496 ho lost RPM
 

Help please!!!!!!!!!!!!!!!
Hey guys I need to pick your brains!!!!!
I recently had the fluids changed in my 280 silencer incuding engine, drive, and fuel filter, water separater. The oil was replaced with Royal Purple synthetic, the filters all merc.
After the service when we were out in the boat my w.o.t. dropped by 4-500 RPM...:eek: it didnt matter what I did I could not get the revs back....even lifting the hatch a bit only got me about 100 rpm.:(
I asked the mechanic if they screwed around with anything and the answer was no.
The only other difference was the air was about 10 degrees warmer.....I dont think that would make the difference.
Would somebody have any ideas?????

Inline filter on backwards? The only things changed that I would expect to effect WOT would be the fuel filters. Was anything done with the spark arrestor? Did they kink a fuel line?

Check the plug wires to make sure one was not accidently pulled off. The number 2 wire right next to the fuel/water separating filter would be the first one I would check.

Good idea check you plug wires. Also check for wot at throttle blade with engine off.

Thanks for the input guys, I appreciate the help. If a plug wire was off wouldnt idle be a little rough- noticable??
-nothing done to the spark arrester.

Once the rain stops I will check these items out...again thanks.

On my boat, I could not tell anything was wrong at idle when I had a plug wire fall off. I noticed it once I tried to plane the boat (a little sluggish) and run at WOT (down 400 RPM).

Take it back to the servicing dealer and have them hook up the scan tool and read for any codes or reduced power levels that may be present.

Best Regards,
Ray @ Raylar

Thanks guys...Ray I sure would love to have one of your engine packages.......you could advertise on my boat!!:ernaehrung004:

Checking the firing order while looking for loose wires wouldn't hurt either.

Exactly. Don't spend your time guessing.