Primer bulb doesnt stay hard

briaineo

Seaman
Joined
May 13, 2013
Messages
58
Hi

Was out in the boat over the weekend and the motor kept starving of fuel. It would bog down when I try to accelerate and the primer bulb would have to be pumped to keep the motor running

Works fine when I start up the motor after priming but dies when trying to accelerate. (some times will run for a few minutes)

I can see the odd air bubble arising from the tank end to the primer bulb.

The fuel pump has been rebuilt.

I was looking for some info on how to test the complete fuel system. Found a post here before on testing but cant find it now!
 
G

Guest

Guest
Re: Primer bulb doesnt stay hard

Did uou verifiy you gas lines are clear? You can get canned air and test all the gas lines are clear. Also the carb might need cleaning. What year and model is your outboard.
 

briaineo

Seaman
Joined
May 13, 2013
Messages
58
Re: Primer bulb doesnt stay hard

its a Mercury 402 (1974)

Carb was cleaned, fuel pump rebuilt, most lines replaced, only one that wasn't is the one from fuel pump to the carb. Will remove that and inspect it tonight. Have a can of canned air.
 

HopCar

Cadet
Joined
Jan 19, 2014
Messages
24
Re: Primer bulb doesnt stay hard

I had a similar problem once. The pick up tube in the tank was blocked.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Re: Primer bulb doesnt stay hard

How about tank venting? However this would be more of a "gee it runs great for about 5 minutes and then dies and won't start for 30 minutes" kind of thing.

Flat bulb means that there is a vacuum on the line between the bulb and the outside of the fuel tank.....somewhere along the fuel supply route..... aka blockage of some sort. One thing that goes along with what HopCar said may be a problem like I had once. I had a built in tank and put in some chemicals that were supposed to absorb water in the tank and they did. In the process however the water became a milky colored, gooey, blob and in my case made it's way up to the bulb where it blocked the line and shut me down. It could have just as well blocked the fuel inlet in the tank.

Mark
 

michaud500

Petty Officer 3rd Class
Joined
Sep 3, 2011
Messages
91
Re: Primer bulb doesnt stay hard

I had the same issue,it was a bad primer bulb. Make sure to get a Mercury primer bulb!! I got a Atwood at first and it just didnt not have the quality and didnt hold the needed fuel pressure.
 
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