1995 Crownline BR202 with a 305 V8 engine.
Background: Only got to use the boat once in summer 2019 so when getting it ready for this summer, was expecting some issues with fuel from 2018 still in the tank., I had added stabilizer but we are still talking almost 2 years.
It started up in the driveway but experienced pretty bad surging. With about 1/4 to 1/2 throttle, it would surge up to around 3000 RPM and then fall down to around 1000 before surging back up. It would do this as long as you let it run.
So I took my medicine and siphoned all the old gas out (or at least as best as I could tell). Rebuilt the carburetor and replaced the water separating fuel filter. After that, it runs great in the driveway on the muffs.
Went to the lake two times and it runs great for an hour to about 90 minutes and then starts to bog down. You'll be cruising along at 15 or 20 knots and then out of the blue, it will start to hesitate and surge again as it tries to stay running and occasionally you hear a puff of air coming from the engine. If you lower the RPMs to under 2000, it will stay running longer so you can limp your way back to the boat ramp, but still eventually dies. But it will start right back up immediately although if you give it a couple of minutes before you try to start it again, it seems to last longer before it dies the next time.
So I figured there still has to be water/old fuel at the bottom of the tank and pumped another 6 or 8 gallons off the bottom of the tank (assuming that the bad stuff would all settle to the bottom of the tank). I replaced the water separating filter again and also replaced the fuel pump and went yesterday and the same thing happened. Ran beautifully for about 90 minutes and then boom, bogged down.
I am out of ideas...I feel like I've replaced every component of the fuel delivery system except for replacing the tank itself. I didn't mention above, but I've added plenty of Seafoam to the tank too. I've pulled the small inline filter right at the front of the carburetor a few times too and it will occasionally have a small amount of varnish on it but not nearly enough to create an obstruction.
I would say to siphon all the gas out again, but the fuel in the tank has to be 95% fresh so I think it has to be varnish/sludge or something in the tank getting sucked up and causing a blockage that interrupts the fuel flow. But I don't understand why it always happens right about the same time...typically between 60 and 90 minutes of being out on the lake. And I can't duplicate it in the driveway...I've let it run for an hour or so in the driveway and it runs fine but obviously, it isn't under the kind of load it is under while on the water so I'm guessing that has something to do with it.
Any ideas though would be appreciated...thanks!
Background: Only got to use the boat once in summer 2019 so when getting it ready for this summer, was expecting some issues with fuel from 2018 still in the tank., I had added stabilizer but we are still talking almost 2 years.
It started up in the driveway but experienced pretty bad surging. With about 1/4 to 1/2 throttle, it would surge up to around 3000 RPM and then fall down to around 1000 before surging back up. It would do this as long as you let it run.
So I took my medicine and siphoned all the old gas out (or at least as best as I could tell). Rebuilt the carburetor and replaced the water separating fuel filter. After that, it runs great in the driveway on the muffs.
Went to the lake two times and it runs great for an hour to about 90 minutes and then starts to bog down. You'll be cruising along at 15 or 20 knots and then out of the blue, it will start to hesitate and surge again as it tries to stay running and occasionally you hear a puff of air coming from the engine. If you lower the RPMs to under 2000, it will stay running longer so you can limp your way back to the boat ramp, but still eventually dies. But it will start right back up immediately although if you give it a couple of minutes before you try to start it again, it seems to last longer before it dies the next time.
So I figured there still has to be water/old fuel at the bottom of the tank and pumped another 6 or 8 gallons off the bottom of the tank (assuming that the bad stuff would all settle to the bottom of the tank). I replaced the water separating filter again and also replaced the fuel pump and went yesterday and the same thing happened. Ran beautifully for about 90 minutes and then boom, bogged down.
I am out of ideas...I feel like I've replaced every component of the fuel delivery system except for replacing the tank itself. I didn't mention above, but I've added plenty of Seafoam to the tank too. I've pulled the small inline filter right at the front of the carburetor a few times too and it will occasionally have a small amount of varnish on it but not nearly enough to create an obstruction.
I would say to siphon all the gas out again, but the fuel in the tank has to be 95% fresh so I think it has to be varnish/sludge or something in the tank getting sucked up and causing a blockage that interrupts the fuel flow. But I don't understand why it always happens right about the same time...typically between 60 and 90 minutes of being out on the lake. And I can't duplicate it in the driveway...I've let it run for an hour or so in the driveway and it runs fine but obviously, it isn't under the kind of load it is under while on the water so I'm guessing that has something to do with it.
Any ideas though would be appreciated...thanks!
