Lots of Smoke

[jerry murray]

Just cranked my 1988 Mercury 150hp XR4. I ran it on muffs and it is smoking real bad. Just bought this and maybe I need to do some work on it. Never had one to amoke like this. Doesn't sound bad but have not had it in the lake to see what it will do. How much smoke is ok? and what do I need to be looking at

 

[This_lil_fishy]

Re: Lots of Smoke

My 86 50hp doesn't smoke hardly at all...if at all. Unless I run low on gas then it can load up on oil. You could be mixing too much oil, or there could be a carb issue flooding it out a bit...unless it's a four stroke..then that's a whole other kettle of fish.


Ian

 

[CharlieB]

Re: Lots of Smoke

Two things

Compression test

Spark test

It can be tough to tell if all cylinders are firing while on the hose, the engine may sound fine and be quite responsive to throttle.

Excessive smoke can be a sign of a plug misfiring, not burning as much oil. The causes can be anything from a bad plug, ignition module, trigger, stator, or low compression from a burned piston, broken rings, or just old fuel.

Start with the basics, test compression and spark, if all is good then screw in a new set of plugs, fill the tank with fresh fuel and test it in the water.