4 more cylinders to what i'm used to

Hi guys back again,
We've got a 5.8l ford PCM 351 I'n a 1980 ski nautique. Recently we've changed plugs, leads, condenser, rotor, full carb refurb, battery and some more

The engine idols great, and engages gear and plods nicely, it's when you put the hammer down there's a problem. The power seams to surge, no shudder or clunking just not picking up smoothly or properly

Were now scratching heads about fuel lines or pumps? Another clue could that today the hand pump ball thing you use to prime or pump fuel in by hand sucked itself inwards while running.

Another strange thing is that out of gear and on land (with hose to intake) the engine sounds like it picks up to high revs 'cleanly'

It's a holley 4 bbl by the way

Any clues anyone

Thanks a lot ps Hi its Geoff this time. The above was written by my sons. The problem really is that the secondary butterflies aren't opening and when forced to open there is little fuel coming through the secondary jets. Wonder if the secondery vacume diaphram has been damaged by trying to find out the firing sequence. Engine plate found in bilge, the reason we had dripping primarys seems to be my fault, excellerator pump incorrectly adusted, i hadn't adjusted the clearence with the pump compressed, at least i own up to my own mistakes
.Have a good weekend, Geoff, Matthew and Tom

Since the primer bulb is collapsing, I'd say something is blocking fuel flow from the tank. Check your anti siphon valve on the tank top and also your fuel line from the tank to the fuel pump. With age and the ethanol fuels, it's known to collapse.

So do the secondaries not open when the engines not I'n gear (under load) or did you mean something else?

I'm gonna start with fuel lines/ tank blockages

Good morning, well it is here.
No 1 The ball pump is just there so when its stood for some time (weeks) you don't need to crank the motor over just to fill the carbs.
No 2 There is an issue with the fuel line from the tank and perhaps there may be a blockage in the internal pick up pipe in the tank. I'll put an air line on that and see ( this wasn't the original fault ) To get the boat back, we put a fuel line directly in to a one gallon gas can. So at this moment in time can rule out anything before the pump.
No 3 Fuel tank connection its not a barb fitting, its straight onto the tank.

No4 Under load, i mean when the boat is on the water and in gear, from 20mph up.
No 5 Correct me if i'm wrong, when the primary butterflies open, a vaccume is created in the inlet manifold, when this vacume reaches a certain negative pressure, the secondary butterflies open. On the port side of the engine, there is a diaphram, is this used as a damper (spring) or does it operatate the butterflies?
No 6 The Holly has what you call a boost valve, what does it control, is it fuel or vacume for the butterflies?
No 7 Everybody has stated that the secondarys don't open while on the trailer in neutral, unless my age is getting to me, i'm sure i see the secondary butterflies open with gallons of fuel coming out of the secondary venturies when the revs have been taken up to max by blipping the throttle (you see the kids at the traffic lights waiting for green thinking they're at the start of the indy 500, thats what i mean) and why did i do it, cos it sounds nice. Thats when i've seen the butterfies open. Thanks all, Geoff

Still struggling everyone,

Today we've changed fuel line and removed manual bulb, were pretty sure it's nothing to do with that now

(grumpy) Geoff will probably blog and correct me later but the diaphragm in the housing next to the choke that opens the secondaries had blown itself inside out, I think this might be due to some back firing after getting the firing order wrong

Really scratching heads now as we ran it about 2 weeks ago and top end was fine, but it wouldn't idle. That's why we tried changing all the ignition components. Now it seems to idle fine but appears lumpy or like it's missing ( although don't think it is actually missing) when you accelerate.

What about coil? What about vacuum leak? Where should we look for one?

(grumpy) Geoff has tonight revealed he's not 100% about the gasket between the carb and the block itself as the ones to choose from in the kit weren't exactly the same (only for that one )...that's how confused and running out of ideas we are...so depressed now lol :(

P.s he has done his homework on the Holley site as suggested so he can have some brownie points for that

Thanks for any ideas, Matt

Thanks John,

We did use a strobe light for the timing and have altered it, is that what u meant? I know Geoff (my dad) did take the distributor apart today to look inside at the advance/retard mechanism and was wondering about the springs being loose in there..I think he's gone off to have a think about that, it's about midnight here now so I'll ask him I'n the morning

I think he thinks he may have over adjusted the floats to compensate for some of the ignition issues. Do you think float settings might cause some of the symptoms?

I'll make sure Geoff reads all this in the morning, and suggest we put everything back to default and start again

What your all suggesting will make more sense to him, I'm an office monkey sho just wants to use it, he's the pit crew

Cheers all

Although the condenser didn't seem to fit, most likely it will work. It's only purpose is to quench the arc when the point contacts open. When they open on the DC current, there is a pretty big arc that burns up the point set contacts.

I feel you had better go back to your supplier with all the part #'s and find out what happened.