Starting problem...fuel pump?

AZ238

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Jun 11, 2010
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Hello everyone, I don't usually ask for help, but here I am.
A little background, Its a 2007 Azure 238 with mercruiser 350 mag MPFI / bravo 3. (Engine serial # OW665464) I bought it new and it has a whole 85 hrs on it. Its been stored inside or under carport and cover its entire life. Its in great shape and never given me problems.
My story starts with being on the lake this summer and noticing my cool fuel module with a crack down the side leaking water. I'm pretty mechanically inclined with cars, and I'll learn some things to do it myself. I bought the new revised module, new fuel filter and disc. While I was doing that I changed the water pump impeller, cap, rotor, plug wires and plugs.
I got it all back together, put fuel in the fuel filter hole. Turn the key, and can hear the pump(s) kick on for a few seconds, try to start and it just cranks. Did the key a few times to see if needing to make sure there was enough fuel to the pumps to start. No change. I put a little cap of gas in the throttle body and it started for a few seconds and died. The fuel module fuel inlet has fuel and pressure when I remove it, so its pulling fuel to that point. Doing some reading there is a low pressure one close to the filter and a high pressure one. Is there a shraeder valve to hook a gauge to see pressure? So has the high pressure pump gone out? It worked great the day I checked it before tearing it all apart. By the way, on the plugs and plug wires, I did one complete one before moving on to the next one, I wasn't gonna have that problem too. lol.
Thank you for any help.
.
 

AZ238

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Jun 11, 2010
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Thank you for the response, didn't realize I was in the outboards section.
 

alldodge

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No issue, the mod will move soon to the Merc section so it will get more folks looking
 

AZ238

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Jun 11, 2010
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Looks like I'm having the same problem as aggiekid. "No fuel pressure". Thank you alldodge for the help.
Update. I found the shraeder valve and tried to bleed it. I'm getting no fuel through it with the key and pump cycling on a number of times. I took the fuel module off again and tried the pumps out the of the module. The low pressure pump appeared to work, but not the high pressure one. Luckily i had bought another fuel pump, and tried it again. This time both pumps seemed to work. I put it all back together again. Primed the fuel filter side and turned the key to check fuel at shraeder valve. The pumps definitely sound different, like its moving fuel. But theres none to the shraeder. At this point, I'm not sure what else to try. What else can i try.??
 

Searay205

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i know when i changed my fuel filter i had to cycle for ever for it to fill. just a guess maybe hold schrader valve open while cycling get the air out. obviously it could spray fuel everywhere so take necessary precautions.
 

alldodge

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Remove the fuel filter to see if its still full or if its not.

If its not full, then the pump is trying to move fuel but its unable to draw fuel from the tank. If this is the case, take a gas can and longer length of gas line and connect to the fuel filter. Re-fill filter and place gas line into the can. Cycle the key on/off and see if fuel shows up at the rail.

If it is filter is full when removed, then there is an air leak in the fuel line between filter and pump
 

AZ238

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Jun 11, 2010
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Thank you for the info. I looked at fuel filter and it is full after doing the priming. The fuel module is the one that is both that and pump. So there’s a vacuum leak / crack in the module? Ok thank you.
 

alldodge

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Get a length or gas line and connect to fuel module, and place the other end into a gas can. Try running it this way. If it does run then the issue is the tank, if it still doesn't then its inside the pump
 

AZ238

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Jun 11, 2010
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Thank you for the reply, I tried a clear line into a can today. It did not pull any fuel. So I've taken the module off again. (getting pretty good at it now...lol) Both pumps buzz hooked to power, wired only one way. I don't know if this makes a difference the low pressure pump lower rubber bushing/ isolator was torn down one side. I put it back together. And the fuel regulator on top had some delaminated paint on it. I cleaned that top part all up, blew it out. Could one of those things cause it to not pull fuel?
 

alldodge

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If pump is sucking from inside the module and not the line it will just circulate the same fuel. All seals need to be in good shape

Gen 3 cool fuel flow.jpg
 

AZ238

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Jun 11, 2010
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Alldodge you were right. I wanted to let you and anyone else needing this info know. I took the module out again, the low fuel pressure pump isolator gasket was not sitting flush in its hole in the module. I superglued it and put it back together, filled it with fuel. I tried the shraeder valve first and fuel show out of there with a second or two. Then started right up and ran smooth. Thanks again for the help everyone. Had a great weekend with the boat.
 
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