2006 Optimax float sticking

[scottsdale]

I have a 2006 Optimax 225, serial # 1B378539 that the float is sticking closed every so often. I have replaced the fuel pumps recently, rebuilt mechanical pump, installed new needle valve, and ran new Mercury fuel line. When the float sticks closed you can not pump any fuel into vapor separator with primer bulb. Fuel filter side of vapor separator has fuel when you open drain port and can pump fuel through fuel filter side with primer bulb. When you open fuel pump side drain port, there is no fuel and primer bulb is tight. You can bump the the side of vapor canister and float unsticks and will fill with fuel again and run. The float looks good, not bent, or twisted. If float was bad it would not shut fuel off as it hangs downward. Any other issues that would cause this? Could it be vapor looking some how? Is there issue with mechanical vacuum pump? Not for sure of what to do next. It may run for 3 days, all day on water and then just all of sudden stick.

[Savage]

Check the vent on the VST canister for blockage.

[JOE54]

inlet valve seat may need a lil polishing

[EuropeanAM]

inlet valve seat may need a lil polishing

+1... OR the loop portion of the float, the float pin, or even the TANG of the float may be damaged.

Any of these items can cause the float to "stick".

NOTE: It's very important that the float not close with any more pressure than is exerted by inverting the VST cap. If you bump or bind the float during assembly, the needle may develop a ring at the seat that can cause the needle to stick (often required 5x magnification or greater to see it).

[scottsdale]

I was going to replace the needle seat when I change needle valve but they don't have a part # for it in mercury so I guess it is not serviceable? you would think by design that it would be impossible for it to stick since gravity and that compartment going dry once it sticks. It is odd that it just does it every so often.

[EuropeanAM]

One often overlooked area is the tang of the float. If it develops a "divot" where the needle contacts, it can cause the needle to bind/stick intermittently also.

When you have it out again- look at the top of the float. If you see a line mark (perpendicular to the length of the float) on the top of the float it has been jammed during assembly at some point.

There's a boss in the top cover that will "leave it's mark" on the top of the float (I've even seen one where it punched 3/8" deep into the float).

[scottsdale]

The top of the float does have a line in it. Thought that was just the way it was made because I couldn’t really see anything that it could come in contact with under normal conditions. So if it has a indented line it has been bent before?

[scottsdale]

The top of the float does have a line indented in it but I thought this was normal because I didn't see anything that it would hit under normal operating conditions. Does this indented line mean that at some point it was bent and bottomed out and now would need to be replaced? The float looks straight when it seats the needle valve.

[EuropeanAM]

Can't tell you "when" that happened, just that the float was jammed into the seat at some point during assembly forcing the float up into the top cap of the VST.

That indent or line shouldn't be there, but in and of itself, is just a "clue". If you don't recall seeing it from the beginning, probably wise to get a float and a needle to replace it with (now).

HP fuel pump sleeve (also).

[BBallFisherman]

Just out of curiosity, what were your symptoms during a running condition that lead you to this find? Or was it something you happened to dig into after the change in priming?

TIA

[scottsdale]

I have just replaced the needle valve and has been ran one time. I would like to replace the needle seat but can’t find a part number for it. Is it a replaceable part? Is it pressed into cover or screw in?

[EuropeanAM]

Seat is not a replaceable component.

[scottsdale]

Okay thanks, would this come with new cover kit, Mercury # 889317T 1 ?

[EuropeanAM]

Yes, the seat is a portion of the cover kit.

[scottsdale]

I was having fuel issues, engine would die. I may have misdiagnosed it in beginning as a bad fuel pump because there was no fuel pressure. No fuel pressure because no fuel to fuel pump. Was able to check fuel on each side of vapor separator and no fuel on fuel pump side, so it was not transferring fuel to fuel pump side.Just did checking to see where fuel was present.