HELP!!! engine will not accelerate

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reysafn

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Jun 20, 2012
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I have a 1984 3.8 v6 229. Runs fine at idle speed but when I push the throttle up it accelerates a tiny bit but give a little more gas it acts like it wants to accelerate but its just bogs out. It doesnt really lose power just wont gain any. I have cleaned the carb out put fuel stabilizer in the gas tank. I am getting fuel to the carb as well.

I was having a problem with water getting in the combustion chamber and took the heads in had them checked and shaved and new head gaskets. before I did the work on the heads I was having the same problem with the acceleration. I am loosing my mind trying to figure this out. Any help would be great so I can get this thing back on the water.
 
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dingdongs

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May 29, 2009
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649
Re: HELP!!! engine will not accelerate

dump fuel and get new.test with an outboard tank first to prove.renew all filters and restart process.once fuel is spent theres no magic cure to bring it back to life.
 
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reysafn

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Re: HELP!!! engine will not accelerate

even with bad fuel would it still start run fine at idle speed and start to accelerate but then start to cut out?
 
thumpar

thumpar

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Re: HELP!!! engine will not accelerate

How exactly did you clean the carb? Did you rebuild it?
 
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reysafn

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Re: HELP!!! engine will not accelerate

used sea foam and spayed it out. I could see fuel getting in the carb and it looks like its flowing fine
 
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reysafn

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Re: HELP!!! engine will not accelerate

so no I did not rebuild it. Strange thing is everything was fine when it came to the carb before it was torn apart the 1st time. Nothing was changed but now it runs like crap
 
NHGuy

NHGuy

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Re: HELP!!! engine will not accelerate

So the first problem was water in combustion chambers, which ones? Is that now solved? Did you get compression and leak down test info? Did you or your tech see a head warp or head gasket problem?
Mercruisers with water in the chambers aren't necessarily a head problem.
Check for the water & tell us if that issue is still solved.
 
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reysafn

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Re: HELP!!! engine will not accelerate

I put the heads on started it up ran it for a bit. Shut it down pulled the plugs and they were dry as a bone. When I took the heads in the tech said there was no doubt that they were warped. I was told water could get in through the exhaust but I ruled that out. Any thoughts?
 
Oshkosh1

Oshkosh1

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Re: HELP!!! engine will not accelerate

reysafn said:
so no I did not rebuild it. Strange thing is everything was fine when it came to the carb before it was torn apart the 1st time. Nothing was changed but now it runs like crap
Click to expand...

I don't get it..."no I did not rebuild it"...and "everything was fine when it came to the carb before it was torn apart"??:confused:

So you went to the trouble of tearing it apart...but didn't put a rebuild kit(new gaskets, pump, brass float etc...)in?

Sounds like you've got two different issues(assuming the water intrusion is not yet solved)...

An ACCELERATION problem(after it was "torn apart") sounds like a carb issue...

Tear it apart...again...clean it CORRECTLY, use compressed air to blow out all passages, jets etc...then replace all gaskets, accel pump and float. Make sure your power valve is not sticking either.
 
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dingdongs

Chief Petty Officer
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May 29, 2009
Messages
649
Re: HELP!!! engine will not accelerate

have you had a strobe light on the bottom pulley.if so rev the engine a little and see if your timing marks move.if not there are some counter balance weights under the plate in the distributer.they should move freely and fly outwards by centrifugal force.make sure they're not seized or rusted.we assume the timing is good ,the leads are on the correct plugs and try starting in up in the pitch black to make sure theres not a firework display of arcing going on.
 
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reysafn

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Re: HELP!!! engine will not accelerate

Sorry i was typing a little fast. Nothing was wrong with the carb before i tore apart the engine.
 
kylejb2663

kylejb2663

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Re: HELP!!! engine will not accelerate

I am almost going to guarantee you that it's a carb issue. My engine was doing the same thing, I would go half throttle and it would slowly start planning and when I hit full throttle it would just bog horribly. I had twins so one engine bogging limited the other engine from reaching max RPM as well- Replaced the carbs and they are good to go!
 
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reysafn

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Jun 20, 2012
Messages
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Re: HELP!!! engine will not accelerate

Well I rebuilt the carb and put it on and I still have the same problem. It gets to about 2200 rpm and bogs out. The one good thing is it starts up a whole lot better than befor. I just need to fix this bogging problem. Any suggestions?????
 
Oshkosh1

Oshkosh1

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Re: HELP!!! engine will not accelerate

Check your fuel filter(s) and pump.
 
Oshkosh1

Oshkosh1

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Re: HELP!!! engine will not accelerate

Tune up recently/Compression good?
Have you put a vacuum gauge on it?
 
skidooseadoo83

skidooseadoo83

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Apr 5, 2012
Messages
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Re: HELP!!! engine will not accelerate

Given all the fuel possibilities you have already looked at, it sounds like an ignition problem to me. Thats usually the best place to start with problems like this anyway. Points or electronic? If its points replace the points, set the dwell and timing. Then adjust your carb at idle if it needs it. If it still is doing it then start looking at your carb and fuel.
 
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