Low Speed 2 Stroke operation

[88phantom]

I have a 115HP Evinrude 2 stroke. I just bought it recently and the powerhead is about 20 years old. I am about to service the magneto and replace the coils and modules to assure premium spark, but what else can I do to smooth (and de-smog) low speed operation? I would rather have a 4 stroke or a new DPI 2 stroke but this is what we can afford right now. But the smoke and low speed missing/ plug fouling etc do not impress me. We do a lot of low speed sightseeing on lakes loaded heavily with Family and Dog. I though about buying a used 9.9 or something as a kicker but the old ones are so loud.

Please feed me your experience. Can you make a big 2 stroke clean burning and pleasant to operate at low speeds?

 

[dingbat]

Re: Low Speed 2 Stroke operation

The only thing you can do is run full synthetic oil in it. I troll my 200 hp hours on end at a time and have never fouled a plug using synthetic oil. Still smokes a bit if the water is real cold.

Other than that, just do your ?low speed sightseeing? into the wind.

 

[Chris1956]

Re: Low Speed 2 Stroke operation

Idle mixture adjustment and precise timing synchronization are the keys to smooth idle. If these are set properly, smoke will be minimum and plugs will not foul.

Synthetic oil MAY reduce smoke.

 

[MercGuy]

Re: Low Speed 2 Stroke operation

I have a 1998 115 Merc and the only time it ever smokes is if I choke it too much when trying to start it.

I also spend a lot of time putt-putting around and it's never been a problem.

 

[ondarvr]

Re: Low Speed 2 Stroke operation

Smoke can vary with oils, but plug fouling is far less common you may think unless something is actually wrong with the motor. I've run large motors for very long periods of time at idle or very near it and never fouled a plug.



I wouldn't replace a bunch of stuff in the electrical system unless there was an actual issue with it.

 

[robert graham]

Re: Low Speed 2 Stroke operation

That Pennzoil 100% Synthetic Outboard Motor Oil(Walmart $27/gallon) smokes less and creates less carbon. It might help the motor to take it out and run it wide open from time to time to burn off oil and carbon.

 

[JimS123]

Re: Low Speed 2 Stroke operation

Syn oil, carb adj and precide timing go without saying.

I also run an older 2-stroke for hours atr a time at trolling speeds and had some trouble the first few years. Then I discovered Splitfire Spark plugs and haven't fouled a plug or smoked in years.

I realize that now several people will comment on my post and say that those plugs are a gimmick and don't work. All I can say is that when i started using them it was like night and day.

 

[Chris1956]

Re: Low Speed 2 Stroke operation

Hey Robert, do you have any empirical evidence that Pennzoil Synthetic oil(or any brand or type of oil) smokes less and produces less carbon? If there is an analysis, I would like to see it. If there is no analysis, it is just marketing or rumor.

 

[mrcrabs]

Re: Low Speed 2 Stroke operation

From Wikipedia, the free encyclopedia

The word empirical denotes information gained by means of observation, experience, or experiment.[1] A central concept in science and the scientific method is that all evidence must be empirical, or empirically based, that is, dependent on evidence or consequences that are observable by the senses. It is usually differentiated from the philosophic usage of empiricism by the use of the adjective empirical or the adverb empirically. The term refers to the use of working hypotheses that are testable using observation or experiment. In this sense of the word, scientific statements are subject to and derived from our experiences or observations. Empirical data is data that is produced by experiment or observation.

I tested walmart 2 cycle non synth against full synth penzoil on my eska @ 40:1, "empirical data" proved that the test tank (rubbermaid garbage can) was carboned up quickly with lots of smoke produced continually, when penzoil full synth was used after cleaning said test tank much less carbon was produced but smoked noticeably only for a short period after startup and when engine was allowed to idle for a bit and then revved, smoked for just a little bit. (note) the eska's oil ratio is 50:1 and the reason I tested this is because I try to be as careful about pollution as I can concerning 2 cycle outboards where I run, I also run full synth in my 35 year old 70hp Johnson for the last 2 years and see very little smoke although I see guys out on the river with like similar engines smoking to beat the band...I ask what oil you running...they always say "I don't know, I got it at walmart" although I would say some of them are not even sure what there mix ratio should be


I always thought that "Empirical" was the way my wife treated me
I learn something new everyday from Iboats

 

[Chris1956]

Re: Low Speed 2 Stroke operation

So you ran the Eska on a 40::1 mix for both the synthetic and the regular oil, and observed more carbon and smoke from the regular oil. Is that the salient points?

In the next paragraph, you stated that you did this because you are concerned about polution, and wanted to reduce it. Not to be arguementative, but, what are you basing your polution amount on? Is it smoke, carbon or what? Does a synthetic oil polute less simply because it smokes less, or has less carbon? That is not a statement that has any evidence behind it. You would need to run a specific amount of fuel mix thru some clean water and then check for polution of all kinds. Oil, poisionous substances, hydrocarbons, solids etc, are the kinds of things that can polute. It would need to be a straight up comparison, that maps all the elements in the water, that are from the fuel.

 

[robert graham]

Re: Low Speed 2 Stroke operation

Chris, at the end of the day, all I really "know" is from personal experience, and the Pennzoil 100% Synthetic smokes less and burns cleaner with almost no carbon. I'm still running the original NGK B8HS10 spark plugs in my 1999 Yamaha 90HP premix motor, just a nice light tan color, no fouling. I keep a new spare set of plugs in my boat but haven't used them yet. If a guy's got a plug fouling problem then the 100% Synthetic oil might be one possible solution to try...what's he got to lose?

 

[rodbolt]

Re: Low Speed 2 Stroke operation

post the model number.
those old crossflow jonnies were made in a few congigurations.
they also liked to carbon up the rings.
do a good decarb then test compression and spark.
if compression is good and spark can jump a 7\16th gap no sense in wasting money on ign components at this time.
new ones fail as well as old ones.
once the engine mechanical system are known good and the ign is known good its time to move on to fuel and cooling.
that engine does not like cold running, replace the t stats with the complete tstat kit that includes gaskets tstats and control valves and springs. while I was in it I would do the water pump kit as well.
now onto the fuel system, test the recirc check valves,check the transfer port nipples for clogging.
replace the fuel pump and fuel lines.
if yours is new enough to have fixed low speed air jets you can play with the jets and make a crossflow idle for hours and hours without excessive smoke or hiccups.
takes time but from the factory its jetted as a comprimise but if you play with them it runs much better.

 

[DJ]

Re: Low Speed 2 Stroke operation

Rodbolt is 100% correct. A crossflow, in good tune, idles very nicely and will do so for hours on end. Do everything he said.

He is also correct about ring coking. A good decarb, seasonally at least, and running Sea Foam in the fuel helps a great deal.

I've trolled with 85's and 90's for hours and never had any issues. The only crossflow, I owned, that did not like to idle was a 1973-135. However, they were sort of known to be a bit "high strung".

 

[H20Rat]

Re: Low Speed 2 Stroke operation

Hey Robert, do you have any empirical evidence that Pennzoil Synthetic oil(or any brand or type of oil) smokes less and produces less carbon? If there is an analysis, I would like to see it. If there is no analysis, it is just marketing or rumor.

I run penzoil synth in my snowmobiles and PWC. All of those engines have some type of variable exhaust valves. (RAVE valves on the seadoo, APV's on the arctic cats). On any of the cheap non-synth oils, I'm cleaning those valves at least once a season at a minimum, usually more. The carbon deposits will clog them enough they don't move.

On Pensoil synth, I still check the valves yearly, and clean them every three years. And at that point they are still vastly cleaner than the 1 year on regular, I just can't resist cleaning what little is there since they are apart already.

(keep in mind at least in the case of the snowmobiles, synthetic oil is virtually a OEM requirement, or at least strongly recommended, that you run arctic cat powervalve oil, which is synthetic, on all powervalve engines)

 

[mrcrabs]

Re: Low Speed 2 Stroke operation

That is not a statement that has any evidence behind it. You would need to run a specific amount of fuel mix thru some clean water and then check for polution of all kinds

I agree with you completely, I do not have any way to test the water except visual inpection, I did use clean water at each test and made noticed that the water was much cleaner to the eye with full synth, my only evidence was by visual observation.

 

[88phantom]

Re: Low Speed 2 Stroke operation

Thanks for all the replies. This weekend after replacing the plugs with NGK's I removed all the coils and cleaned the grounds. They were in bad shape. Two of my coils have the cores rusted enough to distort the shape of the core, which could effect voltage performance, I will replace those. the engine ran alot better with new plugs and clean grounds, but still misses at low throttle, but not at idle. I will look to the carbs.

I wish I knew the model of the engine, rodbolt, biut I have the misfortune of buying a 97 with a salvage powerhead on it of unknown vintage. It appears they painted the powerhead black over light blue and white, although rust colored paint shows here and there. no telling, although the previous owner claimed it was an 89' model 115 powerhead.


Mostly, I am glad you guys are proving that the big 2 strokes can run and burn clean when in tune and using good oil. I will do a good go through on this engine instead of planning on buying a 4 stroke for big bucks.

 

[DJ]

Re: Low Speed 2 Stroke operation

Get the NGK's out of that John/Rude. They don't like them for whatever reason. Champ's only.

Personally, I wouldn't put Champ's in anything but an outboard or lawn equipment but John/Rudes love them.

 

[rodbolt]

Re: Low Speed 2 Stroke operation

NGK plugs use a resistor, most the mid 80 and up jonnyrudes like the Q series champion. Q is inductive not resistive.
I won a 100 dollar bet some years ago that my 85 120 looper with an OMS pump could not idle from dock of the bay in kitty hawk NC to the manns harbor bridge, took about 3 hours and more refreshing beverages than I care to disscuss but I collected my 100.
all it takes is a willingness to lean how and why all them thar parts are thar, and deal with the fact its a production motor thats sold round the world for many altitudes,air temps barometric pressures and humidity levels.
all can affect an internal combustion articulated rod gasoline fueled engine.
when it left the factory everything is set as a comprinise.
OMC did not know if that motor was going to end up in wyoming at 5000 ft above sealevel or down in texas at 2 ft below sealevel
all left the factory jetted the same.

 

[outboardnut]

Re: Low Speed 2 Stroke operation

Fuel quality comes to my mind. Make sure you are running off of fresh, good quality fuel.

 

[88phantom]

Re: Low Speed 2 Stroke operation

Good point on the fuel. First tank in the boat was how???? old?

Rodbolt, are the jets adjustable or do you have to change the jet plugs to resize?

I have used NGK and champs on my little EV, could tell much difference. I will def. consider going back to champs. Some of the parts stores around here only carry NGK is why I have them.