Yamaha let's me down again

[sherwin]

I have had repeated problems with my Yamaha T9.9 dying out for no obvious reason and refusing to restart. Last year, I changed out all my fuel lines and put in an inline 10 micron filter. That seemed to help until
a few days ago when it suddenly died out on Lake Michigan. I thought it had run out of fuel, so I added a couple of gallons to my 6 gallon feed tank. It started and ran for about a half hour, enough to get me inside
the Racine Wisconsin harbor. Just as I got my main sail down, it died and
refused to restart. I would run for about 30 seconds and then slowly putter out. I was drifting towards the rock harbor wall and just had enough time to raise my main and tack up to a vacant mooring can.
I put in fresh gas into the empty tank at the beginning of the season about one month ago. The gas I added on the lake was fresh high octane
gas purchased a week ago. I did not add any Stabil to this last batch of
gas. My filter with a water separator did fall from it's bracket, but I don't know if this causes water to be introduced into the gas line. If it is water,
or bad gas, do I have to drain the whole tank (pain in the butt)? Does the
carbuertator have to be stripped down, or are there any other simpler measures I can take before tearing things apart? I bought the latest gas at a reliable neighborhood station, but could it be bad enough to cause this kind of failure? Does the higher octane gas help or hurt this kind of
problem?

I cannot depend on this engine anymore for reliable power. Even with a sailboat, I cannot bring it back off the lake and maneurver it to my slip
down the Root River and through a bridge with fixed opening times. I have owned a British Seagull and a Chrysler Sailor engines, both two strokes, and never had these kinds of problems. These four strokes are
like pampered children and can be dangerous when they go out at the wrong times.

Sherwin

[sherwin]

Yamaha let's me down again

Forgot to ask, I only have about 20 hours on my inline 10 micron filter.
How long can I go before replacing it? What about the fuel filter in the engine itself? How many hours of running can that go assuming the normal amount of dirt in my six gallon tank? If the fuel filters were blocked, would that allow me to run the engine for 30 seconds before it
sputters out?

Sherwin

[99yam40]

You could be poring it in when you fill the tank or the tank/ lines are degrading and coming apart.
The motors are designed to run on 87 octane, higher octane burns slower and may not all burn inside the cylinders. This means you may not get all the power out of your fuel, some burning in exhaust.

There is no normal amount of dirt in fuel, it should be clean. If you have nasty fuel it needs to be drained and clean/ replace the tank and lines.
best to pull and clean carb to make sure all passages are clean. See what you find in fuel bowl of carb.
4 strokes have smaller passages that plug easier with trash,water,or dried up fuel. running often and keeping clean fresh stabilized fuel in it will help. do not let it sit and let fuel dry up in carb or lines

[sherwin]

As a follow up, I am still not clear about what bad gas really is. I understand that gasahol is really a solvent and could dislodge dirt in the fuel system. I don't think that this dirt is getting past my 10 micron filter.
The other problem often mentioned is gas going bad by just standing idle, and the fix is to put in something like Stabil to prevent it. What actually
happens to the gasahol when it goes bad? Does the alcohol fuel mixture turn into something else, like a gummy substance? Can that bad gas pass
through my filter? I am going to try a new 10 micron filter cartridge and
a new Yamaha engine filter and replace the gas in the tank with fresh gas.
I may have to tear down the carb anyways, and if that is necessary, maybe I will see exactly what is keeping the engine from running.

As an aside, ordering parts from Yamaha Outboard Parts can be slow on delivery. Mine was sent out July 16 from Florida US First Class mail. It
did not arrive in Illinois until July 22. The suggested delivery time of 2 to
3 days is just that, a suggested time. Next time I will pay for a faster delivery, if I need parts in a hurry.

[jb123]

it ran fine until you ran out of gas and water separator fell off mount... and whom do you blame for this ?

[redmanja]

this site will explain gas problems-http://www.fueltestkit

As a follow up, I am still not clear about what bad gas really is. I understand that gasahol is really a solvent and could dislodge dirt in the fuel system. I don't think that this dirt is getting past my 10 micron filter.
The other problem often mentioned is gas going bad by just standing idle, and the fix is to put in something like Stabil to prevent it. What actually
happens to the gasahol when it goes bad? Does the alcohol fuel mixture turn into something else, like a gummy substance? Can that bad gas pass
through my filter? I am going to try a new 10 micron filter cartridge and
a new Yamaha engine filter and replace the gas in the tank with fresh gas.
I may have to tear down the carb anyways, and if that is necessary, maybe I will see exactly what is keeping the engine from running.

As an aside, ordering parts from Yamaha Outboard Parts can be slow on delivery. Mine was sent out July 16 from Florida US First Class mail. It
did not arrive in Illinois until July 22. The suggested delivery time of 2 to
3 days is just that, a suggested time. Next time I will pay for a faster delivery, if I need parts in a hurry.

this site will explain gas problems-http://www.fueltestkit

[sherwin]

At the boat today, I replaced the in line filter in the fuel line and the internal engine filter. The engine ran better, but it will still not maintain an idle for more than 30 seconds. I believe the high speed jet is ok, because I reved it up in gear and their was plenty of power. However, when returning back to idle, it ran for a few seconds and died out. I suspect the low speed jet is the culprit. I really don't relish the task of trying to remove my carburator from the engine while hanging out over the rear transom. The engine is too heavy (103) pounds, and is bolted to my lifter. I would have to pull my boat from the water to remove the engine. I have followed the suggestions of Yamaha by changing my fuel lines and putting in a 10 micron filter inline, yet this carb is blocking up anyways. These fine jets are just a problem waiting to happen. Yamaha has not given me a good suggestion yet on how to cure this problem.

Also, my Racor25 -02 10 micron filter is a sham. It is all plastic and made in China, but the price does not reflect this. Their instructions tell you not to use tools to open the unit for filter replacement, but I don't think a 300 pound gorilla could have done it. I had to use a wrench. Removing the filter element itself was again not a simple twist. The filter is threaded into the case in a fashion where you have to destroy it to get a wrench on it for unscrewing. Placing the plastic bowl back on is almost as difficult as removal. Going to West Marine for a replacement filter was a waste of time. They don't carry my Racor or any other filter that can be identified as 10 micron.

I was much happier with my old 2 stroke engines that did not run as smoothly, but did not fowl up like these newer 4 strokes.

I did not see any water in the water separator portion of the Racor and I'm sure my Mobil station here in Illinois is using the correct amount of ethanol in their tanks.

[99yam40]

You can always go to your local Yamaha dealer and purchase the parts and filters from them for your motor. Sounds like the US mail is the one you have a problem with for slow delivery.
If you do not want to pull and clean the carb then see if some one at the marina will do it for you. Maybe pull the motor off using another boat to work out of.
Hopefully you can find someone that is knowledgeable on Yamaha motors and has the proper tools and equipment to do it right, but it needs to be cleaned and then adjusted properly after reinstalled.

[Operaman]

The Yamaha water seperator filter assembly is superior to the Racor. It is also more user friendly to swap out the filter.
I had a Racor on my Mako, swapped in a Yamaha filter assembly. The Racor is now on my Whaler.

Is your fuel tank portable or built into the boat?

By the way, even the 2 strokes from the 80's till now have very small jets in the carbs.

I also sail and understand that the engine must be reliable.

[sherwin]

I managed to get Racor to agree to send me a replacement inline filter. It is their el cheapo model made entirely of plastic, but for now, I will stick with it to save some money. I may decide to replace it eventually with a Yamaha filter. Interestingly enough, Racor admitted that this filter, and possibly some of their older model filters have problems with the gaskets and the filter's disintegrating after long exposure to alcohol. I saw no evidence of this in my four year old filter, but the particles could be too small to see.

My tank is an inheritance from my older Chrysler outboard. It is metal and
of much better construction than the plastic one that came with the original
Yamaha. It is a six gallon tank that just fits into a locker. The Yamaha 6 gallon tank was just a tad too big to fit in the same locker.

I talked with Yamaha customer service in Atlanta. Although the rep was a bit gruf with me, he had one interesting suggestion. To avoid removing the carb from the boat, he suggested to unscrew the air mixture screw from the carb and try blowing some compressed air through that opening, hopefully dislodging any dirt stuck in the jets. It's worth a try. As far as help from other mechanics, Yamaha in Racine and Kenosha are too busy to work on my motor. Reefpoint Marina mechanics are afraid to touch it, so I am stuck
fixing it myself. I removed the carb once before while it was on the boat, but it was almost a miracle that I didn't drop any parts into the water.

Some of this problem is due to Yamaha making their carb bodies out of aluminum. The aluminum is broken down by some additives in the gasahol and leaves a white powder. That may explain the blockage in my carb jets.
Why can't Yamaha make their carbs out of a different material?

In any case, I hope I can clear the jets without removing the carb, for now.
At the end of the season, on dry land, I can more easily work on the carb.