Was out on the lake today. When ready to go in for the day, boat started right up. I was running about 1800 rpm past several anchored boaters and the boat died as if it ran out of fuel. Tried restarting several times. It finally started, with the throttle in the open wide position. Even with the throttle wide open, it was only running about 2200 rpm. Decided to try to limp back to the marina that way.
I just replaced the fuel filter, primer bulb (with a quicksilver one), and fuel lines from the fuel tank all the way to the carbs this week. (they were 8 years old an the grey fuel lines were breaking down from ethanol). It ran fine Wednesday and Thursday evenings for about an hour each and worked fine this morning on the half-hour trip to where we were.
Does this sound like perhaps an air leak in one of the fuel line connections?
Nathan
Well, I think I may have found the problem... so I am going to post an outline of what I found, and what happened in the event that it may help someone.
It started because the boat was running rough at idle and hadn't been run for a couple of years.
I replace the primer bulb w/fuel lines because ethanol had eaten up the factor gray ones. (Thanks to whomever posted pictures of that online!)
Replaced the fuel filter, too, as it had pieces of the broken down fuel line in it.
Also drained the old fuel and put in new spark plugs plugs.
The boat ran GREAT for about 2 hours, then acted up with the symptoms that started this thread.
So, I checked spark, etc, to make sure it wasn't an ignition problem. Everything looked good.
Ran off an auxillary tank to rule out vent and anti-siphon valve. No change.
Checked all the fuel lines for leaks. No change.
So, I figured if the fuel lines had broken down and filled the fuel filter, there was probably junk in the fuel pump, so I rebuilt that. And i was right, it was junked up pretty well. Unfortunately, no change.
Worse yet, I pumped up the primer bulb to check for leaks and blew the small hose that where the oil is added to the fuel line right before the fuel pump.
Since everything pointed to a fuel issue, I decided it must be in the carbs. I now had time to kill since I blew the hose right before the fuel line, so decided today was the day to pull the carbs and check them.
When I pulled the attenuator plate, it exposed the 1 to 2 inches of fuel line I couldn't see before.
That section of fuel line (which incidently is the hose that I blew when pumping the primer bulb...) had a 180 degree twist in it!
Here's what I think happened:
The marine fuel line I purchased to replace the primer (the tank and engine connections are clamped on, not quick connect), is extremely thick. It has a rather large OD. So, I had to work really hard to get the fuel line onto the hose barb at the engine. I think I probably ended up slightly twisting the fuel line at that time.
Then, on the day everything went south, I picked up the primer bulb and twisted it to point the arrow up for priming, and probably twisted the line badly just under the cowling,
I have to wait for the replacement part (it's not a regular fuel line, it has two molded in connections coming off it for the oil line and fuel enrichment circuit), so I pulled the carbs anyway. They were very, very clean.
I am really, really surprised at how flimsy this short piece of fuel line is (after all, it blew out from priming the bulb, though I suppose ethanol could have broken it down).
But, bottom line, there was a huge twist in the fuel line in the one blind spot where the fuel line couldn't be visibly check for integrity.
Once I get the replacement in, I'll post back to confirm if that was the problem, but I'm pretty convinced.
