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deadeye

Fuel System Stuff for a 63 merc 9.9

9 posts in this topic

My dad got a '63 Mercury 9.9 last year for his duck boat and we got it running but we are having some problems with fuel delivery. We pretty much narrowed it down to the fuel line plug that hooks up to the engine. The engine really runs good and gets the boat moving really good but after it is up on plane for a while it cuts out and dies. We figured out that if you mess with the plug connecting to the engine and squeeze the primer bulb it catches it's self and stays running. I was wondering if anyone knows where to get stuff (the fuel line and plug) for a motor this old. He really likes the motor (it is really cool looking) and would like to beable to use it for fishing/hunting. Any help would be very much appreciated!!! Thanks!!!
><>deadeye

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sounds like your fuel pump/diaphram is failing, try replacing that, 3-4$

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When trying to figure out fuel problems, it might be helpful to add an inexpensive clear glass in line filter, both to prove or disprove dirty gas, (I'm assuming that you also have a 1963 gas tank, and that could be flaking off pieces of rust into you're gas) but also so you can see what's happening with the fuel flow flow. The suggestion of a bad gas pump diaphragm is a good one. But you could also be losing prime from the fuel line connection, from a hair line crack in the bulb, from dirt in the fuel tank clogging the tank inlet screen, etc. That little connection might be purchased at Wal-Mart or any marine outlet store, and if you do that, I'd recommend you replace the entire bulb and gas line assembly as well.

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Thanks for the tips,
we replaced the pump diaphragm last year and it helped a little bit. It has a new tank, so I think that the fuel line sounds like it is the thing to blame. Do you think that wal-mart or whoever will have stuff for a motor that old?
><>deadeye

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I am assuming you eliminated the possibility that the tank vacuum relief isn't working.

I've had several different tanks in the past that wouldn't allow air into the tank and the tank would become under vacuum and the fuel pump will eventually be unable to fight the vacuum in the tank......Run great for 5 to 10 minutes then bog down and die (except when you manually squeeze the bulb).

If you haven't eliminated this option, run the motor with the fill cap off of the gas tank.

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wastewaterguru,
thanks for the tip! I will have to try that, I am not sure if it has the vacuum releif thing now that you mention that. I will let you know what happens, I am going to try to get the boat out tommorow so we will see what happens.
><>deadeye

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If the tank valve isn't alowing air in, then what you've discribed would be the result for sure .... or if there's air getting into the fule line. Best would be to try a friends tank and fuel line on your motor - Merc has used the same connector to motor for years. I've forgotten to open the tank air valve and had the same type result ,, and I've had leaks in the feed lines, balls and had the same result.

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I finnally got around to pulling the motor out today and as I started working on it I found that the connection of the fuel line to the motor is probably to blame. I pulled the part on the motor off and took the end off the fuel line and they are both banged up so I think that I found whats to blame. Now my question is where to get these parts? I went to gander mountain already today and they have nothing that would work. I was wondering if anyone knows where to get parts for a motor this old.
thanks for all the help!
><>deadeye

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Fleetfarm carries more stuff than Gander in the area of fuel connections.

If none of the modern fittings will work, then contact Twin City Outboard in Shakopee.

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