No Fuel Pressure!!!!!

[man-of-war]

HI ALL,<br />I had the boat out on the lake this weekend to start the break-in procedure. The fuel pressure was 6 psi when I launched it on Saturday. I ran the engine for 10 minutes then the pressure dropped to 5.5 psi. That's fine. I started the engine today for another run, the pressure was bouncing from 6 to 5.5 psi. I ran the engine for an hour between 2500 to 3000 rpm then I switched off the engine for about 3 minutes and then started it again. The pressure was now at 2.5 to 3 psi. I didn't like the look of that, so I bought the boat home to try to rectify the problem. I hooked it up to the garden hose and started it up. It read 0 psi. I tried shaking the gauge, no luck. I replaced the fuel line from the gas tank to the fuel/water separator, swapped fuel pumps, got the needle to 3 psi and removed the gauge. Then I applied compressed air and the needle moves. I bypassed the fuel/water separator direct from tank to fuel pump and still got a reading of 2.5 to 3 psi. The needle pulses. I installed a fuel filter between the carb and the fuel pump and the gas does not fill the filter - just about 1 cm full (I can tell that by holding the filter vertically)......HELP

 

[bomar76]

Re: No Fuel Pressure!!!!!

You are saying it ran on the hose w/ 0 fuel pressure????<br />Not likely, may run for a little while on the fuel that's in the carb bowl, but that's it.<br />Check the gauge, and especially the hose leading to the gauge.<br /><br />If it in fact is a low fuel pressue problem<br />Try:<br />Bad anti siphon Valve<br />Plugged vent line<br />Fuel tank is full of garbage

 

[Haut Medoc]

Re: No Fuel Pressure!!!!!

Clogged pick up screen or what Bomar76 sez, or a combo thereof....JK

 

[rbezdon]

Re: No Fuel Pressure!!!!!

is it electrical or mechanical?? If it mechanical is it the same one off of your old engine?? If it is you may be finding the cause of your original engine failure. A bad fuel pump can get gas in the oil and that is just where you came from. I hope you replaced the fuel pump with the new engine!!! It would a shame to ruin another $3000 engine for want of an $80 fuel pump!!

 

[KaGee]

Re: No Fuel Pressure!!!!!

What Ron said!

 

[man-of-war]

Re: No Fuel Pressure!!!!!

thanks for the replys,the engine was idling on 0 psi without stalling.ill start working on the gas tank and vent lines.its a mechanical fuel pump.im going to put the new one back on.....where do i find the anti siphone valve? thanks

 

[rbezdon]

Re: No Fuel Pressure!!!!!

Top of the tank where the fuel line from the pump goes. Usually a 90 degree "fitting", one end gets the rubber hose from the fuel pump or seperator if it is infront of the fuel pump. The other end screws into the tank and has the pick up tube screwed into it.<br /><br />PS: By the way, it is not possible for the engine even to idle for any length of time with 0 psi. Either you measuring device is wrong or the engine was getting fuel from somewhre else!! It can only run until the float bowl is empty and if 0 psi is really the case no fuel replaces what is in the bowl and it stops, plain and simple. 5 to 10 minute max!!! I would think your pressure gage is suspect. Get a known good new pump in there anyway. Don't risk that beautiful new 4 bolt engine!!!!

 

[man-of-war]

Re: No Fuel Pressure!!!!!

I did the vent line check and the siphon valve check and they're all clear. I also replaced the fuel pump rod and got a new fuel/water separator. I started the engine this morning and the gauge was reading 6 psi then dropped to 5.5 psi again. I started it up this afternoon and it was reading 0 psi. The needle was pulsing. I ordered another carter fuel pump for $180.00 to see if that gets rid of the problem. If not, then it isn't a problem with the pump but with either the gauge or cam. I was also looking for an electric fuel pump today but these things are noisy. The one the guy showed me for my application was a Holley blue. He said I need a switch on the dash and a relay thing. Why do you need a switch and relay to operate the pump? It should be like a car - turn the key and go....

 

[pine island fred]

Re: No Fuel Pressure!!!!!

Did you pick up on what j.kopec said? There is probably a finger filter in the pick up tube before the anti-siphon valve. First thing in the system. fred

 

[man-of-war]

Re: No Fuel Pressure!!!!!

well, the problem was none of the above.installed the new fuel pump today, started the engine 0 to 1 psi, I WAS FUMING.Took the liquid filed gauge off and hooked it up to my HVLP pressour pot, and set it at 6 psi,the liquid gauge gave a reading of 1 psi,i set the gauge to 15 psi to get 6psi on the liquid gauge .the problem with the liquid gauge was, the vent nipple behind th gauge i never cut it off.now its reading 5.5psi .......thanks ALL

 

[rbezdon]

Re: No Fuel Pressure!!!!!

man of war. Go back to the top of the posts. A couple of us pointed out the gauge HAD to be wrong or the engine could not run. It is a law of physics. No fuel pressure, no fuel flow. No flow, no fuel to run. Best to understand the problem and solution before throwing parts and lots of money at them.<br /><br />I am glad you have a good fuel pump though and it is working properly. I would love to hear that new engine run!! Good Luck!!

 

[man-of-war]

Re: No Fuel Pressure!!!!!

vetter41 thanks.the engine sounds good now,i had the mechanic install the original cam the boat came with.this cam gives a rough mild idle,it sounds as if its bubbling.im still in the breakin mode, i have 4 houres on the engine already, and 6 more to go.i had the mechanic give me a 60hour warrenty on the engine .......thanks again