Heads up for four stroke owners on no wake lakes.

Once in a while I will see what I call an anomaly come in the shop, but when I see the same thing three times in one month then there is an issue that needs to be addressed and made known.
The issue this year is four stroke motors of various horsepower ratings that are most often on no wake lakes where motor RPMS are kept low to keep boat/pontoon wakes within an acceptable limit.
So far I have had a 90 carbed , 115 injected, and a 25 injected motor come in with severe misfires and performance issues all around.

So whats going on??? the motor never gets much above an idle and they never get a chance to get warmed up to the point that the detergents in the oil and gasoline will do their jobs keeping the motor clean.
What I have seen so far is sticking intake valves, rings stuck so bad that they can no longer seal the cylinder and, oil that is so coagulated that it wont flow through an oil filter, no kidding!!’
The motor that had the pudding for oil was in a one year old 25 HP Merc that only has ten hours on it, warranty will not cover this and I can only hope the motor will last for the young man who spent his savings buying it, I applaud him for shutting it down when the light and alarm came on.
He did get stern instructions on how to check the oil everyday that the selling dealer didnt teach him, poor kid didnt even know the motor had a dipstick!! and I will keep my thoughts to myself about the selling dealer!!
The 90 HP, stuck intake valves in two of its four cylinders, fifty hours on the motor since new and its nearly twenty years old already.

The 115 HP motor, injected, close to sixty hours on it, never been off the little no wake lake near the shop.
It took a while on the dyno running Neutra 131 in the fuel and in the crankcase to clean it up and free the rings, I was lucky that it would build just enough compression to start and run.

Whats the answer for this?? get those motors on a big enough lake you can wring em out once in a while, let the detergents in the oil and fuel work!!!

Edit to add, fuel dilution of the oil and condensation are a large part of this equation as well.
The motors need ran long and hard enough to clear these things out.

I have a dumb question since I have no mechanic skills Sheldon…
Why doesn’t this happen as well to 2 strokes?
Or does it?
Just curious…

The only dumb question is the one that doesnt get asked!!
Most of the four stroke motors have the oil pan/reservoir mounted at the bottom of the engine where the oil is kept, that reservoir also happens to be the coolest running location of the motor.
Being at the lowest point of the motor unburnt fuel and condensation will settle there and it will get blended with the oil when its picked up by the oil pump and pumped through the entire engine.

The oil just gets barely warm and the detergents cant keep it clean as they need heat to work or the cycle continues, wash, rinse, repeat in a sense.
That crud starts to adhere to moving parts in the motor and will continue to build to the point stuff quits working.
Intake valves run cool as incoming air keeps them that way, this is why you will see the problem with them first.
Rings suffer with crud build up from both sides of the piston, one on the combustion side and then the crankcase side.

Two strokes can suffer with sticking rings if let go long enough, build up of deposits in the combustion chamber can be severe enough you will get preignition, this is when carbon will glow red hot igniting the incoming fuel/air charge, if ran long enough that way it will burn a hole through the pistons top.

Crud will build up on reeds, ports, in bearings, so they are not totally without problems.
It helps that a two stroke fires every time the piston comes to the top of its stroke, it does by its nature run a little hotter.
Also, a two stroke doesnt have an oil reservoir where crap collects like it does in a four stroke.
Hope that helps!!

Definitely makes sense. Thanks for the tutorial

115hp operated almost solely on a no wake lake….doesn’t make sense. Sounds like an excellent reason for an electric outboard…

I hear ya crc, that motor is on a 22 foot toon and it came with that motor when the customer bought it, and that is not the biggest one on a 400 acre lake!!
Kinda like who has the biggest tater in the bin thing.
I service many rigs from another private lake where there are 26 foot Bennington pontoons and tritoons that have bigger motors yet!! at least there when there is room they can run wide open for an entire half mile….. or in circles, poor fish.

I’ve had this problem with my Honda, but never with my Yamaha high thrust. Do you think it’s because Yamaha has an rpm reduction system? Just curious.

Would running Sea Foam regularly help/stop this problem or waste of $?

Just a question. I don’t want to redirect this thread, but I am not familiar with
“Neutra 131”.

You seem to have some experience with it. It is described as a fuel stabilizer.

What is your experience and can you compare it to Stabil, Seafoam, or etc…

Thanks

I’m curious to hear the opinions on sea foam. I use it on a lot of my small motor stuff but have heard both side of the spectrum on weather it’s useful or not, more so when talking about carbs.

Here is a link to the Neutra I use, it has many more uses than what is listed in the link, for example I will use it to purge a crankcase on engines that have been using another brand of oil and I am switching it to Schaeffers oil.
The purging cleans out all of the crap in dirty engines and in severe cases I have to purge them twice.
https://www.schaefferoil.com/neutra.html

The question was brought about seafoam, in MY opinion, it is over advertised, over used, and over rated, it is a potent solvent and it does have its place but not every dang tank full !!
Heres the deal, if you are buying quality gasoline it will depending on the blender have anywhere from 90-120 different chemicals in it that is supposed to keep your engines fuel system clean enough you shouldnt need any additives on top of those already present in the fuel.
That said, our fuel degrades so quickly today we need something once in a while depending on how quickly you use up the fuel in whatever application.
I only recommend the use of Neutra when a system has been polluted over a long period of time or when you are going somewhere you dont have access to your favorite and trusted brand of gasoline.
I highly recommend it for winterizations/summer storage as it will keep gasoline much fresher than anything I have seen or used in over forty years of doing this.

Another question was asked about the difference between a Honda and a Yamaha having problems, I will be honest and say I am not familiar with the high thrust mentioned and I can only guess that is do to different gear ratios allowing the engine to spin more revs which in turn will allow it to get warm enough it doesnt suffer like the other.

I have tossed several thoughts around on how to prevent the problems I mentioned on no wake lakes or for folks who putt around way too much.
Those ideas are, put on a smaller prop to make the engine turn more revs, but sure as crap about the time they do that they will get the idea to go to a bigger lake without putting the bigger prop back on and scatter the motor.

Another idea was try to find or retrofit higher temp thermostats so that the motor will run warmer, same problem, you are asking the owner to remember that and if they are not diligent in watching things, the motor gets hot and goes kablooey and I am at fault.
Other ideas I will keep to myself as I dont want someone trying them.

Same can be said for kicker motors! Run em’ hard every now and then…

When I bought the Solara with the Yami 150 sho on it, Dean told me “BK, I know the way you drive. You need to get on this motor occasionally.” Guess I can put away the step stool.

IB good post!

I don’t know what’s more interesting, this unusual problem with 4-stroke motors, or like someone else said, why so many people are buying boats with large motors to be used on a no-wake lake.

Justin Donson wrote:

I don’t know what’s more interesting, this unusual problem with 4-stroke motors, or like someone else said, why so many people are buying boats with large motors to be used on a no-wake lake.

Pontoons and tritoons have really evolved. It seems everything less than ~5 years old has a 200+hp hanging on the back on the river. Twin setups are becoming more normal too. They used to be something you’d really stop and look at, and now on a busy weekend they’re fairly normal to see on tritoons.

I resolve the issue by getting the Cummings warmed up on the way to the cabin, that’s seems to have resolved that issue with the 4 stroke😉

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Sigh, the problem like the energizer bunny keeps on going, good job you bunch who invest in ethanol production, you are not only ruining motors, you are personally responsible for the devastation of tens of millions of acres of pasture that should have never seen a plow, millions of trees in water ways that were dug out and burnt, and more importantly, the habit for wildlife that thrived in the fence rows and ditches that are now farmed into oblivion.

Good posts Sheldon (22&23)!
Ethanol it’s the best! LOL!!

Iowaboy1 wrote:

on no wake lakes where motor RPMS are kept low to keep boat/pontoon wakes within an acceptable limit.

Sounds like an opportunity for someone to come out with a 2 pitch prop for these no wake lakes.