2.5efi bogging SHOULD FUEL PRESSURE READ CONSTANT 39PSI??

[liberatorx2]

engine bogging down, loses from 300-1500rpms. does it when i gas it to get on plane or jump from 3000-5000rpms. when i level out i can run at steady rpms all day . Ran 25 GALLONS GAS THRU MOTO TODAY, BUT EVERY TIME I GAS IT TO TAKE OFF OR JUMP UP 1000RPMS OR SO IT WILL DROP OFF. I SWORE THIS WAS AN ELECTRICAL PROBLEM YESTERDAY BUT I WATCHED FUEL PRESSURE GAUGE [ RITE B-4 FUEL RAIL ] WHILE MY SON DROVE AND WHEN MOTO BOGGED THE PRESSURE GAUGE WENT FROM 39 TO 12. SHOULD GAUGE READ CONSTANT 39PSI????? WHAT COULD CAUSE THIS??? PLEASE HELP THIS IS A BRAND NEW POWER HEAD.DONT WONT TO DESTROY ANOTHERONE!!! RICK OH AND HAVE A BRAND NEW FUEL PUMP, IT BOGGS DOWN WITH BOTH OF THEM.

[patchesII]

i think the fuel pressure should stay 39 throughout the operating range. somebody else will jump in here pretty quick. btw where in east texas do you live and where do you boat.

[liberatorx2]

IF THE BRAIN OR SOMETHING ELECTRICAL ON THE MOTOR IS CAUSING THIS--WOULDNT THE GAUGE B-4 FUEL RAIL STILL READ STILL READ 39PSI?? BTW I LIVE IN ATLANTA TX & BOAT BIG CYPRUS BAYOU & WRIGHT PATMAN LAKE.

[Jay Smith]

Rick ,
You have a bad pump ( can be new and bad )make sure that when you bolt the pump to the boat that you don't squeeze the body of the pump to the mounting clamp it will fry it EVERYTIME or your regulator is bad.( My pick is bad regulator...) Check return lines and fuel pick up points in the tank. Make sure your tank is vented well also. The pressures on a 39 # regulator should NEVER go below 37# lbs ( AT ANYTIME ) if it does you could loose that new motor !!!! Be carefull !!!!!!!!!!!!!!!!!

[Techno]

One other thing it could be is the pumps wiring. It happened to someone before but I don't think the pressure dropped so drasticly. Its worth checking.

Bad connections, broken wires, green crustys on the terminals.

This is probably the biggest selling point for having a fuel pressure gauge on the dash. Instant trouble shooting.
Now you know that it can't fluctuate so it will be even more valuable.

[liberatorx2]

JAY, I HAVE 2 PUMPS, MY OLDER ONE AND BRAND NEW ONE. IT BOGGS WITH EITHER ONE. PRESSURE GAUGE IS B-4 FUEL RAIL. WHEN ENGINE BOGGS IT DROPS TO 12PSI. IF REGULATER IS BAD SHOULDNT PRESSURE GAUGE STILL STAY AT 39PSI???

[Techno]

The regulator is what is setting the 39 lbs pressure, not the pump.
Since it returns fuel to regulate, if it continues to do this when demand goes up then the pressure would drop.
Just like having a hole in the hose. The regulator adjusts the size of the leak.

[liberatorx2]

TECHNO , I FOLLOW WHAT YOUR SAYING, IS THERE A WAY TO CHECK REGULATOR WITHOUT JUST REPLACING IT ?? IF I DONT GET THIS FIGURED OUT SOON IM GONNA HAVE TO MAKE THE WIFE GET A 2ND JOB. SHE WAS MUMMBLING JUST NOW WHEN I GOT OUT OF BED [AGAIN] TO SEE IF I HAD ANY MORE REPLIES.HOW MUCH IS REGULATER?? i sure appreciate yalls help. PLEASE STAY WITH ME ON THIS. AND JAY I CAN TELL THERE'S A BEAST UNDER THERE WAITING TO BE RELEASED!! BUT DONT WORRY IM TAKEING IT EASY TILL ITS TIME & THINGS ARE STRAIGHT. THANKS RICK

[Greg Moss]

I have found that most fuel pumps require more current than the wires that most have hooked up to the pumps can supply. You really need to have a relay with 10-12 gauge wire going from the pump to the battery. Most installs that I have seen are only using the small 16 gauge wire from the key switch to the pump and runit all over the boat to get it there. Now you have tmuch line lose for that long of a run of wire to beable to supply the proper current to the pump. It is called brown out. a motor is going to develope the Horse power that it is designed to operate at wether it is doing it with the proper voltage or excess current draw. If the wire is not large enough to suppy the proper voltage then the motor will draw to much current and will damage the pump. I run all electric pumps through a relay. The higher you run the motor the more demand for fuel and if the pump cann't flow enough fuel because it isn't getting enough electricity to operate then you have a low pressure situation like you are exsperiencing now.

[liberatorx2]

GREG, I HAVE 10GA. WIRE FROM BATTERY TO PUMP & TO PUMP SWITCH. HEADED TO LAKE ABOUT 4PM TODAY TO TRY & NARROW PROBLEM DOWN SOME MORE. PLEASE KEEP EM COMING GUYS , I NEED AND APPRECIATE ALL THE HELP I CAN GET. RICK

[captcarb]

Check all of the lines for kinks or clogs, and check or just replace the filter. It could be the pickup also.

Jim

[Jay Smith]

Rick ,

I don't think you have an elecrtical problem but to put that issue to bed run a wire directly to the battery posts temporary with large gauge VERY SHORT ( 2 footish ) wires to the pump and see if the pump looses out. If not look toward the regulator or the pump, supply lines, or return line problem that was talked about earlier !

Good luck Buddy,

[Rickracer]

You can rule it out by simply pinching off the return hose momentarily, while you attempt to accelerate. If you still have the bog, or if fuel pressure drops too low, it can't be the regulator. Fuel pressure should be too high while the return line is pinched off. :cool:

[liberatorx2]

JUST GOT HOME FROM LAKE. MOTOR STILL BOGGING WHEN I TRY TO ACCELERATE.TOOK IT EASY TODAY, . ONLY PUNCHED IT 3-4 TIMES TODAY but it BOGGED AND DROPPED RPMS EVERY TIME! AS LONG AS I JUST EASE IT UP, THEN ITLL RUN STEADY RPMS ALL DAY . STILL HAVEN'T RAN IT OVER 4800-5000rpms. NOT GONNA TILL THIS IS FIXED! I'LL TRY again TOMMORROW WITH YALLS SUGGESTIONS. THANKS FOR THE HELP SO FAR & PLEASE DONT STOP TIL ITS OVER. I"M GETTING A HELL OF ALOT MORE ADVICE FROM THIS SITE THAN ANY 25$ DONATION THATS FOR SURE!!!!!!!!! I REALLY APPRECIATE IT , RICK MOORE

[liberatorx2]

JUST GOT BACK FROM LAKE AGAIN. PINCHED OFF FUEL RETURN LINE & ACCELERATED, SAME THING, ENGINE BOGGED & FUEL PRESSURE DROPPED. IT DIDNT DROP ALL THE WAY TO 12PSI BUT WHEN ITS PINCHED IT CLIMBS TO 80 OR 90, I ACCELERATE & IT BOGGS & DROPS WAY OFF. ANYBODY GOT ANY MORE IDEAS??? RICK

[captcarb]

You just proved you have a fuel delivery problem. Something is preventing the pump from delivering high flow for high power. It could be:

Pump problem, or pump not big enough

clogged filter

a restriction in the fuel line or the pickup

The return and the regulator are apparently ok.

Jim

[Greg Moss]

hook the pump dirrect and try again. look at the withdrawl tube in the tank some times they have a screen at the bottom and it clogs up. Make sure you get rid of the anti siphion valve. tyhose are POS and have burned may a motor up. Make dam sure you hook the pump direct to the battery do like Jay said Short heavy gauge wires. If it isn't spinning at the right speed it will supply pressure at low speed but not enough volume at high speed so the line will not fill and the pressure will drop! Do that and let us know how it works.

[Rickracer]

What is between the tank and the pump? Is there any filter? If so, has it been checked for blockage? Is it freeflowing enough? I had a problem once, (motor wouldn't get past 4500~5000) with a brand new (storebrand) filter that crossed over to a Wix 33033 between the tank and pump but it was too restrictive. I replaced it with a genuine Wix, and the problem was solved. 8000 +, no problem. If you have any filter inline between the tank and the pump, check it thoroughly. I'd start right at the tank and work my way forward (backward?) to the pump, and verify that everything is working as it should. :cool:

[espen]

Hi!
Maybe your pump are sucking air ? What is your fuel pump setup like ? Has your fuel system performed well in the way it is now without changes?
Can you hook the pump to an other fuel source ?

[Hank W]

charging or replacing your battery. I had a battery go bad this spring and my Promax would completely shut off and then immediately refire w/o me having to stop. Not the exact same problem as yours but could be the same cause. If my 40 amp alt. couldn't keep up, then your 16 surely can't.:confused:

[liberatorx2]

I HOOKED UP A TEMPORARY CLEAR FUEL RETURN LINE TO MY SURGE TANK TODAY. SAW WHAT LOOKED TO BE AIR BUBBLES WHEN I ACCELERATED HARD. REROUTED RET. LINE TO RETURN OUTLET ON MAIN TANK [ WHICH I PREVIOUSLY PLUGGED] & CAPPED OFF TOP OF SURGE TANK. NOW WHEN I ACCELERATE THE BOGG SEEMED TO HAVE DISAPPEARED.IT DID BOGG SLIGHTLY 3-4 TIMES WHILE HEADED DOWN RIVER, BUT NOTHING LIKE I"VE BEEN EXPERIANCING. I THINK I"M PULLING AIR FROM SOMEWHERE AND WAS FEEDING IT RITE BACK INTO SURGE TANK?? "QUESTION"!! IF AIR BUBBLES ARE IN FUEL GOING INTO ENGINE AND IT BOGGS THEN WHERE ARE AIR BUBBLES I SEE GOING THRU RETURN LINE COMING FROM?? AFTER READING THIS SEEMS LIKE IM NOT MAKING ANY SENSE. BOTTOM LINE IS SHOULD I BE SEEING AIR BUBBLES IN THE CLEAR RETURN LINE??????

[STV_Keith]

Sorry to jump in, but I got a quickie...the boat I bought back in May burnt #2 last weekend. When pulling the powerhead, we found a 1/4" fuel line going from the pump to the fuel rail, with a 5/16" return.

Other than it burning a piston, could that also have caused the motor to rev to 7k, then not go past that? I tried everything from a 22 to a 29 and it went to 7k each time. I thought it was in the rev box and swapped that, to the same result before it blew up.

[captcarb]

Keith,

Yes, and why don't you start a new thread?

Liberator,

Try eliminating the surge tank.

Jim

[MTCM]

Tried to call you but number didn't work. To eliminate possible surge tank and/or fuel tank problems, remove the surge tank and try another (portable) fuel tank temporarily.

[liberatorx2]

PUTTING ALL NEW EFI FUEL LINES IN NOW. CHECKED PIK UP TUBE NO PROBLEMS THERE & NO ANTI SIPHON BALL. I'LL LET YALL KNOW HOW IT GOES. THANKS RICK

[Jay Smith]

Hey Guys ,
The Surge Tank ain't the problem , Rick failed to tell ya it was doing the same thing BEFORE the instilation of the Surge Tank !Look somewhere else for the problem! I got tooooo many of em out there working with no problems !( Surge Tanks )

[Greg Moss]

I don't think that tank is the problem either. you may have a bad line collapsing or shreading on the inside. Once you get all the lines changed and do it with 3/8 and make sure it is not going to kink. I use a very heavy wall fuel line so there is no way the line can kink. I think if you can try it with a portable tank you will eliminate the tank and lines in the boat. Make sure you repalce all the lines fron the pump to the motor before you try the outboard tank.

[liberatorx2]

JAYS RIGHT IT AINT THE SURGE TANK AND I HAD THIS PROBLEM OFF & ON FROM WAY B-4 THAT. RAN ALL NEW 3/8 EFI LINES TODAY ,BYPASSED SURGE TANK AND NOW ITS WORSE!!I MEAN IT. DAMN THING IDLED FINE, TOOK OFF AND ITS BOGGING AGAIN. TANK P/U IS FINE, 3/8 TO BOSCH PUMP, 3/8 TO WIX FILTER, 3/8 TO MOTOR.IT'LL RUN FOR A MINUTE THEN BOGG LIKE S*%#.DIDN'T WANT TO TAKE ANY MORE CHANCES SO CARRIED IT TO GREG AT ROTHWELL MARINE IN ARK. HES GONNA CHECK OUT COMPUTER. EVERY TIME I RUN IT , IT ACTS A LITTLE DIFFERENT. ITS DRIVEN ME NUTTS!! IV'E TRIED ALL SUGGESTIONS & I APPRECIATE EVERY BIT OF ADVICE!!! THANKS A MILLION & I'LL LET YALL KNOW WHEN I HERE SOMETHING. RICK

[Sorry Dog]

This sounds just like a Gas Genset problem I was having at work. A natural gas powered v10 genset that backed up two 40 horse pumps. Would run one pump OK but when you put the second on it would bog the motor and kick the pump starters out.
I put a gauge on the gas line and said I had 10 inches pressure, Fine. Look at the gauge while running one: 2 inchs- not good but acceptable. Look at he while trying to run both and started pulling a vacuum - not good. So I have enough pressure at low loads but not enough at high loads so I can't deliver the volume of fuel needed. So to figure out where volume delivery is my problem, I put a gauge before the regulator to see if it drops too. In this case it does not so I know my problem is between the 2 gauges. Turns out to be so dufus put the wrong size orifice in the regulator. But I'm thinking if you put a tee in at the pump and filters and put a gauge in there that will help locate your restriction or volume problem.