SkiDoc

Thanks for the help Blown Formula.... I have heeded your advice. My boost reference line goes into the port right above the thermostat. I do have my boost guage line T'ed into this port as well...this should not present a problem though should it? Just a question about fuel pressure? My motor is a 96 which calls for 32-34 l.b.s. at idle, why would it be necessary to run baseline 40 l.b.s.? My fuel pressure guage at w.O.T reported right at 60 l.b.s. at didn't really even get to notice the exact boost I was getting(was really concentrating on not hitting a pontoon or a sea doo!)
What is everyones experience about how hard I can run this set up without really cutting back on longevity of the motor. Can I run 4000 on a poker run without hurting things?
I checked plugs which had been installed in the spring. I only got to check two because of time reasons. Yes the impatient wife! The two plugs looked just like they should. I will be more thorough next time! Thanks again for the response as I am on an Island here in Corvette City!

blown formula

#1... if your total pressure is at 60#, you are probably ok. I must ask if that is on a mechanical gauge at the engine or an electrical gauge on dash? Put a mechanical on the engine! non-dampened needle.
#2 ...I would not "T" the boost gauge into the same point as the regulator. There is a dual purpose of the boost line, 1st is for boost & second is to bleed fuel back to the engine intake in case of a diaphragm rupture in the regulator.
#3....My base line of 40# was arrived at because that was the lowest pressure my engine will idle with. Also, Merc said (in a manual somewhere) minimum pressure was 37# at idle. Based on that, I have only an additional 3# of pressure......I'd rather be rich than melted!
#4.... Blown engines are fun, for short periods. Dean Nickerson advised me to limit wot runs to short periods...ex-"if you haven't beat him in a mile, you won't in two miles either!!". Limit wot runs to reasonable short runs. 4000 rpm is not max, but I would not run always at 4000 for a cruise speed.
#5... you cannot get a true reading of plugs using old plugs, they must be new.

Best of luck !!

HPJunkie

KY......,
No pun intended, your boat with a stock 502 in 95' went 78 in a hot boat or powerboat test. So somethings up with what you have. Id check the fuel pressure suggestions the other guys are talking about and read the plugs. Eventually I plan to use the efi setup your running with 15 Lbs of boost with 70# injectors and a stand alone computer with a huge intercooler. I'll need an M-4 procharger so if you hear of anyone selling one of those let me know. My boat ran 90 with 7lbs in the manifold (below the carb) with a round keel bottom keel. I cant wait to try it wit the pad bottom. I was turning a bravo 1 28" at about 5800 rpm. You may think that is high but at 3000 I was going 45 MPH. I am happy with that. The guy that owned the boat before I did ran 93 with a 598" N/A chev 1.36 gear and a 28" bravo prop at 6000 rpm. He then put on a 27 Mirage and went 97 Mph! That was back to back. You can see I am really excited about this program. At 82 MPH was your boat empty, full of gas or what? Keep us posted on your progress. Greg

tomcat

Hey Greg, how's it going?

What did you end up using on the carb, a box or a hat?