1989 Mercruiser 5.0LX fuel pressure

[mudweiser]

We installed a Edlebrock carb and the motor ran great. All of the sudden, it developed a wide open bog. If i let off the throttle it comes back to good power. Leaning towards a bad Holley fuel pressure regulator. No matter how i adjust the screw on the regulator i can't get above 4lbs or fp on the gauge mounted inline near the carb. This number has ben at idle. I have not had a chance to get the hull on the water. How much fuel pressure do i need a wot for a stock mercruiser 5.0lx? Do i even need a f.p regulator running from the mechaincal fuel pump? I replaced the fuel pump 2 years ago, but maybe it's bad. Dunno. The motor runs great except for wide open.

 

[mkast]

Re: 1989 Mercruiser 5.0LX fuel pressure

Why is there a fuel pressure regulator installed?
http://forums.iboats.com/showthread.php?t=295070

 

[mudweiser]

Re: 1989 Mercruiser 5.0LX fuel pressure

When i installed the carb, i also installed the FP regulator which was recommended by Edelbrock. I thought twice about it, but the bling factor and the fancy stainless steel braided line had me sold. I know it looks sweet, but i have to question if it is my problem. The boat ran great after the install on one trip. Which was also my last time on the water before having a problem. The next trip out it had a WOT bog. Not wide open out of the hole, but only once the boat was on plane and allowed to run it's full rpm's. I'm propped right and not over-reving. I could easily remove it, but i'd rather trouble shoot it now that it's in. I can't get more then 4 LBS at idle or even more then that when the throttle is applied. Shouldn't that motor run fine on 4lbs? I know i question that when the gauge shows 4lbs is it actually 4lbs? But i can't get it too adjust to have more or less then that.