F20 startup issue +video

[99yam40]

But no, the seam is not paralell to the carb housing. It is now lower in the end opposite of pivot/needle. I measured it, struck it with a hex-nut on top, then measured again and it had seated down 1 mm (of the 2mm, so half) and I didn't dare to strike it again. My guess is that it moves from temperature, I use the motor even now when we have below freezing. The o-ring allows for the travel when freezing and warming (Only my guess.)

maybe this is how they adjust the float level on these carbs that have none adjustable float tangs

[TownsendsFJR1300]

maybe this is how they adjust the float level on these carbs that have none adjustable float tangs

No way... How would you pull the seat back outwards for an adjustment?

Just the Op being able to move it inwards 1 mm is NOT right...

If fully seated, spec's correct, I'd apply some of the thin red loctite
to seep inbetween the carb body and seat (to keep it from moving).

[99yam40]

Where is this O-Ring?

the seats you posted pics of have o rings, so the op seems to believe his has one also

maybe you are not suppose to push it in too far to start out with.
Yamaha like special tools

[TownsendsFJR1300]

the seats you posted pics of have o rings, so the op seems to believe his has one also

maybe you are not suppose to push it in too far to start out with.
Yamaha like special tools

Panasonic posted some pics / seats with an o-ring on the outside edge (for sealing I assume). It shouldn't change the depth of the seat.

If the Yamaha seat is similar it would explain alot, o-ring failing, allowing movement, but that pic for his engine carb doesn't show that or any re-place-able seat.

Being it is in-deed movable (maybe not available), seems to be the issue.

If it could be removed W/O damaging it would be VERY helpful.

If there's an o-ring-replace it.. If not, loctite that seat in the bore bottomed out..


.

[merc200dalarna]

Since I could see a gap along the outside of the seat, I just assumed there was an o-ring on the seat. As in the seat itself do not fill the bore of the carb body.

Yes, moving it back outward will be difficult, might even be impossible. And since the spare part does not exist, drilling it out is just not an option.

The motor runs fine for now, I have tested it. The only thing noticeable is that the primer bulb is now working as intended again. It gets hard after a few pumps, my guess is that the needle valve and float does its job now. Which leads to the primer bulb getting "stiff" because the needle is now properly closing.

My latest guess is that this carb was issued like this from the factory. Many are produced, and a small procentage has malfunctions.

I'm aware of this carb now, and I plan to own the motor for many years.

[panasonic]

Glad to hear your engine running fine again. It may have been like that from new...but who knows.

You are correct about the primer ball, once the carb bowl is full the needle closes and the bulb becomes hard.

Keep it in the back of your head that the seat may start to migrate out again some time in the future and cause the same problems. If it does this I would try pulling the seat all the way out, clean the seat and bore with brake clean and loctite it back in....if done properly it will not move anymore.

Good luck with the fish.

[rodbolt17]

if you moved the needle seat,buy a carb cause you scrapped that one.
it is a pressed in seat and never ment to move.
the float is fixed and not adjustable.
until backyardigans get aholt of them they work very well.
occasionally I do haave to remove the EPA plug and tweek the A/F screw.

[99yam40]

if you moved the needle seat,buy a carb cause you scrapped that one.
it is a pressed in seat and never ment to move.
the float is fixed and not adjustable.
until backyardigans get aholt of them they work very well.
occasionally I do haave to remove the EPA plug and tweek the A/F screw.

Rod, if you did not read what was going on, he could not tighten the float pin hold down screw without it raising the float.
tapping the seat down 1 MM it now allows the float to operate as it should with that screw tightened up.
have you ever seen a seat move out on a pressed in one?

[rodbolt17]

only when a backyadigan messes with it.
there is a float level spec and it does not say seam level.
if you have moved the seat the carb is mostly scrap aluminium.
most likely it will leak past the seat/body.
I don't know why folks think they need to re engineer anything cause most of it works as designed.
but only if you follow instructions.

[TownsendsFJR1300]

only when a backyadigan messes with it.
there is a float level spec and it does not say seam level.
if you have moved the seat the carb is mostly scrap aluminium.
most likely it will leak past the seat/body.
I don't know why folks think they need to re engineer anything cause most of it works as designed.
but only if you follow instructions.

You need to read the whole thread...

He DIDN'T dink with the float level.

Your leveling BS that did NOT OCCUR by the op and the seat apparently moved on it's own over time..

NOTHING was re-engineered..

Please stop juming to conclusions W/O reading the entire thread. All you posted WAS previously addressed...