Modification to Fuel Pressure Regulator?

[cichlidfish]

Engine is a 2000, 200 Mercury efi, Serial Number: OT157051

After having my injectors serviced at BrucatoFis I learned that 2 of my fuel injectors are on the lean side, and with the limited funds I have it was recommended that I perform a modification to the fuel pressure regulator that would give me about a 1 psi increase in fuel pressure to compensate for these 2 injectors.

I have the option of sending the regulator off to Jay Smith Racing Engines in Texas to have it done, but he brought up the good point that he couldn't check the pressure after he made the modification. Has anyone on here done this modification before because I got a brief explanation of how to do it, butcan't find any details on exactly how it is done? I'd love to do it myself if possible

[EuropeanAM]

Personally, I wouldn't go this route- as it's a one-way street on the regulator, AND you then are increasing the flow on ALL of your injectors.

Don't know what the current variance is, but I'd encourage you to listen to other options they're offering that are "addressing the problem accurately".

Correct the injector problem and run the engine at it's specified fuel pressure.

New, those injectors are ridiculous. There are some of them out there (used) that would probably be serviceable. I'm fairly confident that Rich offered at least one or two other options (may not be as "cheap"- but they're probably a LOT smarter).

JMHO, of course.

[cichlidfish]

Ok thank you for the advice! I knew I should have saved more money before buying this boat

[Rich Z]

Modification is simple but you need a pressure gauge assembled with a pressure release valve. Air pressure can be used during bench check of the regulator before and after modification. Success rate is 100% on modification if performed correctly and injectors flowing within 2% of each other.

[cichlidfish]

Thank you so much for all the help Rich! I got the engine back together yesterday and I could tell by just the way that it idled in my driveway that it runs much better now. After I do the mod I'll get back and let y'all know how it runs!

[silverbullet02]

You should run it at the lake before you jack with the regulator so you have a baseline.

[cichlidfish]

You should run it at the lake before you jack with the regulator so you have a baseline.

Ya thats what Im hoping on doing now. Unfortunately all the lakes in Colorado are closed and freezing now, but I'm gonna see how it works at out first college tournament at Sam Rayburn and then take it to Jay Smith who lives right next to the lake if I need the mod.

[Rich Z]

Turner, test the fuel pressure with key on only. If its 36psi or lower you will need the mod to the regulator! I do not recommend runimg the motor especially under load with two marginal flowing injectors.

[cichlidfish]

Turner, test the fuel pressure with key on only. If its 36psi or lower you will need the mod to the regulator! I do not recommend runimg the motor especially under load with two marginal flowing injectors.

Just tested it today again and only had 35-36 psi on the key turn, so it looks like ill be doing that. Thanks for all the advice guys and Ill get back in January to let ya'll know how it runs!

[JOE54]

I recommend replacing filter on pump in vst . and heres a lil test for a do it yoselfer . What happens to the psi when vacuum is applied to regulator?????? also what is elev where your at may need a prop change for big SAM. We got air

[cichlidfish]

I recommend replacing filter on pump in vst . and heres a lil test for a do it yoselfer . What happens to the psi when vacuum is applied to regulator?????? also what is elev where your at may need a prop change for big SAM. We got air

When I took the VST apart to clean I made sure that filter was good, and under load the fuel pressure changes very little, if any at all. Haha and I've got my 3 props for the different elevations Its sucks when you could be using your boat anywhere from 10,000 feet in the mountains all the way down to sea level

[JOE54]

smart man indeed sounds like you got it covered ,remember if you bump that press its realy gona be rich at 10,000

[QuickBullet]

Most regulators have a screw on one end applying a set pressure on the diaphram. This screw can be turned IN to increase pressure and out to decrease. BUT.....as stated you need before and after pressure readings to know where you're at!
Also as stated, I wouldn't mess with it! Your problems lay in 2 injectors.....Either replace them or install them in normally rich cyls and keep up with the burn on those 2 cyls until you know you're safe!
Raising the pressure, raises it on all injectors and is not the way to go!
Good Luck!

[revlimiter]

Also as stated, I wouldn't mess with it! Your problems lay in 2 injectors.....Either replace them or install them in normally rich cyls and keep up with the burn on those 2 cyls until you know you're safe!
Raising the pressure, raises it on all injectors and is not the way to go!
Good Luck!

This is what I'm thinking. Every Merc I've ever messed with was plenty rich from the factory. If you have 2 injectors that are "marginal" but still in the accepted range, they will probably be the best running cylinders. Not to be a cynic but it seems like making a mountain out of a molehill on this one. Just think how many of these motors are out there with tons of hours and injectors have never been touched and they're still running great.

[QuickBullet]

This is what I'm thinking. Every Merc I've ever messed with was plenty rich from the factory. If you have 2 injectors that are "marginal" but still in the accepted range, they will probably be the best running cylinders. Not to be a cynic but it seems like making a mountain out of a molehill on this one. Just think how many of these motors are out there with tons of hours and injectors have never been touched and they're still running great.

Exactly!!!
I ran my 260 from 1995 until 2016 and never touched it!
Had Tony go through'em last year and found several borderline. I installed the richer ones in the lean cyls and it's running just fine! Actually I'd be hard pressed to say there was any difference in before and after!