7.4 454 mag, no power under load

[millertime016]

Have a 454 mag, changed wires and plugs and when I put it in the water for the first time this year everything seemed fine until I put a load on it. Engine will max out at about 2000 rpm, ran great last year.

Checked wire order a couple times, timing is ok.

Any ideas, thanks for the help?

 

[chiefalen]

compression test.

 

[guyjg]

Plugged fuel filters or weak pump.

 

[chiefalen]

guy's right also do a psi test on the fuel pump.

 

[Bt Doctur]

what kind of ign system does it have?
What plug order are you using?

 

[weekend_warrior]

I had the exact same problem, capped out at 2000 rpm on a 1994 7.4 454, bravo 1. After 4 days of troubleshooting, a 13 yo boy walking by and told me he had the same problem on an outboard club chase boat. He told me one of the plug wires was not seated properly. Sure enough, one of my plug wires was not fully pushed in on the #5 plug. I greased him $20. and went on my merry way at full rpms. Good luck!