3.0 bogging during acceleration

iron21

Petty Officer 3rd Class
Joined
Aug 31, 2004
Messages
97
well, today i just finished paying off my boat slip and went out for a cruise. i have an'89 mercruiser that has ran good for the past 2 months. All off a sudden, 10 minutes into cruising today the engine starting bogging and stalling constantly. Mostly while accelerating, and if i didnt back down the throttle it would die out, however it would start back up.The oil seems fine, so i'm doubting its the head gasket. It also has fresh gas.Not overheating. What else should i look into ? This is really frustrating and hope to have it solved asap. I would appreciate any suggestions. <br />-Jamie
 

waterone1@aol.com

Lieutenant Junior Grade
Joined
Oct 10, 2004
Messages
1,235
Re: 3.0 bogging during acceleration

To start with the easy stuff : You said that it had fresh gas.....when was the gas/water seperator changed last ? Have you changed or inspected the gas filter at the carb inlet lately ? Have you tried running it with the gas gap off or loose, to insure that the vent line to the gas tank is not clogged ? Have you checked all gas line connections and hose clamps to make sure that it is not "sucking air" ? Finally, has it had a tune up including plugs, dist.cap and rotor lately ?
 

jeff13601

Chief Petty Officer
Joined
Apr 30, 2005
Messages
593
Re: 3.0 bogging during acceleration

While checking things check the clear line from the carb to the pump for gas. If there is the pump is going. Also check the pump for proper flow
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: 3.0 bogging during acceleration

Check your water separator.........
 

iron21

Petty Officer 3rd Class
Joined
Aug 31, 2004
Messages
97
Re: 3.0 bogging during acceleration

ok, to update my bogging problem... i recently put fresh gas in and my boat ran fine for about a week. today i took it out again in rough water. ran great at first, but at about 3/4 throttle the engine would bogg and want to stall ONLY when i bounced the boat around large waves and wakes of other boats. So it seems the engine runs fine in calm water, but in rough water it has wants to bogg or stall. also, i was wrong when i said "Acceleration bogg" because i realized it does it when cruising too..anyways, what do you think might be causing this? it almost seems like it is starviing for fuel, but why would it run fine in in calm water??...thanks, i appreciate the help..<br /> Jamie
 

THE BEEF

Chief Petty Officer
Joined
Jun 11, 2005
Messages
432
Re: 3.0 bogging during acceleration

Is it carburated or fuel injected? When it boggs down can you see black smoke or smell raw fuel? <br />If the carb is original and has not been apart<br />chances are you have a black plastic fioat in the carb. These pain in the butts cause all sorts of problems.mainly flooding,fuel just dumps down the carb causing big problems.If you change the float make sure its a brass replacment.The old one will look fine and feel very light but in fuel they saturate and cause fooding and bogging down.<br />Big problem in 1970'cars. Ask your auto mech.<br />Good Luck
 

iron21

Petty Officer 3rd Class
Joined
Aug 31, 2004
Messages
97
Re: 3.0 bogging during acceleration

it's an '89, so yea it has a carb. yes, very rarely, i will see black smoke.i will take a look at the float. Thanks for the info
 

Richard Petersen

Senior Chief Petty Officer
Joined
Dec 17, 2004
Messages
778
Re: 3.0 bogging during acceleration

Look for water in the float bowel. You have and change the water seperator?
 

iron21

Petty Officer 3rd Class
Joined
Aug 31, 2004
Messages
97
Re: 3.0 bogging during acceleration

no, actually my boat doesnt have a water/fuel seperator.. i wonder why they dont put them on all boats
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: 3.0 bogging during acceleration

You can buy after market water separators, cheap and easy to install. Have you performed any of the diagnostic checks that waterone 1 & jeff 13601 described? I think you have water in your fuel that sits at the bottom of your tank while cruising nice, and gets shaken & mixed when you hit rough water. Try siphoning [very carefully]out the bottom of your gas tank into something clear and see what you've got.
 

Mahoney

Chief Petty Officer
Joined
Aug 2, 2004
Messages
537
Re: 3.0 bogging during acceleration

I like what Don suggested in another post, and found it would have been helpful for me. I was able to run the engine fine on the muffs with no hesitation after the boat was sitting a while. The pickup tube doesnt quite reach the bottom of the tank where the water settles. If you can let the boat sit at an angle so all the water sits at the bottom of the sending unit hole, you can try and use a semi-rigid hose to siphon the stuff on the bottom and see what comes out.
 
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