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496 HO Fuel pump issue?

So, tried to start my engine up today for the first time after the winter. It did start as it normally does but died immediately, tried again a couple of times but it only ignited on a few cylinders and died so I understood that something was wrong. Fuel pump sounds normal when I turn the ignition on.
Checked the fuel line between the water separate filter and the fuel pump and it was dry. Poured some fuel in there and tried again, it fired right up but died after a couple of seconds. Did that a few times with the same result. It seems that the fuel pump doesn´t manage to draw fuel from the water separate filter (it is new and filled with fuel). No codes on the Scan tool. Engine is a 2004 @ 500hours Serial# OW008133. Last outing last fall it ran perfect from idle to wot. Hoping for some ideas what can have happen during the winter months?

what he said, fuel pressure will tell you the story,i just changed both my pumps and all good again.

Quote:

Originally Posted by TURBOED (Post 4691991)

what he said, fuel pressure will tell you the story,i just changed both my pumps and all good again.

Thanks for the advice! Sure I will test the fuel pressure but since it is starving for fuel I think I know what the result will be.
If I´m right and it is a bad fuel pump I am curious which part of it that possible can have gone bad and if I have to change the whole fuel pump, which part number is it?

Quote:

Originally Posted by SCANDINAVIAN (Post 4692006)

usually there is 2 pumps but I’m not sure what generation fuel system you have,usually Bup will chime in and will be able to tell you or take pictures and show us

BUP has posted about this a LOT I’m the past. Some of the cool fuel systems had terrible issues with inside paint pealing and ruining injectors. Note, this is all AFTER your fuel filters.

Do not run the boat any more even in diagnoses until you check this potential problem area out.

For one he did good by posting his engine serial number for starters and he has mentioned the water fuel sep filter so he SHOULD NOT HAVE GEN 3 cool fuel system. GEN 3 was the paint peeler and there is no way around it period.

the gen 2 cool fuel has other issues but mostly weak fuel pumps over time and as always crud in the fuel system but thats all marine engines over time Some way worse than others.

There is one big reason why the high pressure fuel pump becomes weak over time for all GEN 2 cool fuel systems ? Anyone what take a guess instead of me posting the why ?

couple of simple test first to try ?

Key on only fuel pressure is ??

Cranking engine fuel pressure is ?

this would be my first testing steps and then a remote fuel tank with fresh gas and a primer bulb to prime the fuel system all hooked to your first fuel inlet side of the engine. And again testing fuel pressure key on is and while cranking the engine over ? Does the engine start and will it start if you keep priming the bulb ?

Also when I did mine I did all new filters along with brand new fuel pressure regulator and screen at regulator,if you’re already there you might as well

This engine have 2 fuel pumps! Check if both work!
And serial number was wrong! Unknown in Merc system!
Michael

What hull is the motor in?just curious

Thanks for all your advice, especially BUP who always chime in with invaluable help to us 496 owners who is more or less desperate for some good advice. I have learned a lot reading your posts!

Got the engine running by using a primer bulb connected to an outboard tank. It fired right up and ran like normal. Fuel pressure when fuel pump running before cranking was 40 PSI and after start around 38PSI and while revving it up to 2500RPM it went down to 36PSI. Then I put the fuel hose back to the boats normal tank and started it up again. I was expecting it to stall but it ran like normal with the same fuel pressure. Fuel pressure seems to be on the lower side and I´m worried that it could lead to a lean condition while under load. After these tests, for the first time since new I opened up the fuel filter in the fuel cool pump. It was kind of blackish at the bottom but looked almost like new on ap 1/3 of it. No debris or water other than the blackish color. The cool fuel pump I have is a gen 3, the water/fuel sep filter that I mentioned earlier has been in the boat since I had my old 330/7,4L in it. The serial # is correct even if it seems to missing in the Merc system. Now I wonder if the best thing is to change both the high and low pressure pump while I´m on it or just test again with new fuel filter? Would it be a risk to test it under load in water? What is the board´s opinion?

I just thought I tell how my problem with the fuel pump was solved. I took the decision to change both high and low pressure pumps and after that the fuel pressure was back to normal again so I don´t know which of the pumps was causing the problem. I noticed that there were no signs of color flakes in my fuel pump after 550 hours, looked as new inside. It was a little tricky to get the pumps in the right position when putting the lid on, otherwise it was a easy job.

[QUOTE=TURBOED;4692124]

What hull is the motor in?just curious

TURBOED, the hull is a 30ft from a mold that I built together with some friends in the early 90´s. This is the first one that we built. It is lightweight, has a pad and a lot of strakes so it is pretty fast for a non stepped hull. Therefore it is also fuel efficient at cruise speed which is good with the fuel prices we have over here.

https://cimg3.ibsrv.net/gimg/www.off...193ddc1333.jpg
https://cimg5.ibsrv.net/gimg/www.off...6f60df6caf.jpg