Boat-Holley Carb Experts!?!

I currently own a 1985 Ski Nautigue 2001 with a 351 ford motor with a Holley 4 bbl carb. Were having a very strange fuel issue that were trying to fix. At the end of last year we noticed after the boat was shut off you could look down the carb while the air filter was taken off an notice that both front and rear bbl would have fuel dripping in them and filling with fuel. So this spring we ordered a rebuild kit and installed that. The kit included all new gaskets,o-rings,needles and seats. The same none adjustable floats were used.When installing the kit made sure both front and rear floats were set properly.After the kit was installed it fixed the fuel leakage in the rear bbl. An slowed the drips in the front. But a new problem started. While trying to start the boat you need to feather the gas alittle to get her to crank. When doing this the front J tube on the front bbl wil shot a large amount of fuel out of it hitting the choke butterfly causing it to spray everywhere. Which is a huge fire concern. We have a brand new holley carb being shipped today for the boat. But we are still baffled on whats causing there to be so much pressure to have that fuel shot out of that front j-tube. Any ideas on what would be causing this is greatly appericated. Cause were worried that a new carb isnt going to be the answer and we need to get this fixed and were drawing blanks!!!

 

Had the same issue.... I have a 351 Windsor in my Mastercraft...

I thought it was the fuel pump going bad but I took it out and the spring was good ect (Manual Pump) Then I was told to try a alternate fuel tank.. I took a line and set it in a can and it ran fine... I also drained and cleaned my 20 Gallon Tank in the back.. I like to do this every 3 years or so...

Turned out to be the Marine Petcock Elbow on top of the tank was not venting causing the pressure in the line.... There is a Ball Bearing in it (Required from Coast Guard) .. The new Ethonal gas gummed it up... I took it out and sure enough the bearing and spring were getting stuck... Check yours out.... I will bet thats it...

 

Never heard of a j tube. If.you speaking of squirter than, check.your pressure regulator

 

do yourself a favor, throw the holley in the garbage and get a edelbrock, my dad went round and round with a holley on his 57 t bird he finally switched and in the end he never had to do anything to his edelbrock, its been on there for about 10-12 years

 

Sounds like it a pump shot from the accelerator pump. Been a long time since I've messed with a Holley tho.

 

Accelerator pump check ball not sealing... that would be my first SWAG

 

That's what I thought too at first glance. But the Accel pump shoots through the venturi *below* the choke plates.

"J-tube" is really the "bowl vent" on marine carbs. Took a second to remember that one from WAY back in the day.

I'm thinking the check ball over the accelerator pump isn't sealing which is causing the surge to back into the bowl and shoot out the J-tube.

OP could open the choke (motor off), and pump the throttle to see if the accelerator pump is not shooting out (or just dribbling a little) at the correct spot around the venturi.


PS: If this fixes it...me and my 1986 Connelly 65" Shortline 2 want a RIDE DAMMIT!!!!

 

I agree. I have a 1989 American Skier, 351W. New Edelbrock + new fuel pump equals a reliable boat. I don't like paddling!

 

We had a dual 750 Double Pump setup atop of a Tunnel Ram on our 19' Mantra Jet and I never had issues with the Holley's.

Dad has twin 650's on the blown 355 (30 Ford) and it runs good too..

Never ran the Edelbrock so I can't compare.

 

Sounds like the accelerator pump nozzle isn't in place on the primary side, there should be a nozzle straddling the venturi's on the front side held in place by a #4 phillips screw, Or possibly the float level on the front side is WAY too high.

The float level should be set with the engine running, remove the check plugs on the side of the bowls and adjust so fuel just slosh's out when you rock the boat gently.

There is nothing wrong with Holley carbs, they aren't quite as Idiot proof as the Carter/Edelbrock carbs but they work very well.

 

In addition to the post about the fuel tank....

A carb is purely mechanically operated, so to have fuel going down the barrels when there is no actuation, and no engine running is abnormal.

Rebuilding the carb probably sealed it up better, but I think you'll have to look for your problem down stream of the carb.

Fuel is delivered to the carb by pressurizing it.
Fuel cannot flow without an external force moving it. Even when you hold the throttle wide open, no additional fuel should flow other than the inital acuation squirt (engine not running).

I have a Holly 4bbl on my 352 Ford FE motor.

Anyways... look down stream for your problem... and good luck!

 

2 Rebuilds in 22 Years and my Holley is doing great...... Boat Carbs are different than Car Carbs for sure....

 

Would taking the fuel cap off while turning the motor over test and see if that elbow you mentioned is stuck and causing the pressure build up. If i unscrewed the fuel cap and took it off this should relieve the pressure in the tank if that elbow is gummed up causing an the pressure issue correct?

 

You don't mention the model Holley you have.

Does your carb have a metering block at both ends of the body?

Does your carb have just a metering plate on the rear bowel?

When you rebuilt the carb you did replace the power valve?

Lots of areas for heat leakage on metering blocks/plate.

 

Might help and might not.. Remember there is a Spring and a Ball Bearing in that Elbow... If gummed up it can stay locked closed (Like mine did) therefore the removal of the cap would do nothing if gummed up closed....:up: Again hook up a alternative fuel source and see what happens... If it still does it you know its the carb.. If not you know its from the pump back..

 

Dont know the model off the top of my head will get it and post it. Only has a metering block on the front bowel. An yes when i rebuilt the carb it came with a new power valve.

 

Is the elbow that you talking about a part of the tank itself. Cause i did do some work to the tank itself and pulled it out a tad to replace the a bad fuel sender unit. There is a elbow that is part of the tank itself but i didnt notice anything that could be removed from that elbow or is it somewhere done the line and has to be removed?

 

Suggest checking your fuel pressure. Make sure your not blowing past the needle and seat and overpressurizing the fuel bowl.

 

On my MC it is where the fuel line from the separator ect goes into the tank... Mine was a metal lL fittings with a spring and bearing.. nautiques might be different.. I did have to take my tank out to access it.. It's up top where the lines go in the tank....you should Definietly have one since our years are similar.

 

J tube means bowl vent right, then "Herbie" has real advice, if not too much fuel pressure, then "shit" on needle and seat. holy cow y'all.