40 Horsepower Mercury Mariner not getting full power

[timz]

Hi, new member here. I have a 40 horsepower Mercury mariner. I have let the boat sit for a couple years, and this summer have been working on it some. Have taken it out a couple of times. Here's the problem, the motor starts well with the choke. It will engage with throttle but then when the throttle is fully engaged the motor only runs at half speed. When the throttle is put into the neutral position, the motor will die. Anyone that can give me any pointers, I would gladly appreciate it. Thanks

 

[Vlad D Impeller]

Re: 40 Horsepower Mercury Mariner not getting full power

After sitting for a couple of years, you will definitely have to have the carbs cleaned and the fuelpump diaphrams replaced along with fresh fuel, also check and secure all of the fuel lines fittings against air leaks. Replace the impeller and replace the old gear oil in the lower unit.

 

[Mav23rick]

Re: 40 Horsepower Mercury Mariner not getting full power

It sound like you have the same motor I have, 40 HP 3cyl electric start. I have no power at full throttle after 30 min. of use. I am leaning toward a switch box and do an "on lake repair". I just read a posting about a simular problem a guy had w/ a 70 HP 3cyl. on this web sight. Tell me what you find out when you correct this prob. Mav... huntgide@charter.net