need a little input

1agofst

i have 3.0 merc i/o

there is black smoke coming out of my exhaust and a black crud

we had it out for the first time this year and everything was fine and then the second trip was a no go,it was idling rough and blowing black stuff out of the exhaust,i cleaned the carb since the butterfly was not opening,it is now opening but still have rough idle and black smoke

could it just be bad gas or is it a carb problem

thanks

mvn

I had this issue with a Holly 4-bbl carb once.  Had it rebuilt and everything was fine after that. 

 

Check the flame arrestor for cleanliness, check any vacuum lines for cracks, replace the fuel filter/water separator, make sure your gas is fresh........the obvious stuff first.  Someone else will probably have more/better advice.

 

Mark

Babyboomer

What drive do you have Alpha or Bravo I've seen Bravo 3 when the impeller goes out blow some smoke and burnt rubber. Was it running hot? 

mvn

OP has a 3.0L Merc.....Alpha One.  Good point though Boomer....what was the temp?

Mark

Babyboomer

What I thought on Alpha so I don't have a clue |)

1agofst

temp is fine

once i hold the carb open with a screwdriver it purs like a kitten,but when i take the scredriver out, the butterfly closes and it starts smokin and idling rough,i spprayed it with carb cleaner and it opens now,but it's still smokin and idling a little rough,i just wanted to check here before i take it to the shop and have to spend any money

i have a puddle of black water in my driveway from the exhaust,it looks like carbon

oh btw it's on a 94 rinker 180 lol,i forgot to put that in the post originally

bat32

Is the choke working?

212rowboat

Take your positive crankcase ventilation valve out and shake it.. if it rattles, it's most likely okay.. if it doesn't, it's likely stuck... If it's stuck open, you've got a nice drinking straw for your intake to sip oil right out of the valve covers.. if its stuck closed, you could have too much pressure creating and/or facilitating blow by of gasses past the piston rings... Neither is any good.. it's like a ten dollar part that can be a monster if left unchecked.

Oil burns bluish to blackish.. super fuel rich does too, but more brackish than oil..

Pull a spark plug.. snap a pic of the business end.. post it.. let's get a look at what's happening in that thing!!

mvn

Choke?   I totally forgot about that one!  See what happens when you stop playing with carbs??!? 

Mark

1agofst

thanks guys

turns out it was the choke stuck,and some bad gas

i appreciate all of the info,yall just saved me an expensive trip to the shop

1agofst

well fellas it seems that one of the needles in my carb was bad,the rubber tip on the end was half missing

so we did a carb rebuild and hit the water,she ran great for a while and when i came out of the dreaded no wake zone,i nailed it and it bogged out and shut off,luckily it started back up,i had to feather the throttle to get it goin full throttle again,so who knows,but i did notice my voltage guage was reading 18 and the battery was hot as could be,got it home and checked the water level in the batt and it was low,so hopefully that is the culprit as of now lol,i will find out this weekend haha

enjoy the water my friends

mvn

Yikes.....18 volts??!?  Can you take a voltage reading with a handheld volt meter?  The helm gauges aren't the most accurate.  If you still see that high of a voltage, I would suspect your voltage regulator/alternator.  That would explain your hot battery.

Mark

1agofst

im gonna check it with a volt meter when i get home,i hope i didnt toast the battery cause its only a year old

i"ll let ya know the out come,thanks for the input mvn

1agofst

mvn,i like your avatar,bob denvers wife is a good friend of mine

212rowboat

Ethanol is hades on carbs.. all you can do is treat it or find rec fuel. It'll eat rubber quick like.

raybo3

If you have been pumping 18 volts you should be happy if its only a battery that is bad. You really need to find out if you have a voltage problem before you have more MAJOR problems....

1agofst

checked it with a volt meter,it was reading 14.42,good thing,guage must be bad,carb has been rebuilt,but boat shop didnt  check electric choke when they rebuilt the carb,according to the mechanic,the choke aint closing,so  i'm just waiting on him to fix it,so we can get back on the water