1974 7.5 HP mercury wont accelerate

[gty2k2000]

i haqve a 1974 7.5 mercury i did a carb overhaul on it i changed the plugs and its still wont go over 1,500 some one help me

 

[NathanY]

Re: 1974 7.5 HP mercury wont accelerate

Does it have spark and compression on both cylinders? Did you check for spark or just assume with plug replacement?

 

[NathanY]

Re: 1974 7.5 HP mercury wont accelerate

Also does that motor have the integrated carb/fuelpump?

 

[gty2k2000]

Re: 1974 7.5 HP mercury wont accelerate

i checked the spark and it is very strong thanks to the replaced thunderbolt ignition. and it does have an intigrated feul pump system into the carb

 

[NathanY]

Re: 1974 7.5 HP mercury wont accelerate

When you rebuilt the carb, did you rebuild the fuel pump too?<br /><br />I am still thinking that this problem is fuel related, something still not right in the carb. Maybe sucking air through a fuel line, or maybe an unvented tank?

 

[gty2k2000]

Re: 1974 7.5 HP mercury wont accelerate

the feul line is brand new same witht the tank<br /><br />and i did rebuild the feul pump when i did the carb and i did use the diagram in a seloc manuale

 

[Motor Boater Bill]

Re: 1974 7.5 HP mercury wont accelerate

What does it do? Does it sputter and miss at that speed, or just accelerate to that speed and go no further? Did it do this before you did the carb overhaul? Have you checked the linkage to be sure the carb is opening all the way? Have you checked timing?