Problems with 280

[CraigR25]

I have a 2003 Merc 280 short shaft. I had Performance Plus Marine do the breakin for the motor. When I got the motor it ran fine the first time now the motor feels like it is falling in and out of the breakin mode. I ran it earlier today and the motor only wanted to turn 2000 rpms and then all of a sudden it let loose but only wanted to turn 6500 rpms. Only twice I hit over 6500 rpms. Any advice would be appreciated.

Thanks,
Craig

[spanky2002]

what size prop are you running? i have a friend who had a 300 drag on a 2002 and it would only turn 6600 with a 32 cleaver. he had to run a 26 to get his desired rpm. if your prop is no bigger than a 28 i would think something is wrong. my promax can swing a 28 7k+.

[CraigR25]

I am turning a 28 chopper 2 bullet cut on a stroker boat. Everyone else with this setup is running the same and turning 7800 rpms.

[myron]

you might check the spark plugs since you just came off of break in

[OLD BOB]

I have a 2002 280ss on a Stroker also. I am at 2000 ft. el. I have been looking for a smaller pitch because I can only pull a 26 Trophy to 6800 rpm. I tried a 26 et and could only get 7000 out of that prop. If you find something that works good, please let me know.
Thanks, Robert

[pirogue]

I would definetly check plugs. I know someone who fouls plugs every time he takes the boat out(still in break-in.) I don't know why the plugs foul but on aver. it is 2-3 per day.

You may want to check the timing sensor by the flywheel, it suppose to have a .040 gap between it and the timing plate.

I think there suppose to be a .011 gap in the butterfly at idle also.

From 1st impression of the motor they seem to be real finiky.

Don't know just trying to help, good luck!!:)

[MIKE'S MIRAGE]

HAS THE MOTOR BEEN HOOKED UP TO THE DDT YET. IF YOU HAVE A SENSOR FAULT, GUARDIAN WILL KICK IN AND REDUCE POWER. KEEP US POSTED. MIKE

[jerry]

THERE IS SOME WEIRD BREAK IN THING ON THOSE MOTORS . CALL MERCURY TECH ON IT , MOST DEALERS DONT KNOW IT . IF YOU SHIFT THE SHIFTER SOMETHING LIKE 4 TIMES IN 10 SECONDS IT PUTS THE MOTOR BACK INTO BREAKIN . MY FRIEND JUST SENT HIS POWERHEAD TO MERCURY TO GET CHECKED OUT BECAUSE OF THE SAMETHING. NO MATTER WHAT PROP IT WOULDNT GO OVER 6600 RPMS !!!!!!!!!!!!!!!!!!

[Euroski]

2 suggestions, 1- change the plugs to NGK's BR8HS, 2- you should be running synthetic oil by now. My 280 had all kind of problems fouling plugs until the breakin mode when off. I did run Merc plus oil until it got past the breakin. Since then... no problems at all.