Dingy Outobard Yamah 15HP is a POS

[Liquid Asset]

Possibly one of you can help me. I have a 15HP Yamaha 2stroke outboard for our inflatable. I have come to believe this thing is a POS. It has appeared that it is not a hearty as the old 2 stroke outboards of the past. Ever time I take this thing out I have to do something to make it run. Most of the time, I have to repair teh carereuter. It seems that there is a flaw in its design. The float pin is square and it is in a square hole that is too bit. The pin twists just enough to get jammed.

I know that part of the problem is that it does not get used a great deal, but wehn I used to have a 15hp johnson on a jon boat, it could sit for 6 months and you could go out and it would start right up.

Ever time I use this, I disconect the fuel and burn out all the fuel as the Yamaha deal has instructed. I have taken it to them twice to get this repaired. I also flush it with fresh water if it is going ti sit for more than 1 day.

If I do not find a solution for this quickly, I am going to fix it and then sell it. It is hard to own a outboard for our dinghy that does not store well because it is common for us to not use it for 2 months at a time.

I am at a loss for what to do, the dealer is frustrated, and I have 2 other people on our dock who have had the same issue with the same model engine. both of them have since sold theirs. Please let me know if you have any suggestions.

 

[BUSTER]

Your problem may be congenital "the motor is a POS" or this: It seems like everyone is having trouble with outboards that aren't used often since the ethanol to gasoline ratio has increased. The fuel has a very short shelf life.You are on the right track running it out of fuel,but you also should add stable to your fuel before you run it dry if it is one of those times you may not use the motor for a while.Even though the engine seems to run dry there is always a small enough amount of fuel left in the bowl to cause a problem when it sits there.
I've been through the exact routine you are going through before I started following my own advice.

 

[SeaEric]

The problem is more likely the unused gas left in the tank. Once it has phase separated, its done. Unlike in the old days, adding fresh gas to bad gas does not fix the problem. Dump the gas and use fresh each time and you may find your problems fixed. Or perhaps the OB is just a POS.

BTW, fuel stabilizer will not prevent phase separation.

 

[Liquid Asset]

Ok, if I give in to your thery about it being the used fuel in the tank, then I have to say that this problem goes back 3 years. It just has finally gotten to me because we were in a place that I needed to be able to use the dingy and did not have to time to do the repair.

I have added the stablizer additive to the fuel. The fuel is 2-3 months old.

please let me know if you have any more thoughts.

 

[Liquid Asset]

Eric, What is the estimated time frame for phase seperation? I am not familiar with this problem. is there any additive that will stop this that you know of?

 

[krush]

If I understand you correctly, you are saying the inlet needle is getting stuck. If this is what is happening, it's because of the ethanol. I've rebuilt tons of carbs because the damn ethanol swells up the seals and parts inside that weren't made to handle alcohol.

The needle and/or seats often swells up and gets stuck. I've been stranded a couple times because of this. Usually I can bang the side of the carb with a wrench and squeeze the bulb at the same time and get some gas into the bowl.

My suggestion: Rebuild the carb with new parts. If possible, as the dealer if the parts are compatible with ethanol.

Yamaha makes the best engines out there in my opinion. You can give it to me if you don't want it!

 

[NAN-PO 41]

We bought a new 18hp Tohatsu 4 stroke and I made the mistake of letting it sit for a month without using it. You guessed it. I had to have the carb overhauled. The fuel in the carb had turned to jelly. The new fuel is crap. That was Summer before last and since then I run the engine once a week and dump the fuel tank into my truck every 2 weeks and drain and clean the carb for Winter. Yes it is a pain but the engine runs every time now. It seems that the smaller the engine the more prone they are to this problem. Makes sense, smaller passages and all.
Fred

 

[Pascal]

yep, Yamahas are usually excellent outboards... fuel is usually the problem and lack of use.

 

[SeaEric]

Re: Dinghy Outboard Yamaha 15HP is a POS

There is no specific time frame for phase separation. It relates to several factors, mainly the availability of moisture, either in the air or directly, to enter the tank. There is no additive that will effectively prevent phase separation from happening.

Think of the ethanol in your gas as a sponge. It is constantly attracting and absorbing water. The water enters the tank as humidity in the air through the vent, or directly through a bad fill or other entry point. When the ethanol absorbs the full amount of water that it can hold, phase separation occurs. The result is a layer of water/ethanol mixture on the bottom of the tank that will not burn or mix with new fuel. The remaining gas floating on the top is octane reduced, and will therefore cause serious problems if run through an engine.

In a 2 stroke, the reduced octane gas inhibits the lubricating properties of the oil in the gas mixture causing lubrication issues.

 

[REBrueckner]

In December I brought home my 1999 15 HP two cycle Mercury...it stopped cold in the fall while I was running....I bought an entire carb rebuild kit almost $95!!!! When I got the carb apart what did I find: the float was stuck in the closed position with the needle valve stuck in the the closed position...the float was ok it was the needle valve that was stuck. I always run my engines out of fuel and then drain the fuel filter cartridge as well...the plastic holder which holds the fuel filter as fuel enters the carb.

This needle valve has a "rubber" neoprene/black tip which appeared to stick to the metal circumference of the fuel passage its supposed to meter.
Just to be sure, I changed needle valves but no other parts even though the old needle valve looked perfect....I have not run the engine yet but I'm 95% sure I found the reason for the sudden stop... the carb was clean,dry,no sludge, nothing evident, looked brand new inside....

In the past years and engines a bit of water in the fuel would inevitably lead to a prior type of needle valve malfunction where the tip of the old style needle valve was metal...silver color, rather than black neoprene or whatever it is they use currently. It would corrode and an engine would start running rough at low spepeds....
I liked that old style needle valve a lot better. But surely with today's technology somebody ought to have a better material than either I have described....

 

[saltshaker]

I had the same problem with my Yamaha. First time it happened, I was out on the dinghy and it stoped running. Would not restrart until I cleaned the carb out. This was at least 10 years ago so you can't blame ethanol for this problem. I too run the gas out before storing it. I also use a small tank and try to use it up before it gets stale. I also shake up the tank before starting to insure the oil is mixed well with the gas. This seems to work but the carb still needs service once or twice a year.

 

[rrrestorer]

Over the years I've learned that in the spring I take and drain the gas out of the tank, spray the hell out of the carb with carb cleaner, take the spark plugs out, spray a half a can of carb cleaner into the tank, pull start or electric start without the plug until the carb cleaner is out of the tank and lines, put fill the tank up with fresh gas, put the plugs back in and it starts like a brand new engine again.
Cant tell you how many snow blowers, little gas generators, weed eaters, and leaf blowers I've thrown away before I learned my lesson. Oh, it helps if you do this before you start messing with the adjustments, which shouldn't have changed over the storage period!

 

[krush]

Before ethanol, the main problem was old fuel turning to varnish in the carb. It doesn't matter if it's a lawnmower or an outboard, people use them a couple times a year and let them set. 85% of the time when people brought me motors that didn't run, it was just a dirty carb.

Now that ethanol has surfaced, it's not JUST dirty carbs, it's that the gaskets and rubber in the carbs swells up or get's destroyed by the ethanol.

Phase separation is another problem, but that's easy to cure.

 

[Nonchalant1]

Strange thing... My dinghy has a 1997 Yamaha 40HP 2 cycle motor (oil innjection, not an oil-mix type). It has never had this problem and I have stored it years for for 5 or 6 months over winter with a half full gas tank. Every spring, I put in new plugs and run it. It takes a while (30 sec) to start and a few minutes running fast to get all three cylinders running good, then it's good all season. If I let it sit a month or two, I have to go through the slow startup and run fast a few minutes, but then it just works fine. We usually use it only for a few days every month.

The only problem I've had was a blown fuse to the power remote controls which completely stopped it and I couldn't find the fuse holder to save my having to paddle some. Cost me $40 to have a tech show me where they buried the fuse holder.

So maybe it's not Yamaha, it's that these carbs are different and I just happened to get one that doesn't mind ethanol.

Doug

 

[Vincentc]

I have gotten completly away from 2 strokes. My inflatable has a 2.5 suzuki, which weighs about 30# and so far has started without complaint.

I use my pressure washer very infreaquently and it always has problems with fuel. I pour the old gas out and refill with about 50/50 "Seafoam Gas Treatment" and new gas and after some coaxing and about half a tank it works fine.

Vincent

 

[George]

one question. Do you store it laying it down or upright?

 

[REBrueckner]

Storage: makes no difference as long as the head is kept above the water outlet...as,for example, when the engine sits on its back as designed...letting the prop sit higher than the head is bad because water may run where you don't want it....back into a cylinder....and sparying some fogging oil in each cylinder isn't a bad idea...although I have only remembered to do it one year....

 

[Liquid Asset]

I have always said that yamahas are reliable, but I think I have come to learn that this is only in their larger engines. The problems people have seem to only be with their small outobards ie.9.9 & 15HP.

Most people only use these engines a few times a year. There has got to be a solution to this. Most cruisers swear by these engines, and if they were used often, I could see this not being a problem. But I dont use it as often as most people. We sportfish and just dont use it all that often. A lot of times, we just tow a 17' Aquasport and never put the inflatable down.

So there has to be a solution. There are many other people that dont use their outboard often and I do not want to throw good money after bad again. If these are just a POS, then I will fix it sell it and get another engine. I am tired of having to work on it.

 

[Liquid Asset]

Today I called a mechanic I know that is a Yamaha Dealer. He has told me that Yamaha puts extremly small jets in the carbureuter of their small engines and they are highly suceptable to this problem. His actual advise was to bring it to him, let him get it running and sell it. He said go find a used something else and quit messing with the Yamaha. He said that his experience is that they are terible tender motors because of the problem I am having. People just do not use tenders enough.

 

[solanderi]

Hey Pat,

Just curious as to the end of your Yamaha 15hp story. Did you buy something else ? What motor did the mechanic recommend ? Thanks, I'm hoping to learn from your trials.

Greg