GoFastSonic

Hey Rob,

I checked the psi at WOT and it stayed steady. the speed does not drop off at WOT anymore and I guess it is normal for the boat to pick up when pumping the $hit out of the throttles and hitting the accelerator pumps?

Thanks

Mike

ezstriper

pumping the throttles at wot won't get any accel shot..you are way past the cams for them to work, need to run wide open on fresh plugs and do a plug test, sounds like the jetting is off...not supercharged are they ? Rob

GoFastSonic

Rob,

no they are not supercharged. I checked the plugs and they looked ok a little gray not white. the new carbs came with 71/83 and I went up to 74/85 which I think should be enough jet. Someone else mentioned jet extensions which makes sense to me, I think I am going to try them?

jmherbert

74/87 sounds like a big gap to me. I would try to keep the primary/secondary size gap around 6-10 jet sizes. The reason primaries have smaller jets than secondaries is most carbs don't have power valves in the secondaries, so the secondaries get larger jets to make up for it. Then again, if they came stock with a 12 size gap...

If it were me, I would try 79/87 and read the plugs. Always better to start rich and work down, then the alternative. Also, check here on how to read plugs:

http://www.4secondsflat.com/Spark_plug_reading.html

RumRunner

This is 100% false you should not gain anything from pumping the throttle at WOT. If that were the case every race boat, drag car, and cup car out there would have the driver (throttle man) pumping the throttle at WOT. This is usually an indication that you are running lean!

Jet extensions should not be required on a offshore boat since they are designed for high G-force loads away from the rear metering block which would happen as you're starting to accelerate, NOT once you're already up at WOT.

You can install a vacuum gauge to check to see how much vacuum the engine is producing at WOT, but with a carburetor of that size with a mild engine if the butterflies are all open it is highly unlikely that you'd be building anywhere near enough vacuum to shut the power valve.

Your tune up on the carburetor is out in left field most Holley carburetors will have about a 6 to 10 number spread (at most) if your only running a Power Valve in one side of the carburetor and haven't made major calibration changes internally.

If you're having to jet up the smaller carburetor that is generally an indication that the fuel system is not keeping up with the demand of the engine. Remember pressure and volume are not the same just because you have the proper amount of pressure doesn't mean the fuel system is keeping up with the demand of your engine.

You should probably flow test your fuel system to make sure it is flowing what it is supposed to, and possibly reset your float levels.

1BIGJIM

iTrader: (1)

There you heard it from the expert.

320es

YOu still haven't said how nasty these smallies are. 1100's are way big for a small block and for most applications a 750 is still to big. Don't listen to whoever is telling you that pumping the throttles will net more speed, they are idiots...Sorry, I am not an expert either.

GoFastSonic

Thanks for all of the advice sounds like we are way of track with our thinking and will try the advice. I installed 2 new fuel pumps and regulators and new fuel line from the pickup's and checked there are no restrictions in the pick ups? Hmmmmm

GoFastSonic

Wellllll they are 350's with 10.5 comp and bow tie heads. Rollers cams with a little bit of lift. Nothing crazy breating thru stainless marine exhaust.

ezstriper

I would run a vacume gauge at this point see what vacume you are running at wot, compair to your power valves, are you running power valves in primary only ? if you are running ft and rear your jetting is to far apart...should be close to sqaure with 2 or no power valves, if only in primary about 8 sizes richer without the valve. jet extensions won't help a bit on a boat like yours...if you checked plugs after any idling you cannot tell much at all....needs to be fresh plugs and a wot run shut right off and pull the plugs then..Rob