Author Topic: Fuel pressure issue? or volume issue? in a Boat.  (Read 2339 times)

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5363
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #15 on: June 28, 2021, 04:54:46 AM »
They are Marine units and look fine from what I can see of them except they have the wrong accl pumps in them.  The "generic" pumps from over the counter rebuild kits were cut at the top for the rubber boot/seal that was only used on early Pontiac Ram Air carbs.  Those pumps did not have the later short skirt seal and garter spring to keep in in contact with the pump bore, no crimped on retainer to keep the shaft from pulling out of it, and they were WAY too long to work correctly in a Marine application.

I'll also add that the factory didn't use the same specs in them for the idle system.  I've had matched pairs for the Crusader 350's sent here that had different size idle tubes and upper IAB's.  I thought the first few times I saw this that it was a factory mistake on the assembly line but have seen enough of them like that now that they simply may altered the specs for one reason or another during production runs........Cliff

Offline old cars

  • Carb lover
  • ***
  • Posts: 131
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #16 on: June 28, 2021, 05:07:01 AM »
Well pictures are worth a thousand words. Good call on the accelerator pump.

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5363
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #17 on: June 28, 2021, 05:16:47 AM »
If you read thru some of my lengthy comments on this thread I mention Marine accl pumps being different than automotive.

VERY IMPORTANT to use the correct pumps in them so there is some pump shot left to prevent stumble/hesitation/bog when already up on a plane and moving the Morse controls ahead to speed up the boat. 

If you use a automotive pump there is no pump shot left in that scenario.  The factory knew this, or at least figured it out and used very short pumps in Marine units.

With that said every single troubled Marine Q-jet sent here for me to rebuild it again has the WRONG pump in it.  They are also putting the wrong duration spring on them (in some kits where you get the complete assembly), too long and too many coils so they "stack" when compressed.

The light blue "soft" seal isn't worth two squirts of duck poop either, and the black ones are even worse, but I like the fact that they sell them and folks think they are good to go installing them.   Some weeks I sell so many pumps I can hardly get anything else done!............Cliff

Offline Pale Rider

  • Garage guy
  • **
  • Posts: 12
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #18 on: June 28, 2021, 08:25:34 AM »
ok, here is a bit better info.
17085220
1225  HKP

pics provided: franken carb

Offline Pale Rider

  • Garage guy
  • **
  • Posts: 12
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #19 on: June 28, 2021, 08:26:52 AM »
Cliff, I must be crazy bc I can still see a visible bump in the primary bore, what does this mean?

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5363
Re: Fuel pressure issue? or volume issue? in a Boat.
« Reply #20 on: June 28, 2021, 11:51:29 AM »
It's built from a 1985 truck carb, so a larger casting.

Your engine wouldn't really care one way or the other as the power level isn't close to where it would need that much CFM......