bigredbaja

Need some help here this is my first 496 Mag I have always had 502's in the past. Put the new boat (03 288 Sunsation MCOB) in the water this weekend and boat ran great. Prior to the purchase I had a full survey, compression & Leak down and had the drive pulled for inspection. All numbers came back well withing the parameters posted by Raylar on an earlier post. also did a sea trial and run the bot all the way to WOT with noo issues. Boat has 223 hours. I was able to open it up a few times yesterday and running a 24p Bravo 1 hit 4400rpm and 60 on the speedo (not GPS) I know to expect about 62 out of the boat, I was not trimmed to the sweetspot so I think the other 400 or so rpm will come. also should mention i had four adults and abotu 80 gallons of fuel on board. Question is at about 3800 - 4400 rpm i can hear a loud popping nosie from the exhaust, (sounds like port side) sounds last plastic flapping at high speed or a series of small firecrackers. The engine pulls strong at all rpm's and the tach is steady so I am having a hard time with the idea that its missing out. Anyone have any ideas??

Knot 4 Me

Given the fact that you just had a compression test done and you are down 400 RPM, I would say they may have cracked a plug when removing/reinstalling them.

bigredbaja

Thanks....that or a loose or bad plug wire seems to be the general consensus I will pick up a set and get them replaced.

Knot 4 Me

It is very easy to not get a wire reseated properly too so one may have fallen off. I had this happen on my 496. Number 2 wire was laying in the bilge.

bigredbaja

Replaced the plugs today and I either had a bad plug or loose plug wire the boat ran great. Trimmed out 4650-4700 and 65 on the wish-o-meter. It ran perfect all day long!

hp500efi

Great news!!