Click on his screen name. Depending on how you are looking at SCJB ( app or website) you can direct message him. It should send an email notification if he has one setup.
The last time he logged in was Nov 25,2018.


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Thanks.  I’ve sent him direct messages but haven’t gotten a reply.  I’m assuming based on his login history he’s never received them.   So I was hoping someone knew him or had other contact info.   


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Is the boat still for sale and available for showing this weekend?

If the OP doesn't want to change the carb and keeps his engine cover, it might be a good idea, for safety reasons, to replace the bowl vent tubes with the correct marine tubes. This would help prevent filling the engine compartment with gas in case a float/needle and seat decides to stick.

I'm guessing that most of my engine is not marine legal as there aren't a lot of marine parts available for a Hemi, carbs are.

Bob

I don’t have an engine cover, it’s an open engine. 


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Take all these suggestions with a grain of salt... It's really difficult to troubleshoot something from a computer... But that don't mean we don't try like hell...LOL


There is a vacuum line on the carburetor base. Where does that go? I will assume to the distributor? Take that hose off and throw it in the trash.........


Those flame arrestors are a bit restrictive, may consider an upgrade down the road (likely works fine for what your doing right now). Just worth mentioning.

For that 3310 carburetor. The stock configuration is as follows.  List; 3310-2,750CFM (Front main jet)72, (Rear metering)plate 134-21, (Power Valve) 6.5, (Series)4160

There are a couple things you can do to this carburetor to improve how well it works... One at a time, in order....

Main jets, I would bump it to a 74 jet...
Leave the metering alone, but drop the Power Valve down to a 4.5"
The secondary spring needs to be replaced to the lightest Yellow spring from Holley, this is under the cover on the secondary dashpot.

See if you can locate a 1"- four hole carburetor spacer that fits that carb, use the thin base gaskets...

It is imperative that the timing get dialed in, but it will be all for not if the distributor is worn or the vacuum is hooked up. To check for loosness, remove the cap/coil using the four spring loaded screws. inspect these parts as they come off. I can totally explain why the vacuum can't be hooked up if you wish...

Now grab the rotor and check for side to side movement or slop, there should be virtually none. Now rotate the rotor to the right and left, it should rotate in one direction springing back in one direction. it should move about 15° fairly freely (about 1/2hour if it was a clock). Again no hose on the small dashpot...


GT

Ok, I’m playing catch-up reading through the recommendations and I’m starting to get a feel for how the carb works.  Correct me if I’m wrong, but it seems like your part recommendations are to get more fuel into the primaries, and the vacuum secondaries to open sooner with the softer spring.  Both make sense to me, but I wonder if I’ll get less engine efficiency and more fuel burn with that setup.  Just thinking out loud. 

I’m not understanding why disconnecting the vacuum line helps the situation.  If you don’t mind explaining it or explained it somewhere else I’d appreciate learning more about it. 


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The list number for that carburetor is under the flame arrestor on the air horn of the choke.
I feel the tach is faulty, you can verify it with a cheapo dwell tach tool. Those Medallion tachometers were prone to vibration and had return spring issues. With that said, if your distributor is worn out and jumping around, it will read high and cause a high rpm running issue.

The vacuum advance SHOULD NOT be hooked to anything, if it is, disconnect the hose and plug or cap the port on the carburetor.

You say you set the timing, but you didn't say to what. Sorry, but I really need to know. Idle timing is completely worthless unless you know how much mechanical advance is built into the distributor (and that it actually works). You are going to want the timing at above 2,000 to be at around 34°BTDC

 On the carburetor, there are NUMEROUS things that need done to make a vacuum secondary carburetor work... Not difficult or expensive to do. With a list number I can get you stupid close from here in my kitchen... 


To shorten up you having to go check everything, grab another tach (Portable test instrument or otherwise) and give it a quick water test.

I would bet an ice cold beer that the carburetor is set up incorrectly...And that the distributor is worn out. Very common issue. (loose shaft causing eronneous trigger problem).


Hope this points you in the right direction..

GT

Thank you for all of the help.  Next time I go out I'm going to hook up another portable tach and use that to verify the correct numbers and then start running down the troubleshooting list you gave me. 

The Holley carb list number is 3310-2. 

I'll post pictures.   

Based on the diagrams I found online it looks like the vacuum advance is already plugged.  The distributor feels solidly attached, not sure how else to troubleshoot that thing. 

The basics...


What brand tach?

What type of ignition system?

How hacked is the wiring?

How well does it run?



Basics. Some early style tachometers need adapter modules to work with some ignition systems.

Many tachometers have a rotary style switch on the back to change from 4,6 and 8 cylinders. On rare occasions it can have a pole switch, this is for an outboard and they use the alternator to read RPM. Ensure the switch is on the 8 cylinder mode... The thing is, if it was set for 6 cylinder, 4,200 RPM would read about 5,500 RPM. However, 3,700 would put you in the right range. So if the engine is pulling an honest 3700 RPM, the tach would read 4800 and the speed you mentioned is totally plausible at that rpm....

Moving forward, that would put you in the low 200 HP range, I'm not convinced, but if your secondaries on the carburetor were plugged with crap or inoperative, again, quite plausible... What carburetor are we talking about? A list number would be the bomb....

The last tidbit before we start getting feedback would be have you checked the basics?

Compression test. (always a good idea to get a baseline BEFORE stuff blows up).

Ignition timing and operation of the mechanical advance (if so equipped) Does the distributor have a vacuum advance (shouldn't).

Throttle linkage, does it open the carburetor to 100%?

If you get some information back, there is a good chance the problem will be staring you in the face. Since we know your pump is solid, we can remove that from the equation...

In all honesty, I would have gone with an "A" cut impeller. With your HP, it's going to be tough to get where you need to be without another 75 or so HP...JMO.


GT

Here’s what I’m working with:

Sorry about all the carb pictures, not sure where the list # is.

Not knowing what you are working with, I would gestimate closer to 4,200-4,400 RPM

GT

AA heritage impeller.  325HP BBC. 

I've started a new thread to help me get this figured out.  (http://www.socaljetboats.com/engine-mechanical-electrical/tach-reading-high-where-to-start-troubleshooting/msg337871/#msg337871)  I'd be happy to hear any advice on where to start on getting this fixed. 

Unless that thing is built to the hilt, calling bullshit on the 4,800RPM. That would require 450 or so HP, If I had a 450 HP 19' boat that only went 48 mph I would be pissed..... Your tach is wrong and the tune is way off...JMO Not being a douche, just trying to help...



GT

Thanks for the input.  The tach is gonna be my next project then. 


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Just for reference, our 69 tahiti with 425 horse turns 5100 rpm at 69 MPH on GPS.  I would think maybe your Tach is off.



this isnt a white boat with blue/pink/purple stripes is it??

Nope, this is a red and white tahiti.  I'm having the pump rebuilt by Tim at Place Diverters and I'll post up the numbers in a few weeks after I can take the boat out and see how she runs with a new pump. 

Alright guys, I need some help here. 

454BBC (passenger/2 bolt/ ~325HP). 
Berkeley JC pump. 

WOT - 4900 RPM & 46 MPH - Sea level with 4 adults
WOT - 5100 RPM & 50.6MPH - 3700' elevation - 1 adult.

Pulling a skier, the pump cavitates and doesn't produce much torque. 

Based on the above the assumption has been that the impeller was a C cut, which was causing the high RPMs and cavitation from a stop under load.  I was getting ready to send the pump out to get rebuilt with a new impeller so I pulled it apart and this is what I found inside.  A2 cut impeller, what looks to me like clean leading edges, no obvious issues.  So what gives?  Why are my RPMs so high and having trouble with the holeshot?   

Now I have no clue what to do with the pump rebuild.  I'm glad I might save some money on not needing a new impeller, but at a loss for performance issues. 

Do you still have these available?