Mercruiser Fuel Pump Pressure?

alexander38 · Post by **alexander38** » Fri Oct 22, 2010 2:53 pm

I got to the point last yr that I almost put in elect. fuel pumps if I have any more troubles with I will. I already keep a extra one on the boat now and just ordered a carb yesterday from and e-bay dealer for $265.00 as a backup it sucks going somewhere and breaking down over the weekend.

alexander38 · Post by **alexander38** » Sat Oct 30, 2010 7:47 am

Ok here's a question for some of you motor heads . Been told that there a thing called a k-plug in side the Q-jet and that a lot of 1/4 mile guys and muscle car guys take it out and epoxi it to keep the carb from loading up. Your thought please.

prowlersfish · Post by **prowlersfish** » Sat Oct 30, 2010 9:12 am

there are 2 plugs on the bottom that can leak and cause flooding , there is a aftermarket part to fix this ( looks like a piece of foam) it won't last . best thing to do it to epoxy over these plugs ( not remove) never ha problem after that and I have done a lot of them over the years

rossjo · Post by **rossjo** » Sat Oct 30, 2010 9:16 am

When they leak - they leak all the time, right? Not just after running at 1,500RPM for 10 minutes or so (like mine).

JDDEN - have I got a deal for you - I'll swap you a Quadrajet for your TBFI ... deal?

prowlersfish · Post by **prowlersfish** » Sat Oct 30, 2010 9:43 am

They can , but are more noticeable after shut down and restart

jddens · Post by **jddens** » Sat Oct 30, 2010 12:03 pm

Captain Ross.......no deal, now if it were a Demon or Holley I'd consider it...........

rossjo · Post by **rossjo** » Sat Oct 30, 2010 12:11 pm

If it was a Demon, I'd put it on my Vette.

I wouldn't put a Holley on a boat. The spread-bore Qjet gets great gas mileage.

alexander38 · Post by **alexander38** » Sat Oct 30, 2010 9:49 pm

Ok, Paul now that we know you can work on these things. I'll drop one off at work for you

prowlersfish · Post by **prowlersfish** » Sat Oct 30, 2010 10:59 pm

No proplem I got a round file to put it in

prowlersfish · Post by **prowlersfish** » Sat Oct 30, 2010 11:01 pm

jddens wrote:Captain Ross.......no deal, now if it were a Demon or Holley I'd consider it...........

I always tought Holleys had Demons it them

rossjo · Post by **rossjo** » Sat Oct 30, 2010 11:05 pm

Thats my point .... Got a Holley on my Sunbeam Tiger ... but not worried about gas mileage there ....

rossjo · Post by **rossjo** » Mon Nov 15, 2010 7:28 pm

OK fellas - I swapped the Qjet from my Vette with my 26/454 ... ran great at idle for 15 minutes. Ran great at 1200 RPM for 15 minutes. Loaded up at 2,000 RPM ... so its the fuel pump, not the Qjet.

Put the Qjet back on the Vette and it runs great - as usual (left blackmarks in the driveway just like Tony Stewart).

Mercruiser Fuel Pump part # 861677T on order tomorrow.

After I emailed and called Teleflex, the losers at Teleflex tech support can't confirm what length cable I need to replace THEIR OWN CABLE I removed which measures 13' on the plastic jacket, so I'll GUESS and order a 15' cable.

On the 40 Mariner Magnum, my VOM indicates 0Volts on all spark plugs (can't be), but I bought a spark plug tester and the top 2 cylinders have no spark, while the bottom 2 are as weak as Teleflex support, so I'll buy a Mercury/Magnum 40 Switch Box instead of a Stator or Trigger (which both tested out OK) ...

Will have all 4 boats (+ canoe) and possibly another Whaler Montauk 17 running by the end of the week ...

Any suggestion on a dual helm temp gauge/sender setup for my Cummins? Mine are shot.

prowlersfish · Post by **prowlersfish** » Mon Nov 15, 2010 7:36 pm

Rossjo are you using VDO gagues ?? if so I know where to get the right senders

rossjo · Post by **rossjo** » Mon Nov 15, 2010 7:55 pm

I have the original black ones ... Smiths I believe?

The upper gauges were always off. I added resistors to bring them into spec, but this too failed over time.

You got a deal on VDOs? I'll replace the whole shooting match ... maybe even the wires ...

prowlersfish · Post by **prowlersfish** » Mon Nov 15, 2010 8:01 pm

you have mail not sure if its a deal but seemd pretty good