F225 changed VST and she ALMOST starts

[cmitchell2]

2002 F225 550 hours changed VST filter, put new rubber damper in, cleaned out vst tank, changed F shaped filter, tested low pressure pump, tested high pressure pump ( they both sing nicely when 12 volts applied) then put all back together. When turn key to on position I can hear low pump pumping. The hose on top of VST that goes to injectors was spraying gas because clamp was loose (I got a new clamp) so i believe high pressure pump still working after being put back in vst tank. I started her up on ear muffs and she ran at idle for 2-3 min. I hand squeezed the bulb til good and firm. Dropper her in the water 5 minutes later and she won't start. She ALMOST starts but wont. She sounds flooded and gas trickles from black plastic silencer. What am I missing here?????? Thanks for any help

[rodbolt17]

the low pressure pump wont run at key on.

it cycles 10 seconds on 20 seconds off below 1200 RPM.

if the lift pump relief valve leaks you get a few min run time and the VST is out of gas.

always try to understand what is SUPPOSED to happen VS what IS happening.

and just because a pump is running doesn't mean fuel is flowing at the correct pressure.

its why I bill 85/hr.
I typically spend 1500 a year going to schools and another 12 to 15 hundred buying and replacing tools.
my 9 yr old snap on rail pressure tester is wobbly now.
soon I gotta spend more jack to replace it.
another 296 bucks.

[arctic 1]

rodbolt sounds almost like mine

[cmitchell2]

image.jpg


Should there be a rubber stopper in the round hole next to the Phillips screw? There is a needle valve there I believe.

[rodbolt17]

should be but they either fall out or get left out overtime.
its common and wont hurt diddly squat.
all that valve is for is to allow air in when you crack the VST drain valve.
the VST vent is that valve at the upper port side of the air box.

[cmitchell2]

rodbolt17, thanks for trying to help me. I appreciate that you have invested lots of $$ and time to be a master mechanic but I am in a little time crunch here to get one of my engines running. The marina can't get to my boat for 3 weeks and here in Pensacola the Blue Angels are flying this weekend. Friday is kids day on my boat and if I had known I would have just left the engine alone and delt with not being able to get full rpms from it. Now for some reason after changing the vst filter and following the step by step from Andy at Sim Yamaha (which was awesome) something has happened where this engine won't start now. It ran for 3 min on the rack and when I put her in she wouldn't start.? It seems like it is flooded and I smell gas. Should I check spark plugs??****** I just remembered and this could be very important***** that when i went to take off battery cables I forgot to turn off battery switch and positive
cable hit the motor it made a big spark. I turned off switch as fast as I could. The motor did start after that but maybe I blew something?? Maybe a fuse went bad after that?? I'll go to boat and check this morning.

Thanks again for any help.

[cmitchell2]

I have a small update. Went to boat and checked all fuse were good. Decided to try and crank on the work rack and she started right up and ran smoothly at idle for 2 min. I shut her off and tried to start again and she will not start. I'm thinking its a computer thing keeping it from starting after things have circulated and/or warmed a little. I read about sensor behind oil filter that you can take out and clean that it sometimes gives false info. I unplugged sensor and put it back on bit got the same no start. Any ideas ??

[TownsendsFJR1300]

Will the under cowl Yamaha fuel filter stay full if you let the engine idle for more than 2 minutes (WITHOUT re-priming the squeeze bulb) or does it run dry/empty?

You may have to run it for longer than that to ascertain the pump is actually pulling fuel..


From Rodbolts Post #2, it sounds like the pump (at least to me), is NOT keeping the VST full of fuel.

[cmitchell2]

The fuel filter under the cowl stays full yes. Thanks

[cmitchell2]

Update # 2. 5 spark plugs fouled pretty bad. Changed them and fires right up. I shut her down when I noticed fuel coming from black hose that connects to the top of the silencers. It has what I think is a vacuum line coming from the top of the vst tank. What is going on here? I'll try to post a pic

[TownsendsFJR1300]

Parts 26 and 27

2002 F225TXRA Yamaha Outboard INTAKE Diagram and Parts

Blowing up that pic above, that hose shouldn't be resting on the flywheel, is that how you found it?

[cmitchell2]

No I took off silencer so I could look at vst and fuel lines. I assume some overflow gas goes up that tube but it was way too much.

[cmitchell2]

I did a fuel pressure test and got a constant 45 lbs so pump is pumping good.

[TownsendsFJR1300]

Well, no ones posting yet but it shouldn't be leaking fuel down there, it appears to just vent fumes.

Something is leaking fuel into there, broken line, something definitly not correct for it to be dumping fuel thru there...

The VST, I'm thinking is the closest thing thats got fuel pumping to it or out of it. Is the vent tied into the air intake at all, overflowing and flooding the engine?

Maybe some back tracking while its running to see how that fuel is getting there.. As much is there, shouldn't be hard to find..

(yes, I'm guesstamating)

And good luck..