motor is missing

[razmous]

i have a 1996 mercury 115hp i brought it in for a tune up last year and its been missing terribly when over 2000 rpm and there is a noise (sounds like tapping valves)it gets up to speed then cuts out..i had a dealer check it out and they cant seem to find anything wrong with it...i wonder if anyone can suggest something...TY

 

[Laddies]

Re: motor is missing

Find another dealer that one apparentlly don't have a mechanic

 

[WillyBWright]

Re: motor is missing

Do a search on Mercury 115 and you'll see tons of info about the 1800-2400RPM range where they just can't decide whether to run on 2, 3, or 4 cylinders. There's nothing you or anybody can do about it. It's what they do. Just don't run there. For planing boats, that's where you just plow thru the water making huge waves and wasting a lot of gas anyhow. Most people don't do that. Plane it or idle it.<br /><br />The cutting out thing deserves a little more description, please. My current guess (and that's all it is) would be that the high speed windings in your stator have failed and you're losing spark above 3/4 throttle or so. Those stators crap-out on a regular basis. The replacement is red. Most have failed and been upgraded by now. A VERY hig mortality rate ... those early to mid 90s black stators. (It could also be the switchbox, they can do that too. Also a high mortality rate and the new ones are no better than the old ones.)<br /><br />Actually, a 1996 should already have the red stator. It's under the flywheel. You can see the plastic. If it's red, that ain't the prob.

 

[phatmanmike]

Re: motor is missing

actually there IS something you can do. try to find the top two carbs from another parts motor or donor motor. use them as replacements for your bottom two carbs. your crabs dont have idle circuits for fuel flow, thats how they cut off the "other" 2 cylinders<br /><br />once you have all four carbs the same, your engine will idle like normal. ive seen it done.<br /><br />2+2 is just a dumb idea

 

[razmous]

Re: motor is missing

For my merc,115 it idles good and no problem starting..today i changed a plug wire thought it could have been that but still the same,also pumped some gas into a glass to check for water..none...when im over the 2000 rpm range is where it gives me problems....it surges up and down and the most rpm i can get out of it is about 4200 to 4400 where it should get to 5200 if running properly,misses and goes all the time...wonder if its fuel or ignition problem or could a bad fuel filter give me that kind of trouble??? Thanks guys