Pagan

[Damo]

Hey Ray, Just something I have just been through with my sons car which had me scratching my head also which mate be relative. He has a mechanical fuel pump on a 202 c/w tripple SU's , now the thing would start and run like a champion but the moment you started to stand on it it would die like fuel starvation. I would take off the fuel line and crank it over only to have fuel gush everywhere . Long story short is that while at idle the pump was working great but once it started to rev the return spring on the arm had become weak and not return the arm on the cam lobe just bouncing on the top thus not pumping and fuel Replaced the pump and it was all happy days. Maybe of some help , Cheers

[hookster]

Jesus Ray, can you make ABSOLUTELY SURE there is someone else there to video you running the boat "strapped to the trailer" please? The end result would be a viral hit on youtube and we could all possibly retire on the proceeds,

sincerely,


you know who

[The Spook]

Ray

Damo is possibly right. Go and buy an electric fuel pump and temporarily replace your mechanical fuel pump with it. Take the boat for a run, if it works you then know that your mechanical is not up to snuff.

I've played around with electric and mechanical over the years and when all else fails an electric pump that's working properly will always outperform a mechanical and isn't limited by the spring in the mechanical pump. Most mechanical pumps are limited by the spring to operate at not much more than 6000 rpm, with a faulty spring even less.

You don't have to find the most exotic electric pump around, a Holley red will suffice and it's rated to pump up to 97 US gallons per hour which is enough to handle most engines that run carbies. The only issue with them is that they are set at 7lb of fuel pressure and this may be too much for your carbie but its easy to fix. There is a pressure spring in them under a screw and you put an extra washer or two under the screw and it drops the pressure without affecting the volume. I've done it myself before with one on a boat of mine. The electric pump immediately fixed the fuel problem.

Spook

[rayza1]

Hey Spook, already tried an electric pump at Yarrawonga get together earlier this year with pretty much same results. Thats why this is so frustating, I'm really keen to see whats happening under real load conditions, but that involves having the boat in the water and that has it's own problems. I don't think it's a water issue as such because i can run it on the trailer with a hose attached indefinately. Going to have a play tomorrow.

[Waywood]

Where you off to tomorrow ? Got a day off and can offer a hand if you need. Matt

[The Spook]

Ray

I need to ask a couple of dumb questions.

1/ What sort of carbie are you using?

2/ Do you have any sort of filter in the fuel line?

3/ Does the carbie have a filter as part of its fuel inlet circuit?

4/ Have you checked all the jets to make sure that none of them are blocked?

The only other issues that I have had other than fuel pump, have all been fuel filter related. The hardest one to figure was with a Edelbrock 4 barrel carbie which had a little gauze filter behind the fuel inlet to the carb, it got clogged up and the boat would run at lower revs but as soon as I stood on it it would die because it would empty the fuel bowl.

The only other suggestion that I can make is to take any and all filters (if any) out of circuit and supply the fuel direct from the tank to the pump and from the pump to the carbie for a trial run. If that doesn't work then try another fuel tank. At some stage you will get down to the one thing you haven't changed and it could be the carbie.

Spook

[rayza1]

Thanks for the offer Matt, did an allnighter at work so had a late start today, so no water time! BUT, i have gone through the fuel system again (and again and again). Found that the top of the fuel pump had several loose screws when checking the diaphram, and the fuel tank while not having any solid rubbish in it did have some dirty fuel in the bottom. The inline fuel filter while not blocked was dirty so i have deep sixed it, the fuel pump has a gauze filter in it anyway. I'm going to try a primer bulb to get fuel to the carbies instead of using the electic fuel pump which although new i reccon i could pee harder, it's also one less thing to go wrong. I have simplified the system as much as i can, so.........we will see! As for what i'm running, It's a Standard Vangaurd 4 cylinder with 4 Amal carbies a worked head and cam and running a magneto driving through a V drive to a 2 blade prop. The motor also has zoomies. Cheers will keep you informed!

[The Spook]

Rayza

I don't know what to say, if you can piss harder than the electric pump then it's not much of a pump, new or not. I'm not an advertisement for Holley but the minimum I would use is a Holley red. In all the time that I've been playing around with Holden V8's I've never had one that cant feed enough fuel to an engine that I've used it on, and I cant piss harder than one.

For what its worth I've never found a standard Holden mechanical pump that will pump at more than 6000 rpm. I haven't had an engine that will rev less than 6700 rpm so there is an obvious issue with mechanical pumps. On every occasion that I have tried to use a standard mechanical pump I have had no joy and returned to the Holley pump and problem solved. The only other issues I have had have been fuel filter related due to lack of maintenance on my behalf.

So without trying to preach a sermon this is what I now use.

Fuel lines are 1/2 inch and all fittings are 1/2 inch. I even drill out the 1/2 inch fuel fittings. I use a metric drill set and find the biggest size drill that fits internally into the fittings and then go up half a millimeter and run that through the fitting, it doesn't sound like much but it all helps.

Fuel pickup tube is a 1/2 inch job welded into the bottom of the tank.

I use a replaceable canister style fuel filter which has ports in it capable of matching the fuel capacity of all the other 1/2 inch fuel lines and fittings and I replace the filter regularly.

The fuel pump is now an after market mechanical from a high performance mob in Wollongong which will handle according to them 8500 rpm. I believe them as I've had the current engine in 308 form to 8300 rpm with it.

I think that you need to have a bit of a think about a whole new fuel setup. There is no substitute for excess fuel capacity as long as you keep the fuel pressure down to a level that your carbies can handle

Spook

[NPeth]

Any luck Ray??????????

[rayza1]

Still no water time Nick, starting to get frustrating. Sounds healthy enough but have been there before.