2009 F40TLRB problems - HELP!!

[vroppelt]

I have a 2009 Yamaha F40TLRB motor, installed new in spring 2010 by an authorized Yamaha dealer, complete with new controls, wiring, and all new fuel lines and (10 micron) fuel filter. I have continuing problems with the carbs and accellerator pumps clogging with small debirs. My (Yamaha authorized) service guy is telling me that there is basically a design flaw in these motors, with ports/passages that are too small, they will continually clog up and need cleaning. I have had him out pretty much every 30-40 hours to clean out these damn carbs (and I do about 150 hours/year). I need suggestions on other approaches to reccommend to my service guy, or advice on how to deal with Yamaha to get this 'design flaw' corrected or replaced.

Please dont suggest that I am getting bad fuel, or that there is a problem with my fuel tank, that is DEFINITELY not the issue here...

[Inducted]

There is a service bulletin dealing with this issue that may help. Try to get new carbs or at least new float bowls if it will not run properly. Treat your fuel per yamaha specs. Also when you are done using your motor run it out of fuel each time by disconnecting your fuel line then attach a" fuel fitting only". exactly like the one on your fuel line. This will help it in running out of fuel completely. These carbs need a lot of TLC. Good luck.

[vroppelt]

Thanks! I'll pass on to my sevice guy, not sure why he wouldnt be aware of this though.

Having to run all the fuel out sounds like a riduclous 'fix' for a new motor, but I'll give it a try.

Thanks again!

[99yam40]

There are a lot of opinions on running the fuel out by running motor until it dies, and mine is you can never do it completely as the motors with multiple carbs will never run out of fuel on each carb at the same time. Which will leave some fuel in some of them and it will never suck all of the fuel out of the fuel bowls on any of them if the pick up point is not made into the bottom of the fuel bowl itself. Not sure on the 40 4 stroke but on the 2 strokes it is not made into the bowl.

Not sure where you are located, but if particles of something is getting into the carbs plugging the passages they are coming from somewhere.
If you have a 10 micron filter/ water separator before the motor and the filter screen on the motor, you either have something still getting by them or there is something breaking down the fuel lines after and that is what is plugging your carbs. There are fuel lines that are not compatible with ethanol fuels, but do not think that would be the case on that new of a motor or even if you use the ethanol fuel.
How old if the tank and lines?
Do you stabilize your fuel before leaving it sit or all the time?
And how long do let it sit between uses?
How old does the fuel get before replacing it?

[vroppelt]

Thanks for your reply. I understand what you are saying, but just dont see how it can be, in addition, my service guy is saying that the ports/passages on these carbs and accelerator pumps are small enough to trap 'stuff' that is much smaller than 10 microns.



To answer your questions;

How old if the tank and lines? 1 year. Had all new lines installed at the time the motor was put on, then had them replaced last sping AGAIN, thinking maybe the original dealer didnt really replace them like he said (but he actually did). The tank is an above deck red poly 9 gallon tank, replaced last spring as well.

Do you stabilize your fuel before leaving it sit or all the time? Yes. I use star-tron for short term, and sta-bil fo longer term. I use the boat A LOT though, so with a 9 gallon tank, it never sits for more than a coupl weeks anyway. I stabilize the fuel over the winter with sta-bil, but the past tw years I have drained it out anyway and started over with fresh fuel (because of the problems I'm having)

And how long do let it sit between uses? During the season, the boat rarely sits more than a day or two between uses. Its in my backyard, so I (or my kids/wife) run it almost every day.

How old does the fuel get before replacing it? Again, I use the boat a lot, so I'll burn through the 9 gal tank weekly, or maybe two weeks at most.

I have tried getting fuel from only my marina, then tried getting it only from a land based gas station (with portable containers). I have tried replacing every fuel line and even the tank. I just cant see how its a problem with the fule or the 'external' fule system. I originally doubted the service guy a bit when he told me that its kinda a design flaw with these REALLY small passages in the accelerator pump and carbs, but I am starting to think he is correct on this...

If running out the fuel is a solution, I guess I'd do it, but it seems like something that I shouldn't have to do with a new motor.

Do you happen to have acces to the service bulletin on this? Not looking for a copy, but looking to find out kinda what its says...

[99yam40]

Sorry, I have not seen the service bulletin he spoke about,
and with you constant use of the motor it does not sound like running the fuel out each time would be a solution for your problem. The fuel does not sit long enough to evaporate or absorb enough moisture from air to harm the fuel. I have heard that the 4 stroke 40 carbs are a pain because of the small passages.

Did say you run a boat mounted water/fuel separator filter? Maybe change it out to a smaller micron filter
Hard to believe that anything that would flow through a 10 micron filter would plug passages, but I believe they do make a 3 micron.

[Inducted]

Sorry, not a service bulletin but a Technical TIP. It is in the 2009 yamaha marine technical guide and it deals with proper cleaning of all circuits and modifying the carb for cleaning the pump circuit nozzle. Your dealer can look it up for you.

[boats.net]

There wasn't a service bulletin issued on it but there was a tech tip on proper cleaning of carbs to ensure all the passages and jets are properly cleaned and checked before reassembling carbs, your dealer will have a copy of tech tip. There are very small passages in accelerator pump and low speed circuit of carb that are hard to clean out, the ultrasonic cleaners work very well to clean carbs.
In most cases what we find in carbs is gum and varnish residue left over from old fuel once it evaporates from carbs. The only way to eliminate that is to manually drain all gas out of carbs before storing outboard for any length of time.
Not sure where you are located but here in south Florida if a gas tank with ethanol blended gas is stored in direct sunlight the gas will go bad in a matter of weeks(extreme heat breaks gas down quicker) and gas evaporates faster from carbs if in direct sunlight as well.
We have non-Ethanol gas available to us here and when use it and add Yamaha Fuel Stabilizer & Conditioner Plus to gas it has helped extremely well.

[99yam40]

In most cases what we find in carbs is gum and varnish residue left over from old fuel once it evaporates from carbs. The only way to eliminate that is to manually drain all gas out of carbs before storing outboard for any length of time.

Notice that he said manually drain the fuel out of carbs, this requires using the drain plugs not just running till motor dies.
Maybe using the fitting Inducted talked about would help by getting a lot of the fuel out of pump and lines to carbs along with out of the carbs, but would still need to use drains for the last bit of fuel so that it will not leave residue after evaporating.

Good point on where you and the boat are located and where it is stored

[robert graham]

I've always drained my carbs several times a year and especially at lay-up time. On my 90C Yamaha those 10MM brass hex head drain screws are real easy to get at and drain, always put a clean white rag under each carb for draining to catch the gas and look for water or debris. With drain plugs out I pump the primer bulb a few times to "flush" float chambers with fresh fuel. I use the fuel/water separator and Stabil all the time. 1999 motor and carbs never been touched, cleaned or screwed with. The carb draining may be a 10 minute chore, but lots less time/trouble/$$$ than cleaning carbs. Good Luck to you and hope all this is helpful!