Learn me some F225 VST venting and what not

[99yam40]

think about it if the VST has no fuel in it what would happen when you powered it up by turning on the key?

[oldmako69]

I have no idea. Its been pointed out to me here, that the squeeze bulbs primary purpose is to fill the first stage filter and VST for initial start. The manual makes no mention of low psi pump operation prior to start that I can find. That's not to say its not in there somewhere, but so far I have not found that information. I work alone, and I am unable to hear my low psi pump operate when I first turn the key. My helm is too far away, and my hearing is that bad.

I bought this thing late last fall and thus far have only put about 50 hours on it. Most of them problematic. My understanding of it is limited, but I am catching up at a feverish pace. Mainly due to my participation and helpful replies that I have gotten here. Sorry if I seem obtuse at this point.

[fairdeal]

how about turning on the key switch

well, yes, but on the F225TXRD that will only supply power TO the LP pump

not ground it to run, so in addition

I believe Rodbolt would stick a paperclip into the back side of the connector

and ground that black wire with a test lead.

I've done that.

[99yam40]

pressure gauge hooked up will tell you lots of things even if the hearing is going south.

Lots of people only use the bulb after changing filters etc to get air out, but some think they do not need to before every start

HP pump running with out fuel to pump,cool, and lube it is not good.

So I see fairdeal says it will not run (lp) at key on.
I guess someone will need to clarify.
I thought it came on for a short time

[pstephens46]

Sounds like excess fuel in vst. It's being dumped into intake. So not running dry?

[99yam40]

I was just trying to address the way to turn on the LP pump

my thoughts on the fuel in intake would be leaking pressure regulator.
still time to use a gauge to check pressures

[panasonic]

I know nothing about this VST problem, but I am getting a great laugh out of oldmako69 posts..hahaha. Should be a comedy writer....give up on the outboard engines...lol

[99yam40]

seems they are talking about a F225 not a F150, and I figured if they were talking about how to get 12 volt power to make it run, the pump would not be mechanically driven,

but you are correct not all fuel injected motors have electrical LP pumps so they depend on someone to pump the primer to fill the VST.
have to wonder if there is something on those that prevent the HP pump from harming itself if there is no fuel to pump in the VST

[boscoe99]

In the Yams with two electric fuel pumps (one low pressure lift pump and one high pressure fuel rail supply pump) the high pressure pump runs for a few seconds when the key is turned on. Once the motor is started the low pressure fuel pump will run for 10 seconds, stop for 20 seconds, runs for 10 seconds etc. as long as the RPM is below 1200. Above 1200 RPM the low pressure pump runs continuously.

It is important to have fully primed the fuel system via the primer bulb before turning the key on. To make sure that the pump in the VST is fully surrounded by and filled with gasoline before it starts to operate. Gasoline cools and lubricates the pump.

[oldmako69]

Bingo. I am fairly certain that this is what killed the HP pump on the other engine. Every time that engine quit, the HP pump ran dry and hot. Eventually the engine would not start. Once that pump was replaced the engine started and ran instantly.

[fairdeal]

have to wonder if there is something on those that prevent the HP pump from harming itself if there is no fuel to pump in the VST

on the F225txrd, the HP pump runs at key on - but only for a few seconds.

It would be interesting to see at what point the ECU re-energizes it - and the LP pump -

I'm guessing as soon as the ECU gets pulser coil output

[99yam40]

So I sounds like the LP pump does not run at all at just key on like Fairdeal said in #21 post.
In that case the OP will need to jumper the pump as was written

[pstephens46]

We are talking about priming the OPs vst, not having to prime every fuel injected
motor every time we start. It should be full of fuel when it is turned off. I have had to prime mine once in five years.

[99yam40]

originally I think we were talking about how to test the LP pump pressure, and I made a comment that was wrong.

But it did eventually bring up the fact that running the HP pump without fuel in the VST is not good for it

[oldmako69]

All this is phantastically pedantic. Really. But it does little to assuage my hyper rich condition.

Why is fuel from my VST being pushed into the "breather" tubes (whatever they are called, the two small hoses on top of the VST that join the crankcase breather hose)?

1. Needle valve not shutting off the flow from the LP pump? I thought that the LP pump did the 10-20 sec jig below 1200 and then switched on full time. Where does any excess fuel go? I have read about the small hoses which redirect the fuel as needed but my understanding is thin.

2. IF the LP pump does run full time (at a constant output) above 1200 then what is the float needle valve doing?

3. I have identical lift pumps. So while it's possible that one pump is overloading the VST, its unlikely given that the other engine runs great.

I'll get this mother spinning yet, clearly just not today.