Mercury 90 ELPTO smoky when started cold

[dandreye]

Hi All,

My 2000 Mercury 90 ELPTO is quite smoky every time it is started cold e.g. as soon as next morning after use (or later).

Is that because of some residual oil in the engine? How does it get there or accumulate there?

Is it the way these engines are designed to work or sounds more like an issue?

As the engine warms up the smoke goes away.


Many thanks in advance,

Dmitriy

 

[Silvertip]

Re: Mercury 90 ELPTO smoky when started cold

It's the nature of a two stroke engine. Oil is mixed with the fuel for lubrication since a two stroke doesn't have an oil pan filled with oil. Oil is mixed with the fuel either in the tank or via the oil injection system. Once the engine warms up the smoke lessons. Oil smokes when it burns. Semi-synthetic smokes less. Full-synthetic smokes less than semi-synthetic.

 

[lncoop]

Re: Mercury 90 ELPTO smoky when started cold

I have the same motor circa 2001 and it does that. Since you're not having any other issues it's most likely just residual unburned oil.

 

[dandreye]

Re: Mercury 90 ELPTO smoky when started cold

Silvertip:
lncoop:

Thanks for your replies. Do you know the approximate % of oil in the mix during the cold start assuming that the fast idle lever is half way up? Afaik when riding at WOT it's 1:50 - is even more oil injected during the cold start than that? I don't seem to see much smoke when riding at WOT although it's probably a lot harder to notice.

Reportedly the design of these engines allows the residual oil sprayed inside the powerhead to accumulate at the bottom and leak out through the bottom carburetor into the attenuator when the engine is tilted up, stay there and leak back into powerhead when the engine is returned into the working position before the cold start, thus supplying a lot more oil into the bottom cylinder. It sounds logical to me as why have a gasket right in the bottom between the attenuator plate and its cover (#3 at the diagram attached). But if so I would expect to see many posts mentioning this as all 2-stroke engines with such design would have been affected.

 

[Handyman1]

Re: Mercury 90 ELPTO smoky when started cold

Hi i always had a two stroke different motors Merc, Johnson, Evinrude, Yamaha they all smoke a little more when i started them cold. I guess it is normal.

 

[G8trbait]

Re: Mercury 90 ELPTO smoky when started cold

I have a 2003 90 ELPTO and I believe it is 80:1 at idle and 50:1 at WOT

 

[strokersquid]

Re: Mercury 90 ELPTO smoky when started cold

My 100 Merc, Seadoo,Yamaha PWC, every 2 stroke motorcycle I've had. All smoke when started.Just like 4st engines "steam" in the cold until they warm up.

 

[79Merc80]

Re: Mercury 90 ELPTO smoky when started cold

One of the biggest reasons they smoke more when cold is the fact that they need a lot of choke/prime to get started. That's a lot of extra fuel/oil being sucked/sprayed into the engine than after it's fired up, and once that is burned off/cleared up, then it doesn't smoke as much.

Once you get it running and warm. Hit the choke/enricher a couple of times and it will smoke again.

HTH, Craig

 

[dandreye]

Re: Mercury 90 ELPTO smoky when started cold

Hi All,

Thanks everyone for your replies. I'm now helping someone who's complaining about regular oil leakage when their 60ELPTO is tilted up. So is it true that the design of these engines allows the residual oil sprayed inside the powerhead to accumulate at its bottom and leak out through the bottom carburetor into the attenuator when the engine is tilted up, stay there and leak back into the powerhead when the engine is returned into the working position? That would definitely contribute to both smoky cold start and residual oil leakage. It sounds logical to me as why have a gasket right in the bottom between the attenuator plate and its cover (#3 at the diagram above).