2005 Yamaha F25

[Copper_John]

Hi
I'm new to this forum and of course looking for some advice. I have a 2005 f25 Yamaha outboard that I have been running for the last 6 years without any major issues. My annual maintenance is new plugs oil changes (upper and lower), fuel filter and water separator filter. With the exception of a flat spot when accelerating it has run like a top.
This spring after my maintenance ritual(this year I put in a finer water separator filter) I had a tough time starting it and at low speeds it would idle rough and occasionally stall. I ran a gallon of gas (93 octane) mixed with a generous amount of Sea Foam carb cleaner. for a while I thought it did the trick but on my last fishing trip running the motor at low speed(*****ing) was lower than usual to the point of making little headway. Still it accelerated fine and ran perfectly above minimum speed.
First sorry for the long post. I tried not to leave anything out.
Where should I start carburetor or fuel pump?
thanks

[TownsendsFJR1300]

Sounds like the carb is partially clogged.

As you have higher RPM's, the fuel pump is probably fine.

I'd pull the carb, all the jets, and clean spotless. Just spraying carb cleaner W/O visually inspecting don't count.


Carb is pretty basic:

http://www.boats.net/parts/search/Ya...TOR/parts.html

*Storing W/O draining the carb (drain plug on float bowl) allows fuel to remain and clog jets, especially ethanol fuel...

And BTW, there's NEVER too much information, it all helps!

.

[Copper_John]

Thanks Scott
I'll give it a try. First I'll order up some gaskets.

[99yam40]

o rings gaskets usually can be reused.
Myself I would take apart and clean, inspect and buy only what is needed

[pstephens46]

I assume you installed a 2 micron fuel filter in place of a 10 micron?

And then the problems started?

Is it possible that filter is causing issues or you introduced an air leak somehow?

[TownsendsFJR1300]

I assume you installed a 2 micron fuel filter in place of a 10 micron?

And then the problems started?

Is it possible that filter is causing issues or you introduced an air leak somehow?

I have yet to see a 2 micron fuel filter, if they even exist for a transom filter or under cowl filter..

But re-reading, what IS a "finer fuel filter"? Splain please?

[99yam40]

yep they are around
2 Micron Fuel Filter | eBay

[Copper_John]

I have yet to see a 2 micron fuel filter, if they even exist for a transom filter or under cowl filter..

But re-reading, what IS a "finer fuel filter"? Splain please?

I had originally used a 21 micron filter. This year I went with a 10 micron filter.

[Jason2tpa]

I ran a gallon of gas (93 octane) mixed with a generous amount of Sea Foam carb cleaner.

Who am I to say higher octane can increase your engines performance? So I rely on research to provide me with the information. If you're interested in learning everything about fuel, follow the link below. Referring to your statement about adding a higher octane fuel, see the quote below.

Automotive Gasoline FAQ

6.13 Can higher octane fuels give me more power?

Not if you are already using the proper octane fuel. The engine will be already operating at optimum settings, and a higher octane should have no effect on the management system. Your driveability and fuel economy will remain the same. The higher octane fuel costs more, so you are just throwing money away. If you are already using a fuel with an octane rating slightly below the optimum, then using a higher octane fuel will cause the engine management system to move to the optimum settings, possibly resulting in both increased power and improved fuel economy. You may be able to change octanes between seasons ( reduce octane in winter ) to obtain the most cost-effective fuel without loss of driveability.

Once you have identified the fuel that keeps the engine at optimum settings, there is no advantage in moving to an even higher octane fuel. The manufacturer's recommendation is conservative, so you may be able to carefully reduce the fuel octane. The penalty for getting it badly wrong, and not realising that you have, could be expensive engine damage."

[Jason2tpa]

I ran a gallon of gas (93 octane) mixed with a generous amount of Sea Foam carb cleaner.

Who am I to say higher octane can increase your engines performance? So I rely on research to provide me with the information. If you're interested in learning everything about fuel, follow the link below. Referring to your statement about adding a higher octane fuel, see the quote below.

Automotive Gasoline FAQ

6.13 Can higher octane fuels give me more power?

Not if you are already using the proper octane fuel. The engine will be already operating at optimum settings, and a higher octane should have no effect on the management system. Your driveability and fuel economy will remain the same. The higher octane fuel costs more, so you are just throwing money away. If you are already using a fuel with an octane rating slightly below the optimum, then using a higher octane fuel will cause the engine management system to move to the optimum settings, possibly resulting in both increased power and improved fuel economy. You may be able to change octanes between seasons ( reduce octane in winter ) to obtain the most cost-effective fuel without loss of driveability.

Once you have identified the fuel that keeps the engine at optimum settings, there is no advantage in moving to an even higher octane fuel. The manufacturer's recommendation is conservative, so you may be able to carefully reduce the fuel octane. The penalty for getting it badly wrong, and not realising that you have, could be expensive engine damage."

[TownsendsFJR1300]

Plus 1 ^^^.

The copy and paste says it all..

[Copper_John]

When I bout the engine used 6 yrs ago he gave me the owners manual which recommended the higher octane fuel. I am thinking part of my problem is I have never drained the carb bowl just ran it dry every fall after my last fishing trip. I'm sure some crud got left behind. Next sunny day I'll pull the carburetor for a cleaning.

[TownsendsFJR1300]

When I bout the engine used 6 yrs ago he gave me the owners manual which recommended the higher octane fuel. I am thinking part of my problem is I have never drained the carb bowl just ran it dry every fall after my last fishing trip. I'm sure some crud got left behind. Next sunny day I'll pull the carburetor for a cleaning.

You hit the nail on the head (in bold ^^).

Even thou it's run dry, just a little bit of fuel remains in the bowl. Best to pull the bowl drain plugs(s) out, maybe a spritz of air, but let the fuel evaporate out of there.

Both my BIL's 10HP B&S generator and friends 10 HP B&S generator, both carbs clogged after being run dry (no stabilizer), (no drain plug, pull the float bowl ONLY, etc).

Make sure you actually pull the jets for a visual, it doesn't take much to clog em...

[Copper_John]

Well I pulled the carburetor apart. I found a slight coating of crud. Cleaned it up pulled the jetssoaked them awhile I could see daylight through them. Put it back together but being one to snatch defeat out of the jaws of victory I broke the ceramic block assembly on top of the carburetor. I'm pissed! My new question is how do I determine which one it is. The parts list show a couple. Please show some pity for this stupid soul.

[TownsendsFJR1300]

Not quite sure what : " ceramic block assembly" is..?


What is the EXACT MODEL of your engine? Should be a plate with "F25 ***" (on the engine, near where the engine tilts).

Clicking on upper right corned of this page, in RED, states "purchase yamaha parts" .

Can you please post the carb LINK for your engine and what part # broke?


(BTW, glad you found some crap in there)