carb prob by 1 hung low

[rcsupercat]

hello. i was having idle problems this past summer with my 1996 yamaha c150tlru. sooo i figured I would clean the carbs over the winter... well after opening the bottom carb i found one carb bowl is hangining lower than the other. The manual says to set float height at 16mm, which they both are. my question is how do i determine what height to set the float "drop"? which one is right? or could they both be wrong? ideas?

[zenoahphobic]

Float drop is irrelevant . The float height is just when the needle moved by the float stops in its seat, measured down from the top of the bowl.
It could be possible that the lower hanging float may be leaking and has been distorted by someone to achieve correct fuel height.
Take each float off and see if they actually float well in Gasoline or water.
I can't resist but I like to spend my summer being idle and don't have a problem with it!
I also have a friend called Juan .

[bajakeith]

carbs

float drop is very important,,if/when the float drops so far below the correct range it will bind and get stuck.....almost as important as float height...very,,very old stuff !! and YES 90 percent of fools that call themselves mechanic....don't have the " Touch" or smarts to wipe their ass

[rodbolt17]

please post a link to the page in the 150 manual that gives the float drop spec.
I set the float height with the gasket installed cause that's how it going to be when running and it prevents mix ups when you remove the float to install the gasket.

also look at the + or - on your spec.

[RayBersch]

.... and YES 90 percent of fools that call themselves mechanic....don't have the " Touch" or smarts to wipe their ass

Really? And the world is better for you pointing this out in an email that contradicts the immediately preceding post? I don't think so. Your comment is unnecessary and inappropriate even if your opinion on float position is correct.

Ray

[rcsupercat]

Manual says 16mm + or - .5 mm. They are both right on 16mm.

[rodbolt17]

well it started out with the original poster asking a question about float height yet showing a picture of float drop.

never saw a Yamaha spec for drop.
to check height he would have to invert the carb and repost the picture.
when the picture fails to match the question, that's when I wonder.

[rodbolt17]

as far as 90% of mokaniks.

I spent last week in Kennasaw GA doing an advanced trouble shooting class.
my lab partner was going to take the master tech exam on Friday.
my lab partner had never resealed nor rebuilt a gearcase.
he had never rebuilt a carb on a v4 or 2.6L v6.
he had never worked on any OX66 or HPDI.
he had never seen a V76 carbed motor.
all I had to say as good luck with ya .

[rcsupercat]

Umm. Maybe I wasn't clear.... Both floats sit at 16mm as per the manual. I was wondering if the fact that one float hangs lower than the other could be a problem. That's why I posted the pic... If I posted a pic of the floats "closed" that wouldn't have shown the fact that 1 is hanging lower than the other.

[rodbolt17]

we don't care about the angle of the dangle.
you are trying to set float height CORRECT?

your picture is WRONG for setting float height.
yes it that simple.
to set float height invert the carb, floats on top,you looking down at them.

[boscoe99]

as far as 90% of mokaniks.

I spent last week in Kennasaw GA doing an advanced trouble shooting class.
my lab partner was going to take the master tech exam on Friday.
my lab partner had never resealed nor rebuilt a gearcase.
he had never rebuilt a carb on a v4 or 2.6L v6.
he had never worked on any OX66 or HPDI.
he had never seen a V76 carbed motor.
all I had to say as good luck with ya .

New mechanics are more than likely going to have to learn like most mechanics learned. From the school of hard knocks. On a lot of customer's dimes. And in so doing maybe seeming to be one of the "fools" referred to in a previous post.

With the passage of time it only gets worse as carburetors, EFI two strokes and HPDI two strokes fade into the past. Once the experienced folks are gone, who might have been available to pass some knowledge down, it becomes harder and harder. There is nil Yamaha data that adequately describes the detailed theory of operation for their many many various motors. Pity to the future mekanics.

Might be that the manufacturer's want folks to scrap the old stuff and simply buy new. Which will then come with a learning curve of its own. And the need for more expensive test equipment which in and of itself can be a chore to learn.

[boscoe99]

I agree with Xeno. Float drop is not a consideration. The setting is for float height.

In theory the float is not going to reach the bottom of its drop position given that it will be floating in gasoline. The majority of its life will be at its high position.

If it sticks low then gasoline will flood into the carburetor and cause a running problem. In other words, it will tell you if the valve in stuck open.

[rcsupercat]

we don't care about the angle of the dangle.
you are trying to set float height CORRECT?

your picture is WRONG for setting float height.
yes it that simple.
to set float height invert the carb, floats on top,you looking down at them.

i did turn the carb over to check the float height... and i did measure with gasket in place... then when i turned the carb back over i noticed that one float was hanging lower than the other... thats why i posted my question. i really appreciate all the help... cant help thinking i started a discussion about something other than float height though? anyway... thanx for the help.

[rcsupercat]

BTW... I never claimed to be a Yamaha mechanic. That's why I am asking questions... Not answering them

[TownsendsFJR1300]

BTW... I never claimed to be a Yamaha mechanic. That's why I am asking questions... Not answering them

Its no problem asking, this thread is how most go, on a tangent with diff'ing opinions. Everything on the net is not gospel,

**Just a suggestion, investing in a shop manual for your engine would give the spec's for the float level (and if a spec for drop, that as well). It would also show you how to check / adjust the float level. The level, as noted above, is checked upside down with gravity closing the float. If in doubt the sealing ability of the needle and seat, I've put a Mity vac on the fuel intake port/tube, and see if it can hold a vacuum. It should obviously.

Most carbs, the float level IS checked /measured with the gasket (if equipped vs "o-ring") installed to the carb body.

Last week I worked on a generator (10 HP Tecumseh) that was pouring fuel out the carb intake. Pulled the float bowl (looking for a varnished up bowl/needle/seat etc). I did find a bunch of crap in there BUT the main issue was the FLOAT ITSELF was full of fuel (leaking), dropping open all the time, allowing fuel to flow out... Time for a new float and carb cleaning... That particular float is plastic and is NON-adjustable...