Boat motor losing fuel HELP!!!!!!!!!!!!!!!

[hornet22]

I'm at a loss. I have 2003 Mercury 50hp 2 stroke motor. My problem is when I idle or trolling at near idle speed i loose fuel pressure. If i pump the bulb i'm good to keep going. If i'm at WOT i'm good to go. I'm going to list everything i have done. Any help is appreciated!!!
Last fall i rebuilt the engine top to bottom all OEM parts. Runs great.
cleaned carbs (soaked, sprayed then air blow out)
just rebuilt them again last week (hoping this was the issue. NOT!!!!
replace line w/ bulb (1st one would collapse and not open till next day) replaced it again now losing pressure. I can pump it and leave it sitting it doesn't loose pressure.
I have replaced, pick up tube, check valve on tank, tried cracking the fuel cap, all fuel lines on motor, new quick connecter for fuel line both sets, replaced the T valve coming from the solenoid, i have rebuilt the fuel pump twice now, and anything simple you can think of i have checked or replaced.
Now sometimes when i pump the bulb as tight as it will go i can hear a slight squeal sound. not always but sometimes idk if thats what causing to loose the vacum and loose pressure. I have checked the floats to the book and they are within specs (not sure if i should adjust them anyways????
I'm out of ideas and ready to beat my head against the wall.

I have read about sycronizing the carbs? i think this is more a 4 stroke thing. not sure.

Also does the fuel solenoid (not sure exact name but it helps to crank boat when you push key in) be bad and causing the loss of vacuum? When i push key it clicks and if its warmed up and i push key it starts to bog down like its being flooded so it seems its working. But i read somewhere it could be working but losing vacum. Can you rebuild, or clean this item?

Please help!!!!!!!

 

[GA_Boater]

Rebuild the fuel pump. The diaphragm stretches and can't deliver enough gas at some speeds.

Pumping the bulb is the key clue.

 

[hornet22]

I just rebuilt it a few months back. would it already be bad? WOT everything is fine its just if its idling or at slow speeds.

 

[GA_Boater]

OK - How do you have the idle screws set?

 

[hornet22]

I just ordered rebuild kit for fuel pump just in case. This will be the 3rd rebuild since last fall rebuilding the engine (maybe i got a bad kit....idk) I have everything set to factory settings. I did a sync and link per the manual. Screws are 1 1/4 turn out on all 3 carbs. plugs are coffee brown. i have tried adjusting them in and out little at time makes no difference. One thing i forgot to mention. If i'm out of the water and have the muffs on it does fine. It will idle all day no prob. But in the water it won't. I have read it has something to do with the back pressure of the water. idk. just frustrating everytime i go out if i'm idleing around trying to find fish i have to keep pumping the bulb and sometimes it still won't recover. it empties the float bowls then i have to pump and struggle to crank someitmes. and sometimes it will fire right up.

 

[GA_Boater]

You have to fine tune the needles on the water cuz it has to overcome the water back pressure.

It can be done on the trailer. Keep the trailer tied down, back the trailer into the water deep enough for the water pump to work, put it in gear at idle and adjust away. Screw the top needle in til it stumbles, back it out til it stumbles and set it in the middle. Repeat for the other carb.

 

[hornet22]

ok....so i took apart the fuel pump and the paper gasket in the middle was torn! How it got torn idk but it is. I hope this wil fix my problem. Also i watched a video and a guy rebuilt a fuel pump just like mine and had a black round piece (looked like material the diaphragm is made from) before the clear plastic round piece. When i bought the boat several years ago i had to rebuild the fuel pump and it didn't have the black piece just the clear round disc. Do i need to have the black piece then the clear piece?

 

[hornet22]

I also have another question. I have a set of 60 hp carbs for my motor. I tried to use them when i rebuilt the motor but i could never get it to run past 1/4 throttle. I tried to advance the timing but still no luck. I want to solve my current issue first with the fuel issue but also wanted to ask about the 60 hp carbs. I did soak and rebuilt them also the way you should. It would idle fine (well best it could) but just bogs down past 1/4 throttle.
Would not advancing the timing be the main cause of this? How much should i advance the timing? do i need to change the BTDC setting also?

 

[roscoe]

You might want to do a compression check also.

In my opinion, problem is with fuel pump, compression to fuel pump, or possibly an air leak on one of the many fuel line connections.