Yamaha 150 TXRC carb float question

[Psalm 99]

Dunked floats in water (floated nicely). Figured gas may have permeated into floats causing problems so weighed each float. All weighed exactly 70 grams so floats appear to be sound. Engine running well now with no gas leakage. Will get a few spare needle valves though. $13+ seems pretty steep for the valves but I guess its cheap compared to a lot of other things that could have been wrong. Thanks again for the help - Al

[zenoahphobic]

metal seats do not get damaged by rubber tip needles with a small amount of force or even a large amount.
Needle tip possible, but not the seat.

trash in the seat, corrosion, or damage by someone poking something hard through it are the main causes of seat problems.

Yes,sorry meant the rubber tip

[Nautical]

Blow into the inlet at the same time moving the float up and down. In the valve closed position (Float up) you should not be able to blow . You sure the floats are floating ??

[99yam40]

Inversion can exert more force and damage the seats slightly.

metal seats do not get damaged by rubber tip needles with a small amount of force or even a large amount.
Needle tip possible, but not the seat.

trash in the seat, corrosion, or damage by someone poking something hard through it are the main causes of seat problems.

[TownsendsFJR1300]

Did not even think of that!! Damn. That's Right THE Oil Gets INJECTED After So I Could Run Right Off THE Bulb With REG gas.
I also already dumped 3 cans of sea foam in tank

The Seafoam certainly won't hurt anything and diluted in 90 gallons, its effects will be minimal. I use Seafoam mostly for storing engines(put in the top end), but Seafoam isn't NEARLY as effective as Ringfree.


My 01 Four Runner (16,000 miles) started getting a higher than normal idle( the fuel system was NEVER serviced). Put in several doses of RF, 2-3X the recommended amount, cleared it up over some time(couple of weeks slow improvement. Now, it idles 600 in gear, about 650 with A/C on. Before it was about 2-300 RPM's higher. NO other servicing, period...

I run it in EVERY GAS ENGINE I own and it goes in every customers machine I fix (easily 90% fuel issues). Haven't pulled any of my carbs apart since using it. Original VST filter, injectors, etc in my F150 OB as well(never pulled/cleaned, etc)

[TownsendsFJR1300]

Psalm be careful using the upside down and float weight to seat the needle.
The maximum force in a design is that of the weight of the fuel displaced by the float floating.
A small therefore exerts a very small force before shutting the valve. Inversion can exert more force and damage the seats slightly.

I respectfully disagree.

Most carb flat adjustments are done just as directed by the shop manual, upside down, gravity only.

It takes a bit of intentional force to change the float level tangs.

Even if you get slightly more pressure on the needle seat with the float closing with fluid, the better!

That little bit (if even true) is minimal and designed that way.

With that said, generally, if I have a potential issue with a leaky valve, I'll hook up a small auxiliary tank to the carb (off the engine). Leave the float bowl off, then flip the carb to the correct position. Then open and close the float gently. You'll see if its holding or not.

Needles and seats do wear over time. IMO, if in doubt, just change them out, adjust with gasket on, (test if need be) and be done with it.

[dbranco00]

Did not even think of that!! Damn. That's Right THE Oil Gets INJECTED After So I Could Run Right Off THE Bulb With REG gas.
I also already dumped 3 cans of sea foam in tank

[TownsendsFJR1300]

The issue running 2 times the ring fire is that there is 90 gallons of fuel in the tank....

Hook up a 6 gallon tank temporarily...

[dbranco00]

The issue running 2 times the ring fire is that there is 90 gallons of fuel in the tank....

[TownsendsFJR1300]

Where are the pilot jets or the idle jets located? Can you take a picture?
IS this correct that there are 2 idle jets per carb??

And where are they located, was told to take them out and spray some sea foam in them let sit overnight and start up next day. Should 90% of the time clean them out. The boat has great performance after 1300 rpms, just wont stay running at idle...

Click on the link I posted in post #21. There's a picture there.. The slow jets are parts #10, and yes one jet per venturi (3, two barrel carbs). Simply pull them all out and use carb cleaner on them. Once you can see thru them, their good.

The regular use of Yamaha's "RINGFREE" is MUCH,MUCH BETTER than Seafoam :

https://www.shopyamaha.com/product/d...?b=Search&d=34

**If your reluctant to pull the carbs apart, running 2x the recommended amount of Ringfree may clean out the jets(depending on how clogged they are). It will take some time running if going this route.

Run RF regularly (with fuel stabilizer) and you won't be cleaning carbs anymore...


Sorry for the hijack...

[zenoahphobic]

Psalm be careful using the upside down and float weight to seat the needle.
The maximum force in a design is that of the weight of the fuel displaced by the float floating.
A small therefore exerts a very small force before shutting the valve. Inversion can exert more force and damage the seats slightly.

[dbranco00]

Where are the pilot jets or the idle jets located? Can you take a picture?
IS this correct that there are 2 idle jets per carb??

And where are they located, was told to take them out and spray some sea foam in them let sit overnight and start up next day. Should 90% of the time clean them out. The boat has great performance after 1300 rpms, just wont stay running at idle...

Ordered a manual but it take 10 days to get here. OR can you take a picture of your manual if you have one..

Thanks
Dan

[Psalm 99]

Engine back together (again)

Could probably take carbs off and replace in my sleep now as I've had to do it so many times. If I had kept the float set with the gaskets in place, there would have been significantly more force applied to the needle valves and life would have been easier. Setting to the factory specs required really good cleaning of the needles and orifices to get a proper seal. Engine now is running strong, idling well with less vibration and I was able to loosen the idle adjustment screw noticeably to achieve the same idle RPM's (about 750). Possibly running leaner with better fuel economy (time will tell). Still concerned about the needle valve(s) leaking with time, however though with the carb removed I pressurized the seal with gravity (floats upside-down) and Mityvac'ed the fuel intake tube up to 15 psig with no leakage. Leaving assembled overnight also may have helped by slightly swelling the needle point with gas. Holds ok with priming bulb stiff but I'll order new needles just in case. Although I just visually inspected the idle jets, you access them thru the brass screws at the carb base. You would need to remove the carb(s) to do this. Thanks to all for the good advice - Al

[boscoe99]

What's wrong with the setting to his manual (without gasket) after he fixes the leaking needle and seat?

That is what I would do.

As much as I am critical of crappy Yamaha data, in this case I believe the SM is correct. There are too many other SM's that provide the same information. That is, the float height is checked from the bottom of the carburetor body and not from a gasket.

I suspect that in lieu of installing a new float valve (and thoroughly cleaning the valve seat) many just change the float height to make the problem go away. Unfortunately, this is just a band aid approach. Problem is, while a leaking seat problem may be solved the fuel level in the bowl will be affected which can cause other issues.

I would install new valves, after making sure the seat is clean, and set the float height per the SM. I suspect the problem will go away. If not, maybe change the float height as necessary to solve the problem but not to the extent that measuring from a gasket would change it.

[TownsendsFJR1300]

I have the same engine and its runs great at all speeds except idle...

Is there anyway to pull the jet out and clean and re install without pulling the carbs off all together?

And if so can someone please send me in the right direction and where that idle jet is located on the carb?

I have done motorcycle carbs but they are always under the float and it had to be taken apart..

Thanks
Dan

Dan, If you could start your own thread would be better. It tends to confuse issues between two different engines on the same thread.

Here's your carb parts fisch; 2004 150TXRC Yamaha Outboard CARBURETOR Diagram and Parts

Jet locations are on there and yes, you do have to pull the carbs... No different than the bike, and probably easier to get to once off.. Jet #10 is your slow speed jet. I'd pull all the jets while there and VISUALLY INSPECT at the least..