Check out the Innovate Motorsports web sight. Their air fuel meter will allow you to not only do your jetting but to dial in your entire fuel curve by adjusting your high and low speed air bleeds. I don't sell them I just bought 1 and like it.
http://www.innovatemotorsports.com

Ok guys, I.m confused here. In the driveway, they nearly fouled the plugs out with #86's after 2 mins at 2000 rpm. So I put the 80's in the primary and down to the lake we went. Ran it 2 minutes at about 3,000, pulled them off, pulled the plug white white white. So in teh drive way with no load means nothing when it comes to find teh right jets on teh primary side. Don't understand why but obvious they run a whole lot different in the water with a load.

Immediately installed the #88's in the primaries,left #92's in secondaries. New plug in each number #7 cylinder, ran them them at 2,000 fora bout 2 minutes and pulled the plugs again. No sign of change in color of the electrodes, porclines dull dull white, maybe beginning to go gray. Reinstalled plugs and ran them up to about 3800 rpm for about three minutes, secondaries actually begin to open at 3,200 rpm. Pulled #7 plug in each one, plugs look like they are going gray on porcline. The base (Metal edge) of the plug appears dry black.

My confusion is that I believe I can go to 90's on the primaries but when i got back to the dock after idling for about 3 minutes, I pulled the same plugs and they were black black black. Look like they would foul running like that. Is there another adjustment I should be making to keep them running to and from the dock?

you said the carb had 70 pri and 80in the sec. which make the carb a750 -4779. so you should start with 75pri. and a5.0 power valve and 84 and no powervalve in the sec. make shore the fule line to the motor and filter are at least 3/8 id. total timmingshoulbe 34 dregeesby 4000 rpm and then fine tune from their I DUE A LOT ENGINE PACKAGES WITH 750 HOLLEYS AND THAT IS A GOOD STARTING POINT

Thanks for hanging in there on this one formulaz583. Your last comments along with CMS Racing are interesting.

First, yes these are twin 454's in a 1984 36' Coyote, early Sonic as I understand it. They have been responding (plug readings) the same to the changes we have been making. Since formulaz583 mentioned the PV early on in this thread, I noticed I have 6.5 PV at least on the primary side, haven't been back into the secondaries since then but will see what PV I find in there today, if any and will let you guys know.

Timing is still concerning me. Here's the deal. The indicator on the block runs up to about 16 degrees BTDC. These engines seem to start and run good at about 18 degrees at least at about a 900 rpm idle. I managed to sit in front (face about 12" from the belts, scary) of one of those running about 3000 rpm (in the driveway) and watched the timing retard but of course there's nothing for me to read. If I used the indicator increments as a guide and had to guess based on how far the timing moved, I would guess about 32degrees but again that's just a guess. How do you guys check total timing under these circumstances? And are you checking this under load or is the "driveway" ok for this check?

Now about that PV. CMS is saying I need to a 4.5 PV with 75's in the primary and 84's in the secondaries. I haven't a clue. Formulaz583 what are your thoughts, you had mentioned these PV previously. What do you think about the combination CMS is suggesting? I can order the PV (doubt the local part house has them) Monday and I already have jets in the 70 range coming in.

Thanks again guys, I'll get back to you today on the secondary PV situation.

Forgot one thing that I haven't mentioned, I am running Champion RV15YC4 spark plugs. Thanks for the links on plugs formulaz583, makes me think the plugs are the right ones, just need to work through these other issues. The carbon cleaned up as soon as I ran them at mid range or higher settings, simply loaded-up when idling.

no the are not the . you need a R5673-7 ngk or champion v63c or a equilvent to the plugs extended tip plugs are no good in a marine engine they can glow and cause pre ingition call me at my shop 410 335 2226 CMS Racing Engines from 9.00am/4.30pm if you have any questions concerning this matter

try a MR42T OR MR41T AC PLUG IF THAT IS EASY TO FIND IN YOUR AREA. Rember the jetting recommendation I gave you is for a marine or auto 750 dp. I have dynoed many 454 and 502 in this power range and I have found if you go more than 6 numbers higher in jet you have to due major work on the mettering blocks and air bleeds to make the carb work properly . the jetting recommendation should give you a good exhaut temp and good air fule ratio. give me the list # on the carb and some more details on the motor and what altiude you boat at and I can help you get close. sounds like you are getting the timming set 32. to 34. total . set under no load is the easyest to due .you can measure the balancer and mark off 32. or 34. degrese or if it is a gen 5 or 6 the balancer is all ready marked and you dont need a advance type timming light.

no I said the jetting would fit either the marine 750 or the automotive carb on the same engine the only diferance in the carbs is the j tubes and the 850 carb is going to use more jet than a 750 . if you run 93 squared in a 750 air fule ratio would be 6.1 or so. you have to compare apples to apples.

Thanks CMS Racing for the time on the phone today. Thought I'd provide my cam information and see what you thought. They are:

Comp Cams
Part #11-000-5
Engine CB 396/454
Grind # CB 6084/6002 FT114
S/N: 2 6226 & 2 6227
Intake Exhaust
Valve adjustment: .018 .020
Gross Valve lift: .533 .562
Duration at .016 tappet lift: 268 282

Open Close
Valve Timing at .050
Int. 5 BTDC 45 ABOC
Exh. 56 BBDC 0 ATDC

Specs. are for cam installed at 110 intake center line

Intake Exhaust
Duration at .050 230 237
Lobe Lift .3140 .3310
Lobe Separation 114.0

Not sure if all that's good, bad or indifferent. All we did was get Comp to match a Crane cam supposedly made for Mercury Offshore Racing years ago for about 10 of these engines that were shipped to Miami, at least that's all Mercury Offshore Racing could tell me about the original Crane cam we found in the engines when I bought it. Since we could get Crane to run new one's (anytime soon anyway) we provided the information to Comp and they came up with these cams and solid lifters. If you have any new thoughts, please call me at 800- 727-1468, or post a reply. I'm usually in the office from about 9:00 to 5:00 CDT (New Orleans).

Thanks again for the insight. Trying to round up those MR 43T plugs you and Formulaz583 suggestioned along with a 5.0 PV. Will install this stuff, and some #76 in the primaries (I have those) and #86 in the secondaries (got those too), get the total time right (for sure) then take it to the lake get some vacuum and plug readings and see what I end up with with that set-up. Probably be the weekend before I make the lake. Thanks again.

Quick update. Installed AC MR43T (#10 under the new numbering system). The best I could come up with on the jets were some #76's for the primary and I put #86's in the secondaries; better a bit rich CMS than lean, the pocket can't take anymore lean problems this year.

Degreed the balancer up to 34 degrees. Based on previous timing of 18Degree at 900 rpm, I was getting about 28 degrees total at 3,000 rpm, no load, driveway. Adjusted timing till I got 34 degrees total timing; again, seems to occur at about 3000 rpm, no load, driveway.

The PV's are 6.5 in both the primary and secondaries. Here's the twist this week. Placed a vacuum gage on the carb (vacuum port just under the primary bowl, front of engine). At 1000 rpm idle, it read 18. As I advanced the throttle, the vacuum went to 22. I thought as the throttles went up, the vacuum would move towards the 6.5 where the PV would eventually open.?.? Based on yours (formulaz583) being 12 at idle and 4 when going on plane, I confused again. Would appreciate a more advise about this. Thanks, Al