New to outboards looking for help

[parrot ridge]

We recently purchased a piece of property on the beautiful Meramec river in Missouri and with that we bought a used boat, a jon boat but a boat. it has a 1989 Mecury 50 hp outboard with an aftermarket jet on it. The problem is that it seems to have fuel problems after running for a while (40+ min). Cut out and will not run but at very low rpms. any ideas or further questions?

 

[Texasmark]

A plugged fuel cap on the fuel tank can cause what you say. The tank develops a vacuum since air can't replace the fuel the is pumped out and the pump can't overcome the vacuum.

Next on that older boat, its probably time for new fuel lines anyway, internal and external. They crack and the interior degrades into little black specks that clog your fuel filter and carburetor jets.

 

[parrot ridge]

A plugged fuel cap on the fuel tank can cause what you say. The tank develops a vacuum since air can't replace the fuel the is pumped out and the pump can't overcome the vacuum.

Next on that older boat, its probably time for new fuel lines anyway, internal and external. They crack and the interior degrades into little black specks that clog your fuel filter and carburetor jets.

Thanks, I did a little more searching and the venting on the gas tank is looking to be the most likely. The lines and filter are new.
As mentioned I am new at a jet boat but have been on one river or another river in canoes to wooden speed boats but never in a jet boat. I have at least become comfortable with the steering handling of the boat and do love it. We purchased a cheap aluminum john boat with an old Merc 50 hp on it to get on the water. Now we are looking ahead and are wondering what to dream for or strive to achieve as far as jet boats go. We are on the Meramec river and it gets shallow, (6 inch) but also gets tough to navigate due to trees and such. The inboards sure do look tempting but are they necessary? will a properly matched and adjusted outboard give me a comparable performance?

 

[parrot ridge]

Well we have installed new gas tanks, new bubble line and new quick connect fittings on the tank. I seemed to run a little better but after a short run it started falling on its face at the higher end of the RPM range. Although the filter was replaced and the carbs were rebuilt before purchasing the boat I still believe it is fuel related and am thinking about replacing the fuel filter and the fuel pump, any ideas?????

Thanks, I did a little more searching and the venting on the gas tank is looking to be the most likely. The lines and filter are new.
As mentioned I am new at a jet boat but have been on one river or another river in canoes to wooden speed boats but never in a jet boat. I have at least become comfortable with the steering handling of the boat and do love it. We purchased a cheap aluminum john boat with an old Merc 50 hp on it to get on the water. Now we are looking ahead and are wondering what to dream for or strive to achieve as far as jet boats go. We are on the Meramec river and it gets shallow, (6 inch) but also gets tough to navigate due to trees and such. The inboards sure do look tempting but are they necessary? will a properly matched and adjusted outboard give me a comparable performance?

 

[parrot ridge]

can a fuel cap trouble damage the fuel pump?

A plugged fuel cap on the fuel tank can cause what you say. The tank develops a vacuum since air can't replace the fuel the is pumped out and the pump can't overcome the vacuum.

Next on that older boat, its probably time for new fuel lines anyway, internal and external. They crack and the interior degrades into little black specks that clog your fuel filter and carburetor jets.