1987 Mariner 30hp runs for a few seconds then shutts off

[wpg manitoba]

I Just purchased this motor and I think it is a lemon. It started up really easy but will only run from 10-90 seconds max and then just turns off like nothing. I started it up a few times and it does this over and over. Compression is good that Is one thing I know to check. I am assuming fuel or electrical problem? I really hope it's nothing serious like overheating, it pee's water alright, and when it shutts off its still fairly cold still.

 

[minuteman62-64]

Re: 1987 Mariner 30hp runs for a few seconds then shutts off

I doubt overheating would cause it to stop running after 10-90 seconds. I'd start with the fuel system. Is the tank vent OK? Fuel pump? Maybe when you pump up the bulb you get fuel to the carb, but the fuel pump can't keep up enough flow to keep running?

 

[wpg manitoba]

Re: 1987 Mariner 30hp runs for a few seconds then shutts off

I did get it to run longer once by pumping the primer continually but it still turned off when doing this.

 

[Maxz695]

Re: 1987 Mariner 30hp runs for a few seconds then shutts off

It sounds like the fuel pump needs replacement, but check for loose or cracked hoses. Also the primer bulb may be bad. The carb wil send gas to the engine until the bowl is emptied. If the fuel pump is not pumping the engine will stall from lack of fuel. Dosn,t sound like the engine is nessecarily bad