Loss of power

[PJM10]

1990 Cobia. 5.7 Mercruiser. Upon throttle when I tried to trim it out it backfires and I lose power. (Whether I used my trim or trim tabs). Then I just lost most of my power. I limped back at about 7mph under a load. At very low speeds there is no problem. Any suggestions?

 

[PJM10]

Re: Loss of power

I appreciate all the replys. (0). In case anyone was interested it was corrosion on the dual battery switch. Also a stuck float in the carb. I fixed it myself............

 

[Chromaflage]

Re: Loss of power

I know this is an old thread, but I had the same problem at the beginning of this season. If you have a Rochester carb and a single diaphragm fuel pump (same setup as mine) there is an extra hose from the fuel pump to the front of the carb. I believe it's a vent for the fuel pump - take the hose off the nipple in front of the carb and remove the nipple. Either one might be clogged. Mine ws completely clogged and would cause the engine to starve when running under load above about 1900 RPMs.