Hey All,

Posting the results here because this is where I usually see them. If it should be added to previous build thread instead let me know. Well, here are the results finally. I've had them for a bit as you can see the date but have been putting long hours in so not spending too much time on here. Engine static compression is: #1 9.1:1, #2 9.02:1. #2 was dynoed first which was a little disapointing with final power numbers. When #1 tested higher the shop switched fuel pump, carb, and distributor between #2 and #1 to see if #1 would fall and it didn't. after multiple pulls and long discussions we decided to leave as is.

2 tests on water so far. First time out flooded pretty bad and day was over after being towed in. Took carbs apart and they were dirty. After a good cleaning no more fuel dumping into carb.

Second trial just this past Sunday was better for the most part but still some issues. Get out of the no wake zone and pick it up to 3600rpm and hold for a few min then shut down to take a look in engine bay for any visual issues, saw none. Then decided to WOT but maxxed out at around 4300-4400 rpms, noted. I shut it down at our destination and we spent a few hours on the beach before deciding to run the boat for a while nonstop. took off and cruising at 3800rpms at 43mph (phone gps) until we smelled burning rubber. Shut down and opened hatch to see a hole at top #2 inner exhaust hose. I have exhaust tips a little lower to clear the swim platform and the inner gas tube of the 496 riser flares out, might have to grind out the flare to keep it away from the hose. Ended up limping back to marina on one engine for an hour. Haven't done anything since. Looking to test again on Sat. This time without the lady so it's not a test/fun day and taking all equip and checking/setting time while out on water instead of driveway and pulling plugs for readings. Forgot to mention that when we shut it down after the burnt hose there was a few seconds of "run on" or "dieseling".

Currently, carbs are Merc blue 800cfm that I bought from the classifieds. should be off a Merc blue motor, right, with the staggered jets and 6.5PV in primary? Well, both are 85 jests squared and no power valve. Could my low rpms be due to not enough fuel at WOT? I usually see people here running 92 jets in secondary.

[ATTACH=CONFIG]525620[/ATTACH][ATTACH=CONFIG]525621[/ATTACH]

At work so I'll post more later , but 85 jets squared with no power valve seems light .

The stock 420hp 454 used a 800 holley , with something like 80/90 jets with a 65 power valve in the front .

I bench setup a couple carbs for a buddy two years ago. 454' S with GM rect ports, 236/245 114 LSA cam, single plane intake, nothing crazy. I believe I installed 82 front with 6.5 pv, 92 rear. That was the baseline. I figured it would be a little rich but rather start rich and lean down from there. Upon installing in the boat, afr was around 12.2 at cruise. At wot it was low 11's. A bit rich for a N/A engine, but it was a warm day when we checked it, and he loves holding the throttles pegged for miles and miles. Left it that way. I do need to get with him though as I'd like to jet it down a tad for him.

Are these the same props you had last year, and If so how many rpm did u previously spin them to?

Since I have not PV should I leave the 85 jets in the primary? I will probably get some bigger jets, 90-95 tw swap out this weekend on the secondaries.

Same props. last year the motors were spinning 4600 WOT.

Just noticed the ''dieseling" at shutdown. Yikes. Thats not good.

Put some fuel in it before you hurt em. When you add up the jet diameters and PV channel diameters, of what merc used in your carbs on the 465HP 502, 420HP 454, etc, it comes out to be around .485''. Currently, with the power valve plugged and 85 jets front and rear, you only have an overall diameter of .394" when you add up the jet hole sizes.

This weekend, I'd start with this setup.

Install a 6.5PV in the primary. Leave 85 jets for now.

Install 92 Jets secondary. Leave PV plugged.

I'd be sure you have some sort of fuel PSI gauge, to make sure fuel pressure isnt dropping at wot.Then start pulling some plugs.

What are you running for fuel lines/pumps btw?

[ATTACH=CONFIG]525627[/ATTACH]

Here's a pic of motors installed. I've since added a fuel gauge at the carb on the port side as well. I was going out on Sat alone so may be a difficult to rubber neck at the gauges while at WOT, scary. I'll figure someting out.

Just talked to speed shop and i'll be getting some new gaskets, 6.5PV, and 92 jets tomorrow. Fuel lines are -8 and running the holley 110 mech fuel pumps. On dyno the fuel pumps held good pressure but now seeing the diffeences betwen dyno and actual.

The fact that you burned an exhaust hose also makes me wonder if you were running it lean. Exhaust can get pretty hot when that happens.

Question: Why didn't they get A/F readings during the dyno runs? That would have helped to get you in the ball park. Also, I had them run a steady state test on mine while it was on the dyno for several minutes from 3800 - 4500 RPM's. This revealed that it was leaning out under a fast cruise. Keep in mind that the big 50 cc accelerator pumps on the marine Holley's can mask a lean condition when they are doing a 300 RPM/second dyno pull to WOT. The engine is only running under load for 10-15 seconds when they do this.

OK, I see now that they did BSFC instead. Did they dyno it with headers or your wet exhaust?

They dynoed with their headers. They did do A/F reading I just don't have them in my folder, the shop has them though. That's my thought exactly with the hose burning which is why I'm now trying to figure this out. I will, however, still check the downward angle of the exhaust hose in relation to the flare on the risers. But i'm surprised that it didn't happen to any of the other hoses.

I just got off the phone with shop and letting him know all this and we went over some paperwork and the sh*t gets a little thicker.....my carbs don't have even a provision for the power valves so should I jump up the primary jets to near 90 withe 92 in the secondary?

Ugh....no pv circuitry....wth.

PFFT. Yea, I'd prob go 92 square then...maybe even a tad more to start....SMH.

Can you post up the specifics of the build again for us? Whats the Timing set at again?

Yep, no PV. I got these carbs from here on classifieds, a little disapointed in that decision right now. I'll post the specifics in a bit, currently at work and need to get some stuff turned in.