78 johnson outbouard,heavy smoking when idling,won't plain out,has muffled sound when throtled up,?

Question

Motor has been well maintained,have noticed a drain in the battery if left sitting for a while. Lately, have had to jump start,have changed plugs,but still didn't work,will start and run in idle mode. When in open water,when trying to plain out,just goes into a muffled suond and speeds up a little,but not what it should be doing. Any advice is helpful.

85 HP,V-twin,it has 4 spark plugs,I think maybe, I might have put alittle too much oil in the mix, could this be gumming up the carb? How do I correct?

I put the required amount of oil for 10 gal. of gas,dumped it in the tank on boat, then drove 7 mi. to gas station. Could only get 8.87 gal. in tank, drove to lake, another 8 miles down the road,put in water,startes and idles fine, when leaving channel going to open water, I heard the sound of the motor change to a muffled sound,tryed to get it to plane out, but could not. Would go alittle bit,but still had this muffled sound to it. Will start and idle,and go at a no wake speed just fine, but will not plane out when throttled up. Just recently I have noticed, I might have a bad battery,or bad cell in battery, would this cause my spark not to be hot enough?

Answer 1

sometimes on boats (older ones especially) the manufacturers were bad about the overflow hoses and there routing. since you mention nothing about the engine having problems before(filling with gas) I will assume the problem started after. when you stuff or force fill a boat and gas comes out of or fills the overflow line it does not always drain back into the tank(s-curve or bend in hose). this causes a vaccum in the tank very quickly when you run the engine fast or idle for a while. I would hook up a remote tank with correct fuel/oil mix and try before you do anything to motor. then you will know where the problem is- motor or fuel system. (ps that motor will idle fine on two or three cyls but not have any power) also that engine has a minimum cranking speed if the engine starts and will run the battery will not effect spark(magneto ignition)

Answer 2

There are a few things you can do. One, disconnect all electrical devices except the motor and recharge the battery. Wait for a time ( maybe a day) and see if the discharge problem is still there. If it is, then check the electric choke solenoid, and the helm switch either of them may be sticking. If that is not the problem check the float switch for the pump. You can even connect one item at a time in the dark and see if there is a very small spark. The one that sparks is drawing a load and it maybe the one causing the problem. Or, replace the battery. It may be old or defective. As for the running issue, check the carb adjustments (idle and high speed settings)
check the timing marks (remember, when aligned, wait for the throttle plate to move not the linkage) empty the fuel container and change it. check that the carb is tight at all points and not sucking air. The slightest looseness will cause problems. Or install a new carb kit. If you have someone who can run the boat while you adjust the carb settings while in the water be very very carefull while doing this or just take it to a boat repair shop and have them place the motor in a test tank.

Answer 3

A little more history is needed to make a recommendation. 1978 model / what HP? Has the engine been sitting up for a while? Have you checked the prop to make sure it is not bent? Are all the plugs firing? (if it is a multi-cylinder engine?) Give us some info.

Answer 4

Start eng rev up a little spray carb cleaner into each carb if one speeded up than clean carbs. Also check spark on each cyclinder.

Answer 5

Sounds like the carb needs a cleaning.

Answer 6

Well if you can tell us what HP the motor is,it would help.Heavy exhaust is likely excessive oil/gas mix.With a little more info i can give you better advice.
35 years as a marine tec.OMC/Merc?
/Volvo

Answer 7

dun noe dun care...sorry but i need to get my points up!!!
:D