Fuel pump or VST filter ?

I have twin 98' - 225 HP Yamaha's EFI. The port engine is not getting fuel.

Trying to avoid another $600 house call, below is the email I sent my mechanic.

We can not get the port engine on reKupperation to start. Thinking it was the EFI fuel filter, I replaced it with a new one, no change. I noticed the small cup would not get any gas (it stayed empty). Thinking it could be the line, I swapped the outputs of the racors from the port to starboard and starboard to port. No change, the small cup still does not get gas. With the lines swapped, I was able to run the starboard engine with no problems. So this eliminates everything leading up to the engines.

Am I looking at replacing the fuel pumps (3) ? or is there some other filter that needs to be replaced ? (VST Filter - injection pump assembly).

Please let me know what you think.

My question is what pulls the gas into that small cup ?

Thanks for your help.

[jb123]

leave hoses on fuel pumps intact but unbolt, pump ball...if fuel comes out of back of lp pumps, diaphrams are bad.

do you hear clicking in vst when key turned on ?

I'll try this weekend when I go down to the boat. Thanks.

JB123, I was thinking through your suggestion and had the following thoughts. Gas does not make it to the small cup where the in-line filter is. I have an electronic pump and when I turn it on it causes pressure in the small cup. When I took the cup off you could hear the release of the pressure, almost like opening a can of soda under pressure. If it were the lp pump and the diaphram, it would not build up this pressure. What are your thoughts ?

[jb123]

small cup....do you mean the motor filter ?

if no gas is getting there you may a restriction on the supply side.

try to run with an aux tank, hose and ball hooked to the motor filter.

JB123,

I could not wait for the weekend, so I went down to the boat to try some of the things you suggested.

Well you know what they so, a bad day fishing is better than a good day at work, the same can't be said about working on your engine.

I was able to run my starboard engine with the line going to my port engine (engine with the issue), so that should rule out an obstrution.

I turned the key to the starboad engine and I could hear the HP pump start. The same did not happen with the port engine. So that's where my problem is. Any ideas how to debug this ? fuse, etc ?

Thanks for being so helpful.

reKupperation

[jb123]

the pump COULD be seized OR im not positive but it could be a issue whereas the pump isnt getting power. Maybe Boats.net will chime in and shed more light.

[boats.net]

I agree with with jb123, there should battery voltage at VST pump when first turn key on, if not check for a blown fuse. Check for battery voltage from red/yellow wire at main relay(number 34 in Yamaha Outboard Parts 1998 S225TXRW ELECTRICAL 3 Diagram
If all ok then replace elect fuel pump.

[jb123]

if you do have voltage, you can comfirm a bad pump, but its a lil more work, by swapping vst from other motor.

if you had a clogged filter or no fuel flow TO vst, it may have damaged pump.

there was a post a while back about momentarily powering hp pump with 24V to free a seized pump.

I found no power to the HP pump (the other engine had). I looked at the fuses and with the exception of the main fuses, I did not find any. I did not find any loose wires. At this point I'm not sure what I'm looking at, a bad relay or if the float switch in the HP pump assembly is cutting the power. Please let me know if you have any thoughts or if I have missed something.

Thanks,

reKupepration.