1999 500 HP carb lost rpms???
 

anyone have any ideas as to why i would lose rpms, or what to check next? bought boat last year, early in season I was running 5100 rpms approx. on a 36 outlaw and 25 p mirage plus props 73mph on gps. put bad tank of gas in it and could not get it to run more than 4900 and 69 mph. had valve springs done over the winter and valve job, plugs wires etc. now i run 4800 and the best i can get out of it is 67 mph, mostly runs between 65-66 all gps. when i first got the boat back everything ran smooth, idles great fires right up. had loose plug wire on port engine last weekend, now both engines start a little hard, backfire until they warm up. port engine runs slow rpm wise until it is fully warm maybe 15 min or so. and then it is fine.

going to have checked

butterfly in port 4 barrel carb
fuel pressure in both

ran 25p labbed mirage plus today, old props today 4700 @ 66.7 mph new labbed today 4800 @ 67.0 mph pretty close to the same

i need my speed back, what else should i check?? any typical problems with this engine??

scott

rocky, please no smart a$$ coments :rolleyes: