horse power surge

josh_2562

Seaman
Joined
Jun 7, 2007
Messages
60
I have a 1992 merc 100hp. the other day i took the boat out. when I hold it wot it goes to about 5100rpms then it will bog down to about 4800rpms then go back up some time it won't go past 4800rpms. what could cause this. I changed my fuel filters blew all the lines out with air. took the carbs apart and they are all clean.and the tank is clean. and rebuild the fuel pump. could this have some thing to do with the timeing. tHANKS FOR ANY HELP
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: horse power surge

That is a classic symptom of a weak fuel pump. Since you rebuilt it, that should have fixed it. Try pumping the fuel primer bulb while at WOT. If that clear it up, check the lines for leaks and the fuel pump pulse lines for leaks. If that doesn't help, perhaps you are fouling a plug and then it clear up. Check the plugs for proper color and absense of water.
 
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