Mercury 40 H.P. 4 stroke fuel problem?

[aidenscott]

I just bought a 1999 40 H.P. Mercury and it doesn't run to par. It idles well and if you slowly give it gas, it will get top speed. If you "goose" it from an idle, it will fall on its face and even stall. If you come off from top R.P.M. quickly, it will stall or miss. I changed the fuel and cleaned the carbs. There's a white needle valve on top of the three carbs called an "enricher". This piece has two wires running from it. Could this be the problem? If not, what could it be? It has spark and compression.<br /> Thank you,<br /> Rich

 

[buckshot944]

Re: Mercury 40 H.P. 4 stroke fuel problem?

i have the same problem on my 01 40 4 stroke, and have posted a few days ago with no response. sounds like a common problem.. <br />someone said something about the fuel pump,<br />i'm taking mine apart this weekend to see if its the problem. so far, new plugs, fresh gas, carbs cleaned, i'll post if i can fix it this wknd.

 

[aidenscott]

Re: Mercury 40 H.P. 4 stroke fuel problem?

if I hear of anything I'll be sure to pass it along

 

[aidenscott]

Re: Mercury 40 H.P. 4 stroke fuel problem?

anybody have any ideas?

 

[cistn]

Re: Mercury 40 H.P. 4 stroke fuel problem?

I recently bought a 30 hp 4 stroke, with my boat and have the exact problem to the letter.my engine will restart immediatley if i move the control to the start position, and then i am off again and running...this is driving me nuts. this is my first outboard on a 16' boat. i would hate to get stranded at sea with this...please pass any info on to me I would appreciate it...chuck<br />cistn@cox.net

 

[pat35]

Re: Mercury 40 H.P. 4 stroke fuel problem?

Originally posted by buckshot944:<br /> i have the same problem on my 01 40 4 stroke, and have posted a few days ago with no response. sounds like a common problem.. <br />someone said something about the fuel pump,<br />i'm taking mine apart this weekend to see if its the problem. so far, new plugs, fresh gas, carbs cleaned, i'll post if i can fix it this wknd.

 

[pat35]

Re: Mercury 40 H.P. 4 stroke fuel problem?

I was wondering how that fuel pump turned out, my 25 4 stroke died will only try to start when priming it, would love to know how it turns out pat

 

[cistn]

Re: Mercury 40 H.P. 4 stroke fuel problem?

DEALER TOLD ME THE PROBLEM IS IN THE STATOR, SAID IT'S A COMMON PROBLEM WITH OUTBOARDS....HOPE THIS HELPS, P.S. THEY ARE CHANGING MINE RIGHT NOW, SO I WILL REPORT BACK WITH THE RESULTS FROM THE WATER ON WED. NIGHT

 

[cistn]

Re: Mercury 40 H.P. 4 stroke fuel problem?

stator was replaced by dealer, boat and ebgine are running like new,, no stalls etc. i also can hit a top speed of almost 35 MPH now if i open her up as compared to 25 MPH before, very happy with speed and performance now...chuck

 

[thall511]

Re: Mercury 40 H.P. 4 stroke fuel problem?

I have a similar problem with around 2000 or 2001 40 hp 4-stroke motor has had carbs completely gone through fuel pump seems to have good pressure. idles good and is good at top end but cuts out in mid range. Changed spark plugs and has new gas going through it. When motor is cutting out seems as though top cylinder is the only one running but both the other two are sparking? Any Ideas??

 

[bleew0]

Re: Mercury 40 H.P. 4 stroke fuel problem?

I have been having same problem cutting out at mid range for a few years. Cleaned carbs a few times it was usable and if you pumped gas when it started to die and then hit the throtle fast it would get to top end. But now the problem is worse and the shop says it has conpression problems. I am about to try and figure that out. Need to get a manual.

 

[kmulya]

Re: Mercury 40 H.P. 4 stroke fuel problem?

My 40hp mercury had the same problem found a defective primer bulb, would run great then die . The start back and only idle. Clean carbs and found small pieces of rubber from the bulb in the pilot jetts clean and sync the carbs. Runs great at low speeds now. But higher rpms it will surge. My mercury gauges seems to be telling me that there is a problem with the middle cylinder. Probly more rubbler? It is amazoning how it is getting past the the inline filter. But how i'm can go fishing. Going to take it apart one more time and concentrate on the middle carb.