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I have a 2000 sea ray with a mercruiser alpha one. When i start it in the driveway it sounds and runs fine,but when its in the water and I get out of the no wake area a nd try to accelerate the engine bogs down and boat will not accelerate.I checked the gas to see if there was any water in it and it looked fine. I also replaced the spark plugs ,cleaned the spark arrestor,changed oil and oil filter.The prop also seems fine.I am stumped. Any suggestions?
1) Try starting it up at home in the driveway AT NIGHT. Look aroung the neck of the coil to see if it's cracked.
2) Take off the distributor cap and inspect. Does it look all corroded by the contacts?
3) With the distributor cap off, there is a little sensor that the rotor goes through. It will either have a little electronic pc board or be a chunk of black plastic - Which do you have?
4) Any chance you did a compression test when changing out the plugs?
My old Mercruiser did the same thing when I first bought it. I did all the usual... plugs, wires, rotor, condenser, cap, etc. I had the year old carb rebuilt and all was well.
I had a similar problem but only when it got hot (Mercruiser 5.7l 4bbl carb) Ended up being caused by sticky valve lifters and too thin oil that would not hold pressure and the hydraulic lifters would collapse (lose pressure) and cause a bogging accompanied by a valve tapping sound. My mechanic suggested a valve lifter chemical additive (designed for marine engines) and a switch to a higher viscosity oil and all is well again. Are you running the proper weight oil?
When was the last time you changed your fuel filter????? may have more than one also.. check them/replace them.. cary extra onboard.. especially with the new "ethanol" fuel
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I checked the fuel and it doesnt seem to have any water in it.I did find some particles floating in it. The fuel filter isn't clogged I checked the carb and seems fine but still having same problems.
Does it eventually come up on plane after bogging down? If a slow application of throttle gets you up to speed, then I agree w/ bill, accelerator pump. Easy to diagnose, sitting w/ the engine off and the spark arrestor removed,work the throttle by hand, the accelerator pump will spray a visible stream of gas into the throttle bores, if it's working correctly.
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OK, What engine is it? What year? 6cyl, 8cyl.?[img]../images/emoticons/confused.gif[/img] Do you know what type of carb it has? Really helps if you supply as much info as possible.
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What about the accelerator pump? Sorry Bill, after recalling one of your previous posts where your suggestion was spot on but ignored for two pages, I just couldn't resist.
2000 mercruiser 4cyl alpha one. The carb is a 2 barrel
Common problem with the engine. Mine (2000) bogs down from time to time, has done so for 600 hours. My buddies 07 does the exact same thing & I have read about the issue many times.
I just pull back on the throttle & feather it a bit. Then she will go. If you just put it down, she will bog & stall. Same deal on buddies boat...
This typically happens after she has sat for a week. After she gets cranked up, it won't happen again.
The accelerator pump shoots an extra shot of fuel whenever the throttle is moved/opened. They are somewhat adjustable for quantity AND duration of the fuel delivery. Often they deliver too little fuel, or the delivery is too short a period to work. It's also possible that the float level is too low or high, causing problems as the boat goes onto plane, and the angle is steep. Fuel may be uncovering the main jet pickup from the angle...or the accelerator pump. It's been a couple years since I did a 2 bbl. on those..I don't remember exactly the internal layout.
Stumble is almost always caused by a lean condition. I still think the accelerator pump calibration is the key. If it were a fuel flow problem it would occur constantly under load.
mercruiser engine bog 
