Possible fuel pump problem?

[bronxlatetour]

I own a 1990 Sea ray 250DA with the 7.4 Bravo Mercruiser with 330 HP. The engine has aprox 335 hours on it. I recently changed the plugs/cap/rotor/wires/fuel-water separator. After changing the fule filter, the engine wouldn't start. After speaking with a friend I took the filter off and noticed that it was only aprox half filled with fuel when the original time that I took it off it was spilling fuel as soon as I began to unscrew it. After filling it to the top with fuel it started and ran fine.(In my driveway) I took the boat out into the ocean yesterday, ran fine. After it the engine was off for aprox 1 hour it wouldn't start. I once again checked the fuel separator and saw that it was only aprox half full. After getting towed home, I filled it again to the top and the engine ran great. I then cranked the front castor wheel on the trailor all of the way down(tilting the boat forward) and after a little while, the engine stalled out and wouldn't start until I did the same procedure of filling the fuel/water separator to the top again. No water in the fuel, I've checked. Could it be fuel is draining back into the tank and the pump doesn't have enough pressure to fill it again and get it to the carb?

 

[Don S]

Re: Possible fuel pump problem?

Could be your fuel pump, might check your engine oil and see if it's getting diluted with gas. IF the pump leaks, it could leak into the oil pan.<br />Could also be an air leak in your fuel filter or the boat fuel system suppling fuel to the fuel pump. Read this thread on testing the boats fuel system.<br /><br /> http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

 

[lilmandavis]

Re: Possible fuel pump problem?

make sure there isnt an old gasket stuck up in the filter housing.

 

[bronxlatetour]

Re: Possible fuel pump problem?

The oil looks real clean, I'm not exactly sure how to tell if fuel were in it. It looks as though it were changed recently as it was. There isn't any extra gasket stuck against the base.

 

[Don S]

Re: Possible fuel pump problem?

Smell it and feel it. If there is a lot of gas in the oil, when you wipe the dipstick with your fingers, the gas will soak into your fingers and evaporate quickly, unlike the oil. My guess is you have an air leak into your fuel system somewere, time to start troubleshooting.

 

[bronxlatetour]

Re: Possible fuel pump problem?

Is there a way to check the pump and what pressure it should be at?

 

[Don S]

Re: Possible fuel pump problem?

Sure, just hook up a pressure gauge between the fuel pump and the carb and run the engine.<br />PS: Don't even think about cutting that steel line to tee in the gauge. <br />Disconnect/remove the tube, and with the proper sized fittings and hose, make up a tee for the gauge.

 

[bronxlatetour]

Re: Possible fuel pump problem?

I was hoping to diagnos this myself but this is getting to be more than I am capable of.

 

[bronxlatetour]

Re: Possible fuel pump problem?

^

 

[bomar76]

Re: Possible fuel pump problem?

Originally posted by 90sea ray:<br /> I was hoping to diagnos this myself but this is getting to be more than I am capable of.

You have been given advice on how to diagnose the problem...if you are unwilling/unable to follow the advice.....<br />Well....then it's time to drag it to a marine mechanic.

 

[bamadave]

Re: Possible fuel pump problem?

Ray, don't feel bad having to take the boat to the shop. With a problem that can leave you stranded on the water, best to have it checked out if you're uncomfortable with with the diagnostics.

 

[bronxlatetour]

Re: Possible fuel pump problem?

I had a friend who is an auto mechanic look at it and all but confirmed that the fuel pump is bad. It apparently has just enough pressure to keep the engine running but not enough to fill the fuel/water filter. Also can a bad fuel pump let fuel drain out of the filter? I'm going to attempt to chang this myself, are there any major pitfalls I should look out for? Thanks for any advise/suggestions. One other thing, I was told that my engine could have one of two fuel pumps, is there any way to tell before I take it off? My serial number is....OD376979 Thank you.

 

[Don S]

Re: Possible fuel pump problem?

I had a friend who is an auto mechanic look at it and all but confirmed

All but confirmed <br /><br />I hope your auto mechanic friend and you realize that you need a MARINE fuel pump, NOT an automotive one.<br /><br />The fuel filter is on the suction side of the pump, so pressure has nothing to do with filling the fuel filter. And an air leak or plug in the fuel tank or lines will sure cause your problem.<br />You better go to that link I gave you earlier and recheck some things before you replace that pump.<br /><br />Merc lists 2 different part numbers, one for an Airex and another for a Carter, but both are now supeceded to a single number 862048A 1.

 

[bronxlatetour]

Re: Possible fuel pump problem?

Ok, I guess I'm back to the drawing board. Just when I thought I had it figured out. Thank you for setting me straight.

 

[pike hunter]

Re: Possible fuel pump problem?

Could be your fuel pump, might check your engine oil and see if it's getting diluted with gas. IF the pump leaks, it could leak into the oil pan.<br />Could also be an air leak in your fuel filter or the boat fuel system suppling fuel to the fuel pump. Read this thread on testing the boats fuel system.<br /><br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=015221#000000

I'm trying to get back that message from you're link but it doesn't work.
Thank you

 

[Don S]

Re: Possible fuel pump problem?

That thread probably exists somewhere in the archives, but the search feature is basically JUNK
I did repost it and will go up on this thread and edit it so the link will work.
The new thread is at this link:


http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

 

[pike hunter]

Re: Possible fuel pump problem?

That thread probably exists somewhere in the archives, but the search feature is basically JUNK
I did repost it and will go up on this thread and edit it so the link will work.
The new thread is at this link:


http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

Thank's a lot. Now it is in a safe file.d

 

[tystick]

Re: Possible fuel pump problem?


I would venture to say that you screwed up something when changing fuel filter.
If it started fine before changing out filter than pump would not be at the root of the no fuel/ no start symptom.
Although it has been known to happen that fixing one issue causes another issue
(I though that was only for jag owners)

 

[bamadave]

Re: Possible fuel pump problem?

Make sure nobody has screwed with the vent on the fuel filler cap. If the vent has been closed, could do the same thing?