1995 c150tlru needle valve seat

[rcsupercat]

hello again. i am in the middle of cleaning/rebuilding the carbs on my 1996 150hp. one of the needle valve seats seems to be leaking. i put a vacuum gauge on to check and it cant hold air. all 5 others seal fine. if i put my finger over the top of the assembly it still leaks. thats why i think it is the seat not the needle. i looked around online and i cant seem to find a replacement seat. yamaha doesnt include it in their carb rebuild kit either. 2 questions... how do i remove and install new seat? and who sells them? thanks in advance for the help.

[rcsupercat]

Oops. It's 1996 not 1995.

[TownsendsFJR1300]

Looking at the parts fisch:

1996 C150TLRU Yamaha Outboard CARBURETOR Diagram and Parts

Its not replaceable. The needle itself usually wears out way before the seat does.

The needle itself usually gets indented (is the softer of the two) and wears out first.

**Did you try putting another float and needle on the "bad" carb, hold it upside down letting gravity close the valve. You should be able to hold a vacuum doing that (pulling at where the fuel intake line is). Make sure the other side of the two barrel carb is sealed off (so there's no leakage there)

Please update what you find...

[rcsupercat]

Looking at the parts fisch:

1996 C150TLRU Yamaha Outboard CARBURETOR Diagram and Parts

Its not replaceable. The needle itself usually wears out way before the seat does.

The needle itself usually gets indented (is the softer of the two) and wears out first.

**Did you try putting another float and needle on the "bad" carb, hold it upside down letting gravity close the valve. You should be able to hold a vacuum doing that (pulling at where the fuel intake line is). Make sure the other side of the two barrel carb is sealed off (so there's no leakage there)

Please update what you find...

i changed the needles and floats around and it still leaks. i just vacuum tested again and i noticed if i push down on the floats (pretty hard) it will seal. soooo i guess its not the seats... i am waiting for the carb rebuild kits to arrive in the mail. i hope new needles will solve the problem. So you are saying the carbs are junk if the seat goes bad? *** that is just silly (imo).
in the pic the top needle seems to be a little worn. hope replacement is the cure for the motor stalling when going into neutral issue. cant wait for spring!

[TownsendsFJR1300]

I can see in your pic's there's a little wear not on the seat but on the side guides of the needle. Of course, too much slop isn't going to help sealing.

I suspect the new needles will probably fix your problem, especially with nice new rubber tips that'll seal better than hardened, old ones...

As noted, I'm looking at the parts fisch and don't see any "seats" available separately.

I know its hard to see down there, but do you see anything unusual in that one hole AND, is there visibly a separate seat or a brass seat pushed into the carb?

[rcsupercat]

I can see in your pic's there's a little wear not on the seat but on the side guides of the needle. Of course, too much slop isn't going to help sealing.

I suspect the new needles will probably fix your problem, especially with nice new rubber tips that'll seal better than hardened, old ones...

As noted, I'm looking at the parts fisch and don't see any "seats" available separately.

I know its hard to see down there, but do you see anything unusual in that one hole AND, is there visibly a separate seat or a brass seat pushed into the carb?

it looks clean around the needle seat. the brass in the center looks ok. by that i mean it doesnt looked pushed down on any of the carbs. when the carb rebuild kits arrive i will install new needles and see if that fixes the problem. your time is appreciated. thanks for the help.
*not to beat a dead horse... but it seems odd that a worn seat would mean that a carb goes into the scrap heap. weird.*

[rodbolt17]

you tell me how rubber is going to wear out brass.

you explain that and I will tell you how to polish the seat.

[rcsupercat]

you tell me how rubber is going to wear out brass.

you explain that and I will tell you how to polish the seat.

maybe water got into the carb. and tarnished the brass?

[rodbolt17]

then polish it.
I use fine grit valve lapping compound and Q tips.
cut the Q tip in two.
dip the cotton ball in lapping compound.
chuck it in a drill.
polish the seat.
then CLEAN CLEAN CLEAN it to remove any lapping compound.

[rcsupercat]

then polish it.
I use fine grit valve lapping compound and Q tips.
cut the Q tip in two.
dip the cotton ball in lapping compound.
chuck it in a drill.
polish the seat.
then CLEAN CLEAN CLEAN it to remove any lapping compound.

That is a great idea! Thanks much for the info!

[99yam40]

Seats are usually damaged by someone trying to clean them with objects they should not be shoving down in them.
keep hard wires and other things out of brass seats and jets.
Even damaging the shape of fuel jets messes up the flow rates designed from what I have read, so drilling out a jet is not the same as buying a larger jet

[rcsupercat]

Got my carb rebuild kit yesterday. After polishing the needle valve seats and installing new floats and needles, all seems to be well. Thank for the help. It is appreciated.