Not to beat a dead horse but s.b also known as Scott /CFM has pretty much explained this to you on the other thread in fairly good detail. You might not Know this but he IS a expert at airflow and owns a company that does cnc development work on flow technology/manifold work, carb spacers etc and he is in the know. If you listened to 1/2 of what he has to offer you might be enlightened, Smitty[/QUOTE]

Smitty, are the calculators irrelevant or not? This is were I have not got a real answer. If so, I will choose the biggest carb And then learn to tune so it will work. Some of us are novices and need a starting point.

In your reference to listening to only 1/2 of the so called advise, 1/2of it was complaining on why I was sticking to the Cfm formula. At one point, one post stated running Dom 1050 on 350 or 383 motors. I then asked if I could run an 850cfm and was told that no I should not run it due to it being a big block designed carb? I was not paying attention to part numbers?? Can I run a 600 Cfm on a 540cu??

I beg to differ on the detail provided.

I am not running a 383 Whipple charged 600 HP power plant.

What carb would you recommend? I personally am going for the Holley 600 DP.

Smitty, are the calculators irrelevant or not? This is were I have not got a real answer. If so, I will choose the biggest carb And then learn to tune so it will work. Some of us are novices and need a starting point.

In your reference to listening to only 1/2 of the so called advise, 1/2of it was complaining on why I was sticking to the Cfm formula. At one point, one post stated running Dom 1050 on 350 or 383 motors. I then asked if I could run an 850cfm and was told that no I should not run it due to it being a big block designed carb? I was not paying attention to part numbers?? Can I run a 600 Cfm on a 540cu??

I beg to differ on the detail provided.

I am not running a 383 Whipple charged 600 HP power plant.

What carb would you recommend? I personally am going for the Holley 600 DP.[/QUOTE]

Sorry for getting this thread off track, I will find your other thread and repost, Smitty

See go-fast.com, you're making it too hard.

Ray, thank you for the input and an intake is on the list for sure. But I haven't started researching then just yet since I just sent out the tail to CMI for the O2 bung to be welded on. I want to get the engine running correctly for how it is set up right now. There are some stalling while idling and shifting issues that I think are going hand and hand with the excessive fuel pressure. Once this is ironed out the intake and throttle body will be next with having the ECM re-flashed to compensate.

You are correct, I did pay a lot of money for this project and it is leaving me with a disappointed feeling right now. Hopefully I can get to the power and performance I was hopping for.

Hopefully next weekend I will be able to start getting some O2 readings.

Thanks again for the input and solidifying what I was feeling.

"A Kenetic energy equation has nothing to do with the power required to overcome drag. Except for applying Bernoulli's theorem which exchanges potential and kinetic energy of a fluid for pressure, which equates back to lift and drag forces."

See, now talking about lift, drag and Bernoulli makes sense to me.

We had the boat out four times now and I am starting to figure things out a little bit.

My extended steering lines that I had built for the e-box additions are all leaking hydraulic fluid and it appears the ID of the lines and the ID of the fittings are different. They are telling me that they replaced the lines with the exact same thing that I gave them. Hell, at this point this is an easy fit but like everything else with this project more money for things that should have been done right from the beginning.

Now to the real meat and potatoes. I had an O2 bung welded on a tail and was able to get some O2 reading with fuel pressure.

I put a fuel pressure gage and O2 gage on it and it confirms it is rich at idle. I made some adjustments to get the idle O2 reading to 13.5 and I could hear a distinctly better idle but I could not leave it there, because once it had a load it quickly became too lean giving me an O2 reading of 14.7-15.5. I readjusted the fuel pressure to give me an O2 reading with a load 12.5-12.9. But the fuel pressure now is VERY high. 58-62psi. But this now gives me an idle O2 of 11.8-12.0. Also, there seems to be a lean spot at the 4500RPM point, it gives me 13.1-13.2 while operating at that RPM.

(The fuel pressure gauge is not calibrated but brand new)

The temp for the day I took these readings was in the mid 70s at 800' MSL.

Here are some other RPMs and readings....

Idle (700RPM) 11.8-12.0 w/ 58-62psi
1500RPM 10.8-11.0 w/ 56-60psi
4500RPM 13.1-13.2 w/ 58psi
WOT 5400RPM 12.6-12.9 w/58psi

Thank you VERY much for reading and any assistance.

sounds like there is no way around it, you need to have your ecu specifically tuned for your set-up. I never did hear-do you have the merc 555 or was it converted to the mefi 4a/b. I hear not many places can tune a 555, a few yearsago I remember hearing that Crockett was converting these to mefi4's, that is a step backwards as far as things go but at least anyone could climb in your boat and tune it properly. With accurate afr readings though you might be able to send your ecu to Whipple or Raylar or maybe even Crockett has a 555 program these days, I haven't talked to him in a long time, Smitty

Smitty, so my findings and numbers are not good for prime performance? And could be the reason for some of the problems?

It has already been specifically tuned and it is the ECM that I believe it can only be tuned by three people. What I am worried about is not having it on the engine when it was/is re-flashed, having to send it out without knowing what was done or changed and knowing it fixed the problem.

Thank you for the reply!

Your ecu may have been specifically tuned for your combination but looking at your numbers it could really be straightened out from some on the water tuning. If thats not possible you could make a real detailed chart of where your afr's are all the way up and down the rpm band at different loads. You then send your ecu back to your tuner to make some adjustments and test againuntil you are pretty close. Back in the 90's this was the normal routine for tuning the mefi 1-3 equipped boats, I think AZSM was the only one who could do it at first, then a few guys were doing it (Crockett/Whipple) and now every shop has a tuning program. Unfortunately with your "555" you are going to work with the few who has it, call them and make detailed afr notes, it can be done mail order, it just takes time and patience, Smitty

Thank you again for the help.

I can make a detailed chart of the afr's. Question, what increments would be best? Also when you say "different loads" are you talking about different trim positions?

I have the Innovate LM-2 "Basic Kit" because I did not think there was a way to record RPMs with our engine like you could with the OBD-II. Is there a way I can get the RPM info on the Innovate LM-2?

I am going to repost our discussion, there are probably some not reading because they may think it is a ***** fest.