primer pump" already. Kind of a cube, left side of engine, with a fuel hose and 2 wires. Goes "thump thump thump" when you turn the key on.

Have you checked the delivery of the engine-driven pump?

 

[drxlcarfreak]

Are you talking about this cube? I thought this was the only fuel pump for the engine since it is a carb'd engine.

 

[Tim75]

Follow the hose. There should be another engine-driven pump tucked up close the the crankcase.

 

[drxlcarfreak]

It must be tucked behind the carbs, I didn't see it. Though, if it runs at full throttle, and it takes a ton of time to start it, you are saying that the square box is the pump I should replace?

 

[Tim75]

Fuel pump is aft of carbs, forward of looong throttle link. At least in my book for 2000 year carb engine. Follow the hoses.

 

[Sportster-2001-951C-Stock]

That metal box in your photo is an electric fuel pump. This is sometimes called a lift or assist pump, they are used to prime dry carburetor(s) and sometimes serve as the sole fuel pump. While running, this model pump goes: clap, clap, clap... The sound as the empty carbs fill and pressure builds will soften.

If that pump is running with switch on before cranking starter, this pump goes clap, clap, clap and your empty carbs should be filling with fuel independent of the pneumatic engine mounted fuel pump.

 

[drxlcarfreak]

I finally dug into the jet drive manual, ok I see that there are two pumps. So I am guessing that the electric fuel primer pump is what should run when I turn the key to the on position right? When I was diagnosing a separate ignition issue I popped off the hose after the primer pump to see if I was getting fuel flow, and I believe that it only ran when I was cranking the engine. I can double check this, but shouldn't it run continuously while the key is in the on position?

 

[Sportster-2001-951C-Stock]

See wiring diagram to determine when electric fuel pump is powered on (key on or cranking only) then proceed from there.

Normally, electric fuel pumps aren't running with just key on b/c in the case of a fuel leak the bilge could be filling with fuel if the key was left on.

 

[drxlcarfreak]

That would make sense. Seems like a dangerous situation.

I dug into the wiring diagram a bit. It didn't really help. The fuel primer pump +12v shows as on the same pin on the starter solenoid as the battery, so that would mean its always hot. The ground goes through a 4 pin relay, where pins 85 and 86 go to the electronic control module and engine harness plug. I am guessing that the ECM decides when to ground the pin out, and the harness is providing +5v, but I couldn't find anything in the manual describing the operation other than its there to provide fuel to the fuel pump while the engine is being cranked.

So based on that, I am guessing that the relay only clicks on while the starter is cranking. I can pull the outlet hose off to confirm this, but would it make sense to put a momentary switch at the dash to ground the relay out to run the pump for 5-10 seconds before starting the motor?

 

[Sportster-2001-951C-Stock]

provide fuel to the fuel pump while the engine is being cranked.

This is what I believe it should be. Perhaps you can confirm if the pump is running while cranking but this doesn't confirm it's moving fuel. To confirm it's moving fuel, you can pull the outlet hose and place it into a catch can using another piece of tubing.

If the carbs are dry, they're not getting fuel for some reason, electric fuel pump is suspect, also the check valve (anti siphon valve) at the fuel tank pickup tube. These valves are notorious for restricting fuel when they get some trash in them. Not all boats have them, most do.

 

[claycam]

Does anyone use an inline primer bulb to charge up fuel lines before starting? I’ve been using them on my 95 and 97 GTX’s for a couple of years and have noticed few, if any have mentioned or use them. It works like a champ for me.

 

[Tim75]

Check the filter that screws into lift pump.