Rethink that it's really 14.7:1 As seen here..https://www.google.com/search?ie=UTF-8&client=ms-android-att-us&source=android-browser&q=air+fuel+ratio
If it's not a fuel issue, try moving all the wires around and see if you can make it happen, could be a loose connection??It also sounds like it could be a coil breaking down??
the 2+2 engine is a simple but at the same time complex engine... the actual "kick in" of these is caused by fuel being metered by the second progression hole in the lower 2 carburetors.. controlled by the carburetor linkage.. this is why set up is so crucial on these motors... an accelerator pump with the aid of 2 check valves helps that resemble needle and seats more than check valves, Controls acceleration. during idle.. only the top 2 carburetors have air/fuel mixture screws... the lower 2 receive a token amount of fuel but lacking air cannot fire , this lubricates the lower cylinders and the fuel is scavenged and burned by the upper 2 cylinders via a complex network of check valves and bleed hoses ... once the throttle plates are opened the accelerator pump takes over for the temporary lean condition and the carburators then meter fuel via the main jet like a normal carb....Now for your problem...most likely you have a bad coil... it's very common on those engines... a stator or trigger is also a strong possibility but I'd place money on the coil.
Do you know anything about props?
At the mouth of the river at Sebago in the Spring, it's East to West unless you want a beating from the rest!
Don’t hit a rock with them.
Only done that once, talking on the phone while leaving the basin and kept the red markers on my right, whoops!
.. yes..more than the average boat owner..and then some...I may have a set of coils and a switch box for that 91 merc... I had a 95-115 2+2 that lost a fly wheel and ate the stator and trigger...it was cheaper to buy a used engine than buy a flywheel and ignition system because the flywheel was obsolete and it would require the entire ignition system to be changed.. I stripped the carbs and electrical system off of the motor thinking it was going to fit my 2004 115- 2+2( spare parts not knowing they would not work)... but they changed the electrical system a bit by eliminating the switch box and went to straight CD cols power packs...I'll look and see if I still have the coils and switch box...I also may have a 17 and 19P aluminum prop...I've given some stuff away ( helped a few others in your predicament)..not sure whats left from that motor.. what I do have can be had for the cost of shipping or you can come and get it for free.
I'll shoot you a pm about my prop question if you don't mind??
No more talking on the phone while driving a vehicle or boat here in RI.
1st - you were speaking about gas to fuel ratio, or Stoichiometry. Stoichiometry for a naturally aspirated combustion engine is 10:1. Not 14:12nd - it's been a long time since I've seen a diesel outboard3rd, and lastly, I said that a 14:1 air/fuel ratio would be running excess air, or lean. A lean burn produces a hotter flame and CAN burn up pistons. Further, that is, unless things have been designed to handle a lean fuel ratio you don't want mess with what the motor was designed for unless you know what you are doing. Things like running higher octane fuel to slow down the burn rate and/or using higher compression ratios, and advancing/retarding the ignition timing to avoid detonation are all options when playing with air/fuel ratios. But you had better know what you are doing.But, again, you were attempting to speak about Stoichiometry in your original post Boon and I simply corrected and/or clarified what you posted.