No good answers on carb problems

[sherwin]

After a frustrating season of carb breakdowns, where I had to disassemble the carb 4 times and
clean the jets, I am still no further along in solving the problem. I'm being told that the problem stems from small 4 stroke outboards like
my T9.9 having fine jet openings that are subject
to blockages, that my carb with a float bowl is more likely to produce gunk, to problems with the
newer gasolines. All nice theories, but no firm
answers. I have taken steps like adding Stabil and Mercury Quickclean for carbs to my gas tank
and still I have these problems. I'm told to drain my carbs or run out all the gas between usages (what a pain). Is this just my engine that
is the problem, or is this just poor design by the
Yamaha people. I never had these problems with my two previous 2 stroke engines (Seagull and Chrysler). Is this something Yamaha wants to hush
up to avoid a major recall of these smaller 4 stroke engines? I have no confindence in taking this engine out for a cruise. My last short sail
required a tow when the engine stopped running just outside my port entrance.

[Ken]

sherwin,
Yamaha came out with a service bulletin a few months ago recommending the addition of a 10 micron water separating fuel filter to combat the ill effects of ethanol blended gas - if you don't have one already, you need to get one installed.
Good luck [img]smile.gif[/img] ,
Ken K

[Operaman]

Ken is correct. Get a Racor 10 micron water seperator filter. It can only help.

[slim]

what is your problem?

[oddnumb]

check the fuel pump. my f-100 did the same, all of the junk was coming out of the fuel pump - after the filters.

[sherwin]

To answer all the kind replies:

As far as a water filter separator, what would be the relationship between blocked up jets and water in my gas system? The only way I can get the engine working again is to run a fine wire through the two carb jets.

The fuel pump is a possibility. However, although this engine is a 2002, it has very few running hours on it, so far. Maybe about 50 hours. Would one expect the fuel pump to go bad, so quickly?

One thing I might try doing is replacing the fuel
line from the tank to the engine. I am still using my original fuel hose from my previous engine. because it can connect to my old Chrysler
6 gallon tank. The 6 gallon tank that came with the Yamaha is just a tad too big to fit through the opening of my outside locker. I have inspected the tank and cleaned it, and there are no indications that is the problem. The hose is still flexible, but maybe needs replacing. I am
trying to find a quick disconect fitting to match
up my Yamaha hose to the Chrysler tank. I may wind up cutting off the end of the old hose and connecting it to a filter first. Speaking of filters, I am using a common 40 micron filter made
by Tempo in line with the tank. Marine stores near me (mostly West), only carry tempo filters
of 40 microns. People tell me I should be using
a 10 micron filter, but I can't find any. I haven't inspected the filter on the engine itself,
which I think is a 10 micron. I don't believe I have a fuel starvation problem, but maybe I should
swap that out too. Problem is that there are no
Yamaha parts suppliers in the lower Great Lakes/
Chicago area, and I dislike buying parts unseen.

I still feel Yamaha has not addressed this problem
adequately.

[sherwin]

Is there someplace I can view this Service Bulletin on the 10 micron filter for water separtion? I still don't understand the connection between removing water from the gas and
the gasohol interaction producing blockages in my
carbs.

Is Yamaha selling their own filter, or just recommending that type of filter? Where can on buy
this Racor filter?

[jb123]

they only thing not addressed is the care of fuel to your motor.

[jonp]

Hi Sherwin,

The 10 micron filter are not easy to find. Surprisingly boater world and west marine did not have these... I ordered a few from www.defender.com They are about $10 each. I think quite a bit less than Yamaha version. Boats.net (the sponser of this site)I am sure would also have these as well...

Good luck

Jon

[Bluebird]

You might have screwed the pooch with the wire.
Just an observation but nobody recomends using anything but carb clean(deep creep) or blowin them out from the inside with air. You may have permenently reset your jet size by accident.

[slim]

it really sounds like your still getting trash into the carb, which a filter would help or your just not getting it all the trash out to start with.

[sherwin]

I don't think I did any damage to my carb jets. The engine runs fine, once I clean them out. I used a very fine wire, not a crowbar.

The fuel itself is probably not a factor since it was purchased in different gas stations that looked like they had a large turnover and were not small independents. The fuel was treated with Stabil and in one case Sea Foam was added, in another Mercury Quick Clean was added.

I'm still trying to find out how to get this Yamaha Service Bulletin on adding a filter to remove water. Is it available online any where?

Thanks for all the replies.

[MrBigStuff]

You're fixated on the water separating aspect. It's the 10 micron filtering capability that comes along with the filter that will help to eliminate these fine particulates that are clogging your jets that you want.

There's alot of reports of newer blends of gasoline containing ethanol that is degrading certain materials (tanks, lines, carb parts, etc) and gunking up motors. You say you're using an old fuel line from anothr application. Perhaps this line is not compatible with the gasoline and it's gunking up your carb jets. A fine filter just prior to the carbs would block these particulates but also consider that the surface area of the filter must be large enough to allow for extended use. You don't want to be swapping in filters every couple of hours. Ultimately, you want to find and remove the source. Anyway, some things to consider...