RPM's drop at 3100-3200

[rcmeyer]

I have a 1991 26ft Regal w a 454 7.4L Mericruiser that i just picked up about a month ago. Ran it hard 2 weekends in a row and on the 3rd week, when I open it up to get up on plane, the rpm's drop REALLY FAST back down to 1800-1900. It keeps doing this. If I rev it slow I can get the rpm's up to about 3100...tops.
Mechanic thought it may be water in the fuel and he was right. When he emptied the separater, there was plenty of water in it. So he poured the gas back in the filter, put it back on and ran it again. Same thing. We replaced plugs, wires, cleaned rotator cap and put in some full throttle fuel treatment. Same thing. He did a compression test and cylinder 5 was hitting at 80psi compared to the other 7 @ 140psi. One cylinder w low compression isn't going to cause this is it???

Thanks,

Ryan

 

[Don S]

Re: RPM's drop at 3100-3200

So he poured the gas back in the filter, put it back on and ran it again. Same thing.

Just emptyiing a filter and sticking it back on is not going to get the water out of the carb.
You need to get the water out of the tank, put on a new filter after cleaning the fuel lines from the tank, and removing, disassembling, and cleaning and rebuilding the carb. Then it will probably work.
Since all he did was dump the old fuel back in a already contaminated filter, nothing was gained, except money moving from your pocket to his.