Mercury outbard 35hp running like c**p HELP!!!!?

Question

I have a 1984 mercury 35hp outboard that runs like c**p. when i ltry to throttle up the engine it falls on its face. if I throttle up really slow and I mean slow I can get like 3/4 throttle out of the controls but i am still going really slow. it is like the enginge isn't getting enough fuel. I pulled the carb and cleaned it out and it now runs even worse thean it did before. and it won't stay idling on its own. I have to have the throttle at half and if I go below that the engine dies. I have to rev up the motor and then throw it into gear to get it to run.

is this a fuel and carb problem or is it something else. if anyone can help that would be great.

Thanks

Answer 1

First, you need to do some basic diagnostics.  Pull the spark plugs, check their condition.  Do a compression test to eliminate internal failure.  Look for water in the fuel.  Check for good fuel pressure from the pump.  Having eliminated all of the above, get a service manual and start testing ignition components.  This is hard to diagnose without hearing the motor.

Answer 2

Yes it does sound like you have a fuel problem,but first are you sure it has spark to both cylinders?The next thing to check is your primer bulb.When you were trying to get it going

faster ,did the primer bulb stay hard?I suggest that you install

a new diaphragm in the fuel pump.They are not expensive,

about 7 dollars.After you rebuild the fuel pump and start it up

you will need to reset your idle s***w because it will not be correct from when you cleaned the carb.Lightly s***w it in until

it is tight,then turn it out 1 1/4 turns.Once you have started the engine and it has warmed up,turn the s***w in slowly until the motor starts to sputter.Then back it out until it runs smoothly.

Once you have it there turn it out about 1/4 turn farther and it

should idle perfectly.If this does not fix your problem,write again with more info.Good luck.

Answer 3

Sounds like the last merc my old man owned. Had to split the block and replace the bladder/diaphragm.

Answer 4

I see the brain trust of good mechanics have already answered your question.  JTexas, Mrfixit and Jims are as usual right on target.  

       As this is an older engine, I wonder if it's been sitting unused for a while.  If so, Do a compression check.  If on the low side, really look at the powerhead closely.  OMC and others used to have a "tune-up in a can", You might want to give it a try.  It frees stuck rings.

Answer 5

sounds like carbs  its running worst since you messed with them  that should tell you something  maybe the needls need replacing  bring it to a shop

Answer 6

Stop throwing it into gear at high RPM's, unless you're ready to spend a couple thousand rebuilding your gearcase.

if carb needle adjustment as described above don't do it, check the linkage between the throttle and spark timing advance -- the spark advance has to begin *before* the throttle butterfly starts to open.