Learn me some F225 VST venting and what not

[pstephens46]

some.
it is getting very long for a simple vst needle valve leak.

Figured you might shorten it up a bit!

Damn! I see where you already commented above.

[oldmako69]

Pulled the VST. Clean as a whistle. Checked the float operation and needle valve. Clean as a whistle, so, either that was some mighty microscopic crud, or there are other gremlins at work.

Put it all back together and the issue is now resolved.

Both engines run great up to 5800 but I still have persistent stall at idle. Only now its with Engine No. 2, as opposed to No. 1. It starts instantly, idles smooth as glass. I let it idle at the dock and it went 20 mins before it crapped out. Pumped bulb, restarted instantly and shoved off. It quit within about 5 mins. Squeeze - restart - quit in about 3 mins. Back to dock.

Lo PSI pump appears to be properly filling the first stage filter and the engine is dying WITH fuel evident in the first stage filter. Hi PSI screen spotless.

What a PITA.

[pstephens46]

So the VST is running out of gas. I have lost track. Did you dig into this VST too? Back and forth between engines....
It's a wonder you haven't checked yourself into the hospital yet. Hey, I do know a good ENT surgeon in Norfolk. Has a brand new 50ft Hunter. But I digress.

Maybe Rodbolt can clear this up quickly...

[oldmako69]

He suggested that the VST needle valve was the issue. I have not confirmed that, because it was sparkling clean and free as I just posted. But it IS running now without flooding the intake. But not without stalling.

This is the engine which never gave me a lick of trouble. Now, its quitting and the other is running great.

[pstephens46]

Wouldn't be nice if there was some video camera you could dunk in a fuel tank to have a look? With a light. Maybe fairdeal has some pics of how to tee into the lp line somewhere. Tee in a pressure gauge that is.

[TownsendsFJR1300]

Could you have an air leak prior to the under cowl fuel filter?

Perhaps hook up a portable tank (direct to the filter) and see if that helps?

[panasonic]

Wouldn't be nice if there was some video camera you could dunk in a fuel tank to have a look? With a light. Maybe fairdeal has some pics of how to tee into the lp line somewhere. Tee in a pressure gauge that is.

Gopro with a explosion proof light tie wrapped to it...but you might blow up.

I don't know what would happen...

I know they dunk them in diesel tanks to have a look around, but diesel is hard to light with a match, but gas go boom!!!

Judge yourself accordingly.

[pstephens46]

I'd be glad to watch from a distance and view the video a little later.

Interesting concept though.

[99yam40]

as long as there is not much O2 it will not go boom.
heard of running a hose from running motors exhaust pipe into tank to limit O2

[rodbolt17]

you fixed the needle leak issue.
like I said the ONLY way to inject fuel into the air box is by overfilling the VST.
the only way the VST overfills is the needle failed to seal.

now we cannot fill the vst .
if by pumping the primer we can now fill it I would suspect an air leak between the primer and the lift pump or a faulty lift pump bypass relief valve.

[oldmako69]

<<"I would suspect an air leak between the primer and the lift pump or a faulty lift pump bypass relief valve">>

OK. I can use a mighty vac and / or a fuel pressure gauge to test all the fuel lines. My questions,

Which is the lift pump bypass relief valve? The one inline between the lo psi pump outlet and the top of the VST? Or, all of these inline valves identical in both function and trip pressure? If so, I can swap L to R in an attempt to isolate the faulty valve. They're over 100 bucks a toss, so I don't want to just keep hosing my wallet if I can sensibly avoid it.

Can I use the Mighty-vac to test this as well?

Thanks.

I suspect that the majority of my problems are from the lack of use of the boat, and ethanol. I have not opened up the tank because of his claim that the boat was left stone dry, and that because all of the fuel I have sampled to date has been completely clean and free from any sign of separation, sediment or discoloration.

Since most of the fuel delivery issues so far have been with the other engine, I suspect that its fair to assume that I overlooked something on this one. I will repeat the steps which I took to get the other one up and running.

[fairdeal]

Which is the lift pump bypass relief valve? The one inline between the lo psi pump outlet and the top of the VST? Or, all of these inline valves identical in both function and trip pressure? If so, I can swap L to R in an attempt to isolate the faulty valve.

yes - the one zip-tied to the LP pump housing

you can certainly swap it from engine to engine - they should be the same part.

(There are similar but different valves, in other places / engines)

IMO the best test for a suction side air leak is plumbing in/swapping out a length of clear tubing for the black

bubbles will be visible

[oldmako69]

Thanks. Easy. Will do upon my return from exile.

As far as the swap, that was the very first thing that I did way back when I was having issues with the other engine. Unfortunately, this provided no change. While its possible, I suspect that those valves are OK.

But, stuff happens so I will get Cro Mag with all the fuel delivery plumbing on Eng No 2 now.