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Merc 50 HP 4 Stroke

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petroo

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Have a 2002 50 HP 4 stroke eng

Have a 2002 50 HP 4 stroke engine that won't start this season. I have check all of the fuel lines and pumped the bulb up. Seems like there is a small valve stem looking nipple on the fuel pump or what I think is the fule pump. When I push in the core of the stem it fires for aprox 5 seconds and dies again. The fuel filter is ok and fills up when I squeeze the fuel bulb and loosen the filter a little. It was running fine when I parked it last year. It does seem that the filter is not filling up on its own when it does run for a few econds... Help
 
"Gary, first you have to deter

"Gary, first you have to determine what part it is you are talking about and can then start troubleshooting.

If you year model is accurate, you have a fuel injected motor that has two different fuel pumps. Here's a diagram of what you should have...

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"
 
"Graham, you are absolutely ri

"Graham, you are absolutely right. It is just like the one you have here. When I took a better look at it I can tell that there is a good fuel suuply to the filter and the bulb is working right. I can also tell that the pump pulls fuel thru the filter so it made sence that when I loosened the filter cup I could see fuel come out the filter body by squeezing the bulb. I can get it to fire for aprox 5 seconds when I pump the bulb and relieve the schrader valve. It then imediatley dies. Any help you could give would be great.

Gary"
 
"Gary, if you water separating

"Gary, if you water separating filter isn't clogged (B), the next thing to check is the high pressure filter (I). At least those are the "cheaper" options.

It sounds like you have either a clog or your electric pump (high pressure) is acting up...."
 
"Got it fixed.. Went to the lo

"Got it fixed.. Went to the local Merc store and talked to one of the techs. He told me that the High Pressure pumps were famous for freezing up when not used for any long periods. He told me to ground the black wire on the top pump connector to simulate a demand signal from the EFI unit and activate the pump. Then tap lightly on the side of the Vapor Seperator unit . I did that 3 times and it fired up and started working properly. The engine now runs great again.

Thaks for the help, Gary"
 
"Well, I'm glad I guessed

"Well, I'm glad I guessed right about the high pressure pump, means I haven't totally lost it yet


and thanks for passing on the "quick fix", will have to make note of that as a "to do" before getting out the screwdriver..."
 
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