MSD and losing rpm?

[Jetdriver]

I was running the boat rather hard this last weekend and I noticed that if I stayed in the throttle for more than about 30 seconds I would slowly drop about 200 rpm. What would cause this?
Setup is:
Gen V 454 with aluminum manifold and holley double pumper.
MSD 6?? its the marine one
MSD distributer
what else do you need to know?
http://www.***boat.com/image_center/data/520/79P1010222.JPG

[Infomaniac]

Probably fuel flow or floating the valves?

[Nucking futs]

Maybe the fuel delivery is not enough for the engine to hold the rpm and the engine is going to a lean condition??Have you done a plug reading after a WOT pass???
Just my 0.02 cents .Tim

[Jetdriver]

What would cause the valves to float? Im only spinning at 4800.

[Jetdriver]

Maybe the fuel delivery is not enough for the engine to hold the rpm and the engine is going to a lean condition??Have you done a plug reading after a WOT pass???
Just my 0.02 cents .Tim
I have not! Ill have to do that the next time Im out. Is it possble that my Holley blue is just a piece of shit?

[GofastRacer]

What would cause the valves to float? Im only spinning at 4800.
Wore out valve springs????..

[GofastRacer]

I have not! Ill have to do that the next time Im out. Is it possble that my Holley blue is just a piece of shit?
Those are a pice of shit, they will not maintain pressure!..

[Jetdriver]

Those are a pice of shit, they will not maintain pressure!..
Maybe Ill get a pressure gauge then and start there. Might be another winter project for the boat!

[chriscraftstinger222]

I've never liked those Holleys either. Always way too loud and very unreliable. I've been happy with the last two carters that I bought and will never buy a Holley again. Junk!

[GofastRacer]

Wanna test those Holley Blue's, just hook em up in a barrel and watch the flow drop after a while!..Want reliability, use a good 6 vane mechanical (Clay Smith for one) and a simple bypass after the carbs, end of problems!.. :wink:

[Jetdriver]

Wanna test those Holley Blue's, just hook em up in a barrel and watch the flow drop after a while!..Want reliability, use a good 6 vane mechanical (Clay Smith for one) and a simple bypass after the carbs, end of problems!.. :wink:
What do you mean by a bypass at the end of carbs?

[GofastRacer]

You put the bypass at the end not off the pump so the carbs get full volume and pressure!...

[Hallett19]

if you run an electric fuel pump, run a bottle of marvel mystery oil in your tanks, every time!! Its an old racers secret I heard from a couple old schoolers talking about gas these days and whatnot ! As far as your problem goes, I'm not sure, check your fuel pressure if you can, but its either that or you timing could be coming out.

[Jetdriver]

Thanks all! Ill be picking up a fuel pressure gauge sooN!

[moneysucker]

As far as a whole bottle per tank of marvel, I think it is a little excessive. 4 oz per 5 gal is what we run with C12 because race fuel or av gas are very dry and hard on lines and pumps and everything rubber as well as stripping off some oil from the cylinder walls.
Check the voltage to the MSD system. It could be a voltage drop. MSD doesn't like starving for power. Just one more possible cause.

[Jetdriver]

As far as a whole bottle per tank of marvel, I think it is a little excessive. 4 oz per 5 gal is what we run with C12 because race fuel or av gas are very dry and hard on lines and pumps and everything rubber as well as stripping off some oil from the cylinder walls.
Check the voltage to the MSD system. It could be a voltage drop. MSD doesn't like starving for power. Just one more possible cause.
OK will do!