intermittent failure to fill VST

[fairdeal]

keep thinking about oldmako’s “intermittent failure-to-keep-VST-full-at-idle problem”

I think if I had the problem, I would get the engine up on land and study that LP pump performance;

Connect a test lead so I could manually run the pump.
Rig a collection container so I could open the VST drain.

I’d want to get a vacuum reading on the suction side with the pump running continuously.
I’d want a pressure reading on the outlet
I’d plumb some clear tubing into the intake side to see if there’s bubbles when the pump runs.

But if all that checks out under testing - then what?

for an “intermittent” issue,
what can one rig up to monitor pump performance during normal continuous operation ?
a test light in parallel with the pump?
a pressure gauge on the outlet (plumbing on that would be a challenge..)

and his problem is at idle - when the pump is only supposed to run 10 seconds on, 20 off......

[pstephens46]

Could you tap in to the leads with some of Rodbolt's paper clips and meter to verify the timing of pump while idling?

[rodbolt17]

or use your eyeballs.
you can watch the engine filter cup fill and empty with each pump on cycle.
if you suspect the check valve simply pinch off the fuel line below the check valve.
if the problem goes away you know you either have an air leak or a bad check valve.

see how easy this stuff is ???

[oldmako69]

Some good ideas.

Next opportunity I get, I'm going to run some leads to the pump and ensure that it runs as its bolted to the VST. I already tried removing it and testing it at the battery. It was fine. I need to determine if its running as commanded by the ECU. Maybe I can rig a test light so I can see what its doing, or a VM.

I like the eyeball idea better. However, now the engine won't start, so I may have more sinister issues. I pulled the plugs and they all look fine. I was hoping to see them wet with fuel, but they're just caramel brown/black. They look fine. With only 180 hours on them, I suspect that's the first time they've been out of the engines. They were in there incredibly tight. I had to use a cheater on the end of the ratchet to break them free.

I also ordered a MityVac so I can test those inline valves. I've got two old cars with Vacuum systems, so I need one anyway. I doubt those valves are the culprit because I already swapped them from P to S engine. So, pinching the hose probably won't help.

I'll drain the VST as well. Just to be clear, squeezing the primer bulb fills not only the canister containing the first stage filter, it also fills the VST as well, right? It must, otherwise, how would the damn thing start?

I'll also drain it after squeezing the bulb to ensure its full. I recently pulled it apart and changed the filter/screen. It had only a very few small particles of crud.

[fairdeal]

However, now the engine won't start, so I may have more sinister issues.

Crap. Is your name "Job" ?

As Rodbolt has pointed out more than once, not only does the priming bulb fill the VST,
that is the only reason for it to be there.

I think you having swapped the pressure relief valves eliminates it as a problem.
FWIW, here is a video of mine (which works fine) being tested with compressed air

https://vid.me/A0GM

[oldmako69]

I can't squeeze the bulb any harder. Hopefully, when I open the VST drain I will find it empty, and that will help with diagnosis. The engine always started within 2 or 3 seconds of turning the key prior to this. Now, it just spins. This coupled with my previous fuel issue makes me think fuel as opposed to ignition.

I had two issues, number one and primary was the engine quitting at idle. The second, even though it would always start after squeezing the primer bulb, it would only do so if the damn starter actually rotated the engine. Hence my first post on the forum. I was reading everything I could online and found this.

Swapping the relay made no change. A shop verified that the starter was in fine shape. In the 12-15 times I have bumped the starter since I cleaned the buried battery terminals it has engaged. I have a fair degree of confidence that I have resolved the no-crank issue.

Unfortunately, I am headed out of town for a bit and won't get to the boat for a few days. Thanks again for all your ideas and help.

[boscoe99]

Just imagine the (one and only one) high pressure pump being in the boat's fuel tank. Think of all of the problematic crap that would be eliminated from the system? Maybe a pressure transducer on the fuel injection rail to ECU monitor fuel pressure.

Less parts. Less weight. Better performance. Better reliability.

Fuel system problems are the number one problem issue within Yamaha outboard motors. It is no wonder. As parts are added system reliability goes downward.

If I had an older Yamaha four stroke EFI I would do it. If I had a brand new Yamaha four stroke EFI I would do it.

Over on bass boats central there are many Yam two stroke owners that have removed their mechanical lift pumps and installed an electric fuel pump in the boat. Seems to work very well. Very reliable. Installation cost is less than replacing the mechanical lift pumps.

[oldmako69]

I'm all in!

Problem is I don't have the crainial assets to figure it out.

Why exactly, is a 40 dollar fuel pump a 500 dollar fuel pump? I understand that it's a critical piece of gear, but I can go to Advance (or Amazon) and buy hundreds of electric fuel pumps for ten percent of what Yam charges for theirs. Smells bad to me.

How do you remove their lift pump and substitute it with another? Sounds like the ECU might get heartburn if you do.

Luckily for me, I have one engine that is simply sublime. I love it. If I had only a single engine boat, and my port engine were that engine, I think I might sink it in deep water and turn on my epirb, go home and buy a canoe.

[pstephens46]

I'm all in!

Problem is I don't have the crainial assets to figure it out.

Why exactly, is a 40 dollar fuel pump a 500 dollar fuel pump? I understand that it's a critical piece of gear, but I can go to Advance (or Amazon) and buy hundreds of electric fuel pumps for ten percent of what Yam charges for theirs. Smells bad to me.

How do you remove their lift pump and substitute it with another? Sounds like the ECU might get heartburn if you do.

Luckily for me, I have one engine that is simply sublime. I love it. If I had only a single engine boat, and my port engine were that engine, I think I might sink it in deep water and turn on my epirb, go home and buy a canoe.

I like oldmako's sense of humor. Hope he visits often.

[rodbolt17]

it is an electric pump.
you can use about any pump.
it must be USCG/BIA certified and plumbed and wired in configuration to USCG/BIA specs for US market stuff.

other than that the ECU does not know who made the pump.

other than that make sure the current draw of the aftermarket pump does not exceed the 5 amp that Yamaha used.

[oldmako69]

I've been scouring the web and came across this on THT. I don't have any details, but one poster used one of these on his engine. Remarkably, he claims that it even fits in the bracket.

Airtex external fuel pump -

https://www.summitracing.com/parts/atx-e8012s


Other things that I have picked up...

1. The fuel pumps rust internally from the moisture contained within the hygroscopic Ethanol. So, your fancy water / separator only saves you from the water that has gotten into your tank, not the water contained within the ethanol. One guy was tossing pumps like chicklets until he made that discovery. He put a small glass fuel filter downstream from the lift pump and it was collecting crud. He then cut a fairly new (failed) pump open and found rust.

2. The original grey fuel lines from Yamaha are junk and need to be replaced.
Lines that appear supple and fresh on the outside are suffering from a type of delamination internally. I am going to re-plumb my boat engines using this Gates submersible fuel line.

https://www.carid.com/gates/submersi...nkgaAohm8P8HAQ



I am bit amazed that Yamaha hasn't put forth more guidance on this issue with these engines, given the overwhelming amount of information on the interwebs concerning the engines apparent inability to handle even the slightest deficiency with fuel. No matter what you google, if it contains the words 'yamaha', 'f225' 'fuel starvation', 'stalls' RPM', 'crap', 'never again', 'junk', 'horrid', etc etc you'll have enough threads to chase for an entire evening. Add to this list the whole exhaust issue and you're looking at a lot of money spent and time wasted just to keep it running.

As I alluded to earlier, my starboard engine is an absolute joy. It starts instantly, sips fuel at lower power settings and has given me zero issues. Its a wonderful engine. However, it won't turn 5800 at WOT and I have a hard time believing that it was sold in this condition ( being over propped) so I assume that is an injector issue and wonder what's coming down the pike with it. Local shop rebuilds injectors at $35 a pop. That $420 for two engines provided I supply the sweat. Not a huge deal in and of itself for 12 year old engines, but its 5 bills and another day on the water lost to wrenching. I didn't get into boating to become a better mechanic.

If I were buying a new boat today, I doubt that it would have Yamaha's on it. Perhaps a diesel.

[oldmako69]

oldmako

That stall at idle problem after 20 minutes at idle is no big deal (to me) IMO. Just run it until it develops into a serious stall all the time issue, and maybe you'll figure it out. It's not doing any harm to the engine IMO.

If you call a mechanic to the boat and it doesn't stall on him, what does everyone learn here?

Are you getting the same RPMs at WOT on both F225s?

1. I've read that running the engine in this manner will actually damage the fuel pump, since its cooled and lubricated with fuel. And, at 500 bucks a pop, I'd rather not damage that pump. I fear however, that I already have since the last several times I cranked that motor it did not start.

2. No. I bought the boat last last August and have put about 50 hours on it. The first 30 hours of operation neither would turn above about 5200, and now in the last 15 hours or so, the problem engine wont turn above 4400. I'm going to pull and reman the injectors as soon as I get the fuel delivery problem solved.

[oldmako69]

I tried to post some additional info but it keeps getting bounced back awaiting review.

Suffice it to say, I have found a different pump and hose. I'm replacing both. The pump when mine craps out, and the hose as soon as possible. I'm going to replace all the fuel line on both engines. Apparently the fuel pumps are rusting internally and the grey hose's lining is rotting from the ethanol.

[oldmako69]

OK...back from the dead...

To recap, Stbd engine would not idle and then eventually would not start no matter how much I squeezed and how firm that bulb got. The engine would however, run on ether so I knew that spark was not my issue. I surmised that the High PSI pump in the VST had shat the bed. Indeed, when I pulled the old one it was evident that someone prior to me had tried to pry the High PSI pump apart and disassemble it. There were small screwdriver "bend marks" all around its base.

I was in the middle of replacing the T-stats, anodes and getting my injectors cleaned. When I put the whole mess back together, I added a new Low PSI pump...

Yamaha 69J-24410-00,02,-03-00 also Mercury, 888251T02, 888251,T 8825 | eBay

and I added a new High PSI pump....

FUEL PUMP FITS YAMAHA 225 225HP 4 STROKE TURD TXRD TUR 2005 2006 AND LATER | eBay

I turned the key and was rewarded with immediate start and liquid smooth idle. The Hi PSI pump was likely failed and was the reason it would not start. The low PSI pump was likely failing and was the reason it would not idle. I let it idle (on trailer, with engines in the water) for an hour to perform a leak check.
Success?? I'll know over the next 50-100 hours.

But get this, the Port (good engine) was idling along happily and suddenly quit in the exact same manner that the Stbd had been doing all along! Because the cowling was off I could see the fuel level in the primary filter drop. It would drop a half inch and the engine would quit. I had a hell of a time repriming that filter with the NEW Yam squeezebulb. I retraced all my previous steps from tank to racor, and racor to engine. No faults or leaks found.

I swapped fuel supply from one engine to the other and the problem persisted. So, I just ordered another Low PSI lift pump and will install it this weekend.

The bulb thing was bugging me so I took my OLD Moler bulb and hooked it at the very extreme end of the fuel feed immediately in front of the first stage (engine) fuel filter and it had NO trouble pulling fuel through the old Yam bulb and the racor. So, I put the Moler back in.

Lots of crap here, but I think I may have finally gotten this straightened out. Will post up as I run the boat. The engines have only 150 hours though they are 12 years old. The boat sat in a hanger for most of that time unused. Some of my issues are from neglect, and some are from old age.

[99yam40]

yep, if the primer bulb would not push fuel thru the LP pump and into the VST or at least firm up there was something wrong with that bulb or it was sucking air instead of fuel