high rev cut out???

« **on:** June 07, 2008, 07:50:46 PM »

I have got my boat running really well EXCEPT......... I run about 48-50 but the last 1/4 of the throttle is unused and when I get into that last of the throttle it cuts out and pops or rattles.
Someone said that I should check my powervalve in my Holley? Any other thoughts? I am running a BBC with an aftermarket aluminum intake and a Holley 3310. Can the powervalve only yeffect me at the high end and run well the rest of the time?

« **Reply #1 on:** June 07, 2008, 08:32:41 PM »

Sounds to me like not enough fuel flow, pressure guage? The carb maybe ok, but just running out of gas do to high volume usage and the fuel pump/line can't keep up.

Also could be an ignition issue, but fuel pressure at speed would really help to narrow it down.

« **Reply #2 on:** June 07, 2008, 08:43:35 PM »

if it cuts out on the big end you could have to small of jet on the secondary side. also if it pops and cracks you might have to much or not enough timing

« **Reply #3 on:** June 08, 2008, 02:44:59 PM »

We played with the timing and it seemd to have zero effect upon the problem at hand. I took the carb apart today and I cant find any blockages etc. I am truly at a loss!!!!!!

« **Reply #4 on:** June 08, 2008, 07:20:29 PM »

The key is you said - the last little bit. The last little bit is when the secondaries come into play so concentrate on that. Could be the secondary spring or the mains.

It is probably not the PV, those problems tend to show up under 3K.

What secondary spring do you have in there?

« **Reply #5 on:** June 08, 2008, 09:35:06 PM »

if you have an aftermarket ignition box like an MSD, make sure that the little rev limiter chip isnt set too low, because itll cause that, also, if you are running an old style points or even a standard HEI distributor it could not like the high rpms too.

« **Reply #6 on:** June 09, 2008, 09:28:40 AM »

I am running a standard hei. maybe if i replace the coil with an accel or something?

« **Reply #7 on:** June 09, 2008, 11:43:59 AM »

put an hei supercoil from accel so i will see tonight how she runs

« **Reply #8 on:** June 09, 2008, 09:10:26 PM »

didnt help! Will try condenser tomorrow as well as new cap and rotor! Who knows.

« **Reply #9 on:** June 09, 2008, 10:19:17 PM »

check the cap and rotor, see if theres a bunch of white buildup on the points, if there is use some really fine sand paper to clean it off, or just replace the cap and rotor, and if your distributor is older, you could try replacing the magnetic pickup.

« **Reply #10 on:** June 21, 2008, 02:28:50 PM »

I'd go about 1/4 mile wide open then shut it right down. Pull a spark plug and you'll know if it's the carb or not.

How are your plugs and wires, new, old worn out? Top end balls to the walls will allways show up the worst parts.... in a hurry

« **Reply #11 on:** June 22, 2008, 05:38:43 AM »

It could also be the plug wires arcing to something at max load.

« **Reply #12 on:** June 28, 2008, 02:27:27 AM »

Just wondering if you found the problem?

« **Reply #13 on:** June 30, 2008, 11:20:51 AM »

If you have not found the problem check your fuel filter , make sure it is allowing enough fuel to flow through it at high rpm's.

« **Reply #14 on:** July 15, 2008, 06:27:29 PM »

Seems that the problem was the HEI ! I am not sure why or what but when I put the old Mallory points distributor back on the issue stopped. Runs well now. I guess I will be looking for a new ignition set up! ANy suggestions with a budget in mind?

« **Reply #15 on:** July 15, 2008, 07:57:57 PM »

There is no budget when it comes to a boat

2sav

« **Reply #16 on:** July 15, 2008, 08:33:31 PM »

Quote from: countryboyaustin on July 15, 2008, 06:27:29 PM

Seems that the problem was the HEI ! I am not sure why or what but when I put the old Mallory points distributor back on the issue stopped. Runs well now. I guess I will be looking for a new ignition set up! ANy suggestions with a budget in mind?

MSD Ready To Run dizzy is great. You dont need the box to run one (although they run really well with a box) and they're super simple to hook up.

« **Reply #17 on:** July 16, 2008, 11:02:23 AM »

ran great! until i hit about 5700 then it took a dump everytime! points mallory runs better!

« **Reply #18 on:** July 16, 2008, 11:03:11 AM »

anyone know anything about procomp packages?

« **Reply #19 on:** July 16, 2008, 07:06:57 PM »

Quote from: countryboyaustin on July 16, 2008, 11:02:23 AM

ran great! until i hit about 5700 then it took a dump everytime! points mallory runs better!

Does your motor have a hydraulic cam? BBCs are noturious for floating valves at 5800 RPM with a hydraulic cam.

Also...what impeller cut are you running? 5700 seems a bit high unless youre makin some serious power or running a B or a C impeller. If youre spinning an A impeller naturally aspirated and hitting 5700 RPM I'd say you may be due for some pump work.

« **Reply #20 on:** July 17, 2008, 12:45:58 AM »

I have used at least 1/2 dozen DUI dist. they build it to what your running it in a simple 1 wire hook up gap your plugs at .055 and your off! I have run these back to back with MSD and on the Westech dyno it will give MSD a pretty good run for $279 ! Just trying to help, the are not just a stock hei with a coil, they are a well built product for the money, good luck! Oh and I also agree with some others, check your fuel press. not at an idle but when your at wot were the problem is. I can't tell you how many times people vome to my shop and tell me it has 8lbs of fuel press on the guage at an idle but you need at least 5lbs at wot! (wide open throttle) Keep us posted...."D"

« **Reply #21 on:** July 17, 2008, 12:31:27 PM »

motor is a stock hardin marin 454 with 8.5:1 compression. I have no guess about the cam. I have pulled the heads and had them gone through.

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