HELP HELP HELP mercury 1988 115 inline 6

[stephenhudack]

Hey guys i just bought a sea ray with a 115hp merc on it. It has 3 carbs six cylinders. The power head was redone 20 hrs ago compression is great in all three cylinders. I started up boat in my drive way several times and ran through the motionbs several times. The boat would run up to 5500 rpms in gear and in neutral aqnd sound great. SOlast weekend i took it out and found that i couldnt get the boat over 2000 rpms. But still would run tp 5500 in neutral. The boat seems to break up and miss it sounds like after 2000 rpms. I changed all 6 plugs not the problem. I tested all the coils by removing coils from the plugs one at a time listening to the motor, all six cylinders are firing. DOES ANYONE HAVE ANY SUGGESTIONS ON WHAT TO DO NEXT!

 

[Ware5150]

Re: HELP HELP HELP mercury 1988 115 inline 6

I have a 1985 115 inline that wont idle. I have tried everything so I might be able to give you some help. To me it sounds like you have trash in your fuel tank. Pull out the screen on the fuel pump, clean and inspect. Add a clear fuel filter to the line. (Walmart) This way you can see if you are getting clean and constant fuel.

Let me know
Later

 

[jimg984]

Re: HELP HELP HELP mercury 1988 115 inline 6

shouldn't never go over 2000 rpm in netural or in gear out of the lake probably broke a valve inside the engine good luck and learn from this

 

[tigerlegend2000]

Re: HELP HELP HELP mercury 1988 115 inline 6

correct me if i'm wrong.... there's no valve in merc, inline 6 .... 2 cycle-->no valve.... are you talking about reed block?

 

[cannonford57]

Re: HELP HELP HELP mercury 1988 115 inline 6

at 5500 rpm in neutral,take your pick,reed,reed block,rod,piston,any combination of any or all of them,something will bee outside of the engine soon.always keep it under 2000 tops in neutral....just my opinion of course

 

[verado7]

Re: HELP HELP HELP mercury 1988 115 inline 6

your lucky you didn't lose the motor already - it's called run-away and will destroy your engine. 2000 max like evryone else said - however you might have a bad fuel pump ( she's a hungry one) - or the carbs need rebuilding and should be done every few years as a routine - theres nothing to lose by doing those things especially if you dont know when they were last done . if that doesnt clear it up then we can talk electrical - which gets expensive so you need to know how to use a voltmeter or even better a dva meter which runs 200 bucks on average in canada - the latter you can pick up for 20 and a manual to get the numbers from - but likely someone else will post them here for you -but haveing the manual is always a good thing

 

[stephenhudack]

Re: HELP HELP HELP mercury 1988 115 inline 6

thanks for the info guys. I found the problem its definately the fuel. I took off the bowl on the fuel pump and found it dirty with black rubber . I cleaned everything off and took it back out and it ran great for about 15 minutes. So im thinking the fuel lines are breaking apart so im going to buy new ones and install them. I also put a inline fuel filter in but i think that may be resticting me as well. Time for some more troubleshooting