Fuel Pressure regulators

[IRBBoater]

Does the exterior rust on a regulator affect the operation of the regulator?

[cpostis]

Does the exterior rust on a regulator affect the operation of the regulator?

IRB,
please provide complete model # of your motor.

Don't have any idea of what regulator you are talking about. Can you post a picture as well?

[Sequoiha]

Eventually it will rust thru. Spray it with fluid film to slow it down, if you do replace it spray the new one down.

[boscoe99]

Light/medium corrosion on a fuel pressure regulator should not affect the regulator output. Which is easy enough to test.

As Sequoiha notes, clean the corrosion off as best you can and then apply some type of corrosion prevention product. Monitor the regulator in the future as part of your normal maintenance program, along with the rest of the components on the motor that can and will corrode. Particularly make sure there are no leaks under the cowl. Moreso if operating in salt water. Yamaha had some brand new motors that got completely ruined with thermostat gaskets failed and salt water sprayed on the motor. Some of that salt water got sucked down the intake and got to the valves. A two month old motor looked like it was a forty year old motor on the inside.

[cpostis]

Light/medium corrosion on a fuel pressure regulator should not affect the regulator output. Which is easy enough to test.

As Sequoiha notes, clean the corrosion off as best you can and then apply some type of corrosion prevention product. Monitor the regulator in the future as part of your normal maintenance program, along with the rest of the components on the motor that can and will corrode. Particularly make sure there are no leaks under the cowl. Moreso if operating in salt water. Yamaha had some brand new motors that got completely ruined with thermostat gaskets failed and salt water sprayed on the motor. Some of that salt water got sucked down the intake and got to the valves. A two month old motor looked like it was a forty year old motor on the inside.

Is the fuel pressure regulator IRB talking about one on top of a VST, or another regulator I am not familiar with?

[boscoe99]

All I believe (based on the title) is that it is a fuel pressure regulator. I am assuming that it is the Yamaha type that has a plated metal surface that is now corroding. Some are on the VST and some are in other places.

There are only a gazillion different types of pressure regulators.

"We have answered so many questions for so long now with so little information that we can now answer all questions with no information at all."

[pstephens46]

Think he done be gone...

[IRBBoater]

Fuel Pressure Regulator

Sorry, I am new to all of this forum and trying to figure it out as I go. Hopefully with all of your help it won't be so painful.
I am the new owner of this boat. The boat, a Pro Sports Pro Kat and engines are 2004, engines are 115 4 strokes TXRC's. The boat is used in salt water only.
Both engine's start and run but are RPM limiting, one at 3800 the other at 4500. During the sea trial two months ago, both engines ran to 5500 and 5600 RPM.
So now it begins, Both fuel pressure regulators are rusty and located on the fuel rail, which I understand is a common problem if left untreated, which these are. My mechanic is saying that both regulators need to be replaced based on the visual rust. I am having difficulty understanding how both non electrical parts failed at the same time because of rust? You all know the cost of these regulators and so I am cautious at spending that kind of money only to find out I still have the same problem, but have nice new shinny expensive fuel pressure regulators.

[rodbolt17]

my guess would be the VST filters are clogged.
test the fuel rail pressure.
I have seen a few regulators rust through and leak fuel.

[boscoe99]

It is a simple matter of installing a pressure gauge and seeing if the regulators are working or not.

Now they may be working well now but depending upon the extent of the rust it might be a good idea to remove and replace them. Just a judgement call. It is easy for a mechanic to spend a customer's money. But it might be that the mechanic is looking out for your best interest.

Both regulators failing at the same time is not normal.

What do the fuel filters look like?

[IRBBoater]

Fuel Pressure Regulator

The regulators are rusty but show no signs of leakage. The left tank racor had approx 1/4 inch of water in the collector bowl, the right tank racor had no water. Both engine fuel filters were clean.

[pstephens46]

So as said above, check fuel pressures. Use the VST drains to dump contents to check for water there. Water here, water there.....ethanol?

[99yam40]

fuel leaks under the cowling are not a good thing, try to keep that from happening.

water in filter means water in the tank.
how much is in the tank?
being the pick up tubes do not sit all the way on the bottom. you have some free water sloshing around down there

[IRBBoater]

Latest update, I have replaced both racor filters, both engine filter bowl filters, cleaned both inline filters. Cleaned both VST filters, replaced both engine driven fuel pumps and both regulators (due to rusty condition). Cleaned injectors on the Port eng. Fuel pressure at idle is 38 port eng and 39 stbd eng. Fuel pressure is the same with engines in gear under a slight load. Port and STBD engine prior to all of this work was Port 3800 RPM now at 4800 and STBD 4500 RPM now at 5100. Still off the target of 5500 RPM. No computer faults noted, Engines run smooth with no hesitation during acceleration. Any suggestions on where I look next?

[99yam40]

what is rail pressure when RPM is at max not a slight load?

Is that not where you are having a problem