TOPIC: 77 115 plug color

I got a question on plug color for a 77 115. Mine seems to drink the fuel and the plugs are always wet lately too rich? It seems to run ok. solid 35mph pushing a 16ft mfg with five people 25 gallon of fuel and cooler plus the dog. It has a 15 pitch 3 blade. I think it is to rich any help would be great.

surface gap plugs are always black.

You might try tweakin' the idle mix screws in just a little, but if it's running well, I wouldn't go much if any. It's much better to run rich than lean, IMHO. It's not fouling plugs, right?

sounds like cold fouling. Turn them in just enough till they begin to lean then bring them back out a bit. I have a 73 1150 head on a mid eighties mid section. She does like to drink the fuel. I am going to go through the timing steps again to be sure I am on and re adjust the carbs again but being that it is pushing 1900 lbs of lapstrake it just may be the nature of the beast. That motor pushed me around at 2500 RPM (21 to 22 mph) according to the GPS without breaking a sweat

What everyone has said plus I would look at a few more things.
First I would not suspect wet plugs unless you do a LOT of idling and then pull the plugs to look. The plugs will look dark but dry when motor is run at higher rpms then plugs pulled. The polar gap plugs do run cool so are dark colored when everything is "normal".
Idle mixture is not so important at higher throttle settings BUT your float level is. High float level means rich running. Also, are you sure someone did not swap on 1400 or 1500 carbs? They fit and are jetted much richer in the high speed circuit. Someone may have thought they were hot rodding the motor doing this swap........it doesn't work that way.
Carbon tracking in the distributor cap will cause miss fire that you may not notice. A faulty coil can also cause weak spark or misfire. The wiring on these motors is notoriously bad with with age, you may have a frayed wire on one of the many switch box or distributor trigger wires which would also cause misfire or weak spark. All these issues could lead to unburned fuel on the plugs.
Your speed sounds a touch slow to me for a 1150 but maybe not, that's why I am suspecting some misfiring which is masked at higher RPMs this would lead to wet plugs and poor economy. I have had several distributor 1150's over the years and they are fairly economical. But older big two cycle carbed outboards in general are not good on gas.
My 2 cents,
Randy

here is where I am at new plugs and cleaned floats and reset the float on the carbs. The plugs are now dry almost still new very little deposit of black still look all most new, no signs of per ignition or to lean in my opinion but I can hear what sounds like pinging( what it sounds like in a four stroke hot rod motor 350 in a car) what is suggested now to look at now

67sears wrote:

here is where I am at new plugs and cleaned floats and reset the float on the carbs. The plugs are now dry almost still new very little deposit of black still look all most new, no signs of per ignition or to lean in my opinion but I can hear what sounds like pinging( what it sounds like in a four stroke hot rod motor 350 in a car) what is suggested now to look at now

Have you checked the timing?

The plugs on my 1350 have always been more black than anything else...but ive found that true of most things "2 stroke"...especially if you run them down low a bit. Judging by your boat\load\motor\prop setup, id say your probably about right where you should be give or take a couple MPH. The whole fuel consumption thing could be how hard you are running it. Mine drinks fuel like a drunken sailor if i blast around all day at WOT. But back it off to 1/2-3/4 and its actually quite conservative.

If it doesnt stall out and doesnt seem to have any operating quirks, id probably just leave it alone as long as it seems like its running ok. Thats sort of my motto though...seems the more i wrench on them, the worse they get!

But if your hearing "pinging", i would double check your timing...and make sure your running a quality, high octane fuel.

I run 93. funny the trip i got it took it out with three people and not even a life jacket it ran 37. Now water pump fuel pump and plugs 32 full boat so it's prob ok but i hate to hear ping so I will tinker a bit but thanks for all the help. I am thinking a tach and maybe a 17 prop to help the fuel usage.

and I am gonna check timing and reduce 2 degree