*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Change the fuel filter. You said it wasn't clogged but how do you know. Also like i said before make sure you dont have 2 filters. CHANGE both no just check them. If you boat ran fine before(in the past) the adjustment on the accelerator pump isn't gonna change enought to make that problem you are describing. only in an instant where you slam the throttle down will the accelerator pump make a difference. She is starving for fuel, check the most simple things first!
Also just because there is fuel getting through the filter doesn't mean there is Enough fuel getting through that the engine is requiring while under a load.
__________________ B.O.A.T - Break out another thousand
I'll try replacing the fuel filter anyway and see if that is the problem.We havee been going out almost every weekend so I don't think the furl could be bad. I was able get up to plane very quickly without problems until recently.Now I can;t even get up to plane no matter what I do.
If it's readily accessible, also remove the fuel pickup from the tank and check the inlet. There should be ascreen on it and there have been more than a few occurrences lately where the screen has been partially clogged, cutting off the fuel flow. It's easy to spot on an outboard because the primer bulb collapses.
__________________ Any Port in a Storm!....currently seeking shelter.
You may also want to consider using a portable tank connected directly to the fuel pump for a quick diagnostic run. Have you switched to ethanol fuel recently?[img]../images/emoticons/confused.gif[/img]
__________________ Any Port in a Storm!....currently seeking shelter.
Remember in your assessment of fuel flow that the float bowl holds several ounces of fuel. If you turn the fuel off completely, most engines will run for a minute or so on the residual fuel in the bowl. Check the fuel pressure at the inlet to the carb to ascertain proper fuel flow.
The ethanol fuel issue is a very valid consideration. It (ethanol) contributes to fuel contamination, and vaporizes differently in the carb. Ethanol is an oxydizer, meaning it contributes additional oxygen, causing a slightly leaner mixture. this is irrelevant in a fuel injected engine with O2 sensors, but can cause carbureted engines to run lean. Back to the accelerator pump to fatten the mixture at throttle change.
Just checked the carb the accerator pump squirts jets into the 2 barrels and the choke is completely wide open. It will only close if you manually close it.The coil that is connected to the choke gets extremely hot.
Choke coil is supposed to get hot. It's a bimetallic element that winds/unwinds with heat. Choke only closes when cold. The question is..how much and how long does the accelerator pump squirt? does it still squirt at part throttle? Of course you can't check this at the dock unless the engine is not running. There's still the possibility of float level..the carb should transition from idle circuit to main metering circuit around 1500 rpms. A low float level will delay the transition, causing stumble.
Have you changed the fuel filters? With the recent addition of E10 to your tank that could easily send any junk in your tank into the filter. You did say you see junk in the fuel. Also how about a tune up and checkig the timing?
I changed the fuel filter today.I also installed a fuel/water seperator.I added some stuff that takes the ethanol out of the gas. I took the boat out to test it and no change. It keeps stalling out and when I try to throttle up engine bogs down and stalls.The accelerator pump still squirts at part throttle.
i changed the pump filter, added a water/fuel seperator- added ethanol additive, fuel enzyme cleaner. the choke does not open or close except manually by hand- hard to start except pump gas a few times, and advace throttle a little bit..... it still dies, and bogs down when in the water
The choke should be closed only when the engine is stone cold. Timing retarded? I still strongly suspect a carburetor problem..float level, plugged main jets, weak accelerator pump. Is there a filter in the inlet of the carb that is blocking fuel flow?
My Holley 4bbl's are stumbling a little now with ethanol laced fuel. I'm jetted pretty lean, so it is more obvious. Are you in florida?
Re: mercruiser engine bog 
