Mercury 25 will only run full thrttle for 30 seconds then die

[frobotz]

My 1992 mercury 25 2 stroke ran great. I upgraded to a larger fuel tank, That's when problems started. Left the boat in the back yard and the crappy Atwood tank swelled up and leaked fuel all over the place Hull had about a gallon in it. Well new tank (still atwood but I leave the cap vented so this wont happen again till I can build an aluminum tank) new fuel lines. all connections sealed well. Motor starts and run great if you only go to 3/4 throttle. if you go full throttle it will run for about 30 seconds then fall on its face. You have to hit the primer bulb to keep it running. I cant find any leaks anywhere in the system. Everything sealed. I even ran the fuel line straight out of the tank to bypass the tank connection. Still does the same thing.

Getting frustrated. Thinks it could have over pressurized the fuel pump or damaged a diaphragm in the carb. Gonne pull it apart tonight and have a look.

Anyhow does anyone have any other ideas? I just cant find the leak anywhere in the fuel lines or connections so it seems logical that maybe its in the fuel pump.

 

[flyingscott]

Sounds like a fuel pump issue.

 

[MH Hawker]

Sounds like a fuel pump issue.

i agree over pressure in the tank may of popped the fuel pump

 

[frobotz]

Agreed, I pulled he carb while I waited for a reply and had a look at the pump, It has 2 small holes in it now. Unfortunately I cant find anyone including Iboats with the kit and I don't use ebay...
Great troubleshooting folks.

 

[frobotz]

Any suggestions for parts? I live in Oklahoma sity if that helps. Our local shop doesn't have them either.

 

[frobotz]

No Title

HERE IS MY PUMP DIAPHRAM

 

[frobotz]

No Title

And this is why I need a new one.

 

[flyingscott]

Any mercury dealer should be able to get that for for you. I don't believe the aftermarket kit is available anymore

Carb kit is part # 1395-9761 1
fuel pump# is 1395-9702
Double check these but I believe one of these are what you need

 

[frobotz]

Thanks, I got a call into iboats to see if they can find the correct part. I believe those numbers are correct but the sales folks and myself are having a hard time. They are calling sierra to verify the kit.. Thanks for the help.

 

[flyingscott]

Sierra no longer makes the kit factory only.

 

[frobotz]

Ok. I found a few online so I guess I will order them tomorrow. Mae a temp one today and its working good again. Time to hit the water for some catfishing tonight. Thanks everyone.