What fuel pressure for Merc 2.4?

[ONE-A-DAY]

I have twin 1991 carb'd Merc 2.4's on my Eliminator Daytona 22, they are fed by Holley red fuel pumps and I have pressure regulators with gauges. What fuel pressure should I be set at during idle?

Also what hp would these have been from the factory, 225's, 200's, any way to tell based on the serial numbers?

Thanks, Walt

[Badbattery]

I run 3-5psi seats will not hold 7psi. You can look up the serial# on the clamp bracket for hp.

[tlwjkw]

post serial #.... if fat block 2.4 it be xr4 150...... think 200 is gonna be a 2.5 maybe... block style will tell... .. earlier block could be 175/200... '91 is crazy year for merc junk!

[ONE-A-DAY]

Thanks, I looked at the serial number listing and could not figure it out.......the #'s are 0C276008 and 0C276009, the Texas titles say 250hp, but i know that isnt correct.

[tlwjkw]

hi perf. 2.4's... could be carb bridge ports or oval ports.. can't tell on my junk.. either way, probably rated 220 hp.

[ONE-A-DAY]

So no way to tell if they are Bridgeports without opening them up?

hi perf. 2.4's... could be carb bridge ports or oval ports.. can't tell on my junk.. either way, probably rated 220 hp.

[tlwjkw]

head or divider... look on tha welsh plug.. some oval ports have 200 stamped there.. some don't!

[Krazymaan]

So no way to tell if they are Bridgeports without opening them up?

You can shine a flashlight down the spark plug hold and shine it towards the exhaust diverter plate.

The head is very easy to come off and put back on. just torque it back to 30lbs.

Mine is an Mod Vp Oval Port but its from 83' It only has a huge #4 stamped into the welsh plug

[W2F a V-King]

Or use a borescope.

I have one from matco that looks very much like this one. as texasvector mentioned, I am not sure about the HF unit tip size. My matco one does fit OK in Mercury V6 heads, And has a 90 degree mirror attachment that allows for looking sideways.

http://www.harborfreight.com/digital...era-61839.html

or even cheaper and works pretty good...

https://www.amazon.com/Smartphone-En...=usb+borescope

[texasvector]

Or use a borescope
http://www.harborfreight.com/digital...era-61839.html

or even cheaper and works pretty good...

https://www.amazon.com/Smartphone-En...=usb+borescope

not sure harbor freight scope fits in plug hole???

i have one similar to 2nd one......works great....use it all the time

[ONE-A-DAY]

The borescope came in the mail so I took a look, I snapped this pic of my computer while looking at the exhaust ports, this pic is the top of the piston with the port on the bottom of the shot, I am assuming what I am seeing in the middle of the port is the bridge? Sorry for the hokey way of snapping the picture of a picture.

Also, any idea on what these are worth? I have two, both 1990 2.4, serial numbers show as "2.4 mercury racing" both are 130 plus compression in all cylinders, run great, complete drop ons, just took them off this weekend and I will changing over to some fuel injected 260's. I will be listing them for sale soon and was wondering what is a fair price?

Thanks, Walt

[Krazymaan]

To me that just looks like the divider between two ports. The port on the left is intake and the port on the right is exhaust based on one is clean and one is dirty. You need to look to the right more if your looking for a bridge. The bridge crosses the same port and you will be able to see around it. Its the size of a straw.
As for value, it all depends. yours don't have aluminum flywheels, kinda odd. But I just bought the same motor for $1200 with an aluminum flywheel. But some people are selling cheaper and some are trying to get 4k each. I would guess the motor on the left is a real carbureted bridgeport and the one with the painted intake was originally an injected one converted over to carbs.

[W2F a V-King]

Nice motors anyway you look at it...

Something that may help you sell them, do a leak down test and have those results with compression readings, per motor and per cylinder.

The compression tells one story, the leak down gives another story, an idea of how much life is left before "freshening it up" as some call it.

Agree with Krazymaan, rotate the lens more towards the center of the motor to take a better pic of the exhaust port with that piston at BDC.

You already have the compression numbers, so the leak down test can be done easy enough with the power heads on your bench, albeit a better reading if the motors are warm, but that is off the table .... yea..pun intended

GLWS

[ONE-A-DAY]

I called Mercury Vintage Hotline and they are researching the block and serial numbers, promised me a a call back tomorrow, pretty cool service.

[90 5.0]

So what psi fuel pressure LOL?
I was thinking about starting at 4.5-5 does that sound in the neighborhood?