excessive smoke from 60 HP Mercury outboard

ayahsoo

Recruit
Joined
Jun 21, 2007
Messages
5
recently bout a boat with a 1990 Mercury outboard 60HP.
I noticed on startup that there is a bit of what i'd consider excessive smoke from the exhaust and the idle seems a bit rough.
The seller assured that this was because the engine was being started for the first time since coming out of winter storage.

However two weeks later and when I start it (with the air muffs) to flush the engine, there is still a bit of what i'd consider excessive smoke, and the engine seems to idle a bit rough. I was kinda attributing it to the fact that this is a two stroke engine, so its expected, but i'm not sure.

Tell tale signs? Thoughs?
Thanks.
 

emckelvy

Commander
Joined
Jan 16, 2004
Messages
2,506
Re: excessive smoke from 60 HP Mercury outboard

Well, Three's aren't exactly known for smooth idle! That being said, if you haven't taken the motor out on the water and run it, the fogging oil may have not yet burnt out of the motor. It's also possible to have an oil-fouled plug so you might want to pull them and check/clean/replace as necessary.

When you take the boat out, add a carbon-cleaning additive to the fuel, such as Seafoam (if you can get it); Chevron Techron; OMC Carbon-Guard; Yamaha Ring-Free (I forget what Merc's additive is called but they have one too!).

This'll clean any deposits out of your motor's innards and may make it smoke a bit less.

Note that if the fuel/oil mix is old it may smoke more; use a quality TCW-3 rated mfr's oil or something like Penzoil Synthetic Blend (Wal-Mart has good prices on gallon jugs of the stuff). A full-synthetic oil will typically smoke less than Dino oils. If you can get non-alcolhol fuels, use them.

If you still think it's smoking excessively after getting it out on the water, you may have an overly rich idle mixture adjustment (you'll need to tweak the idle needles with motor warm and in gear). Or carb issues. But first try the additives and see how that goes.

HTH............ed
 

saumon

Lieutenant
Joined
Aug 2, 2004
Messages
1,452
Re: excessive smoke from 60 HP Mercury outboard

what have been said is right. probably unburned fogging oil. They always smoke a bit until they became warmer. Do a lake test: start it up, let warm a min or so then slowly move to WOT for a small burst then back to idle. Things should improve.

As far as oils, i've tried a few and found Quicksilver to be the one that smoke the less.

Hope it help
 
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