Mercury 115 help

[DAVID146]

I HAVE A 1998 115 2+2 2 STROKE. Change the water sep filter to a 10 micron. took it out today and take off was slow would not build past 4500 rpm under load and ran only 25 mph used to get 30 to 35. check the plugs top three have oil and gas on them 4th is clean too clean. there is also no idle change when i pull the wire off that plug but is seams to have spark/under idle I can bog it down with wd 40 when i spray it in that carb same with the other three carbs any help? IT looks like it has been running lean for a while could my main be cload I know it is getting some fuel.

 

[pinellas50]

Re: Mercury 115 help

This problem surfaced after you replaced the fuel/water seperator filter?

 

[Maxz695]

Re: Mercury 115 help

do a compression check on #4 you say it,s clean too clean no gas or oil correct? Does it get good spark at 7/16ths away from a groung. It could be a coil. That depends on your compression check get back to us

 

[DAVID146]

Re: Mercury 115 help

CARBS CLEAN, NEW FILTERS, PLUGS, COMP 120 ALL FOUR, ALL HOSES GOOD, SWITCH COILS. but still when you turn it over with the wires off the 4th cyl still has little fuel on it the other plugs are full, also their still is no change when i pull the 4th wire off when running. what would keep the fuel from the piston?

 

[DAVID146]

Re: Mercury 115 help

Also what should the mpg be?

 

[Maxz695]

Re: Mercury 115 help

there seems to be a spark problem related to just the one cylinder. I would almost rule out the switchbox at this point. I would not rule out the coil wire from the switchbox though and any wire leading to the coil itself. It may well be the coil itself try switching another coil with that one and see if it works then. if it does get a new coil

 

[Big flop]

Re: Mercury 115 help

does the fuel pump have a pulse hose going to that cyl?
bad diaphragm?

 

[Faztbullet]

Re: Mercury 115 help

You wont see much of a change as this set-up has no idle mixture and fuel is restricted to #3 and #4 cylinders. #3 cylinder should also do the same as #4 when tested, if you have fuel on #3 at idle the carb is flooding. This motor only runs on the top two cylinders and then kicks in about 1500-1800 rpm to run on the lower cylinder, thats why it call a 2+2 motor. If the plug is steam cleaned along with top of piston you have water intrusion into cylinder due to: lower crankshaft seal bad, exhaust plate leaking or broken/chipped reed problem..

 

[DAVID146]

Re: Mercury 115 help

its water faztbullet check yout pm