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.

thanks for the input guys!!

Talked with the servicing dealer yesterday and they looked up the work order. Looks like the fuel filter they put on was not a merc...it is some aftermarket thing, i cant recal the name right now. They hope it doesnt flow the fuel that i need and its the source of my rpm loss. They gave me a merc filter which i will install later today. If the weather holds we should be out on the lake tomorrow. I will keep my fingers crossed and post the findings out.
Thanks for all the help here, it is very much apreciated.

Hey guys.. A little info....

Changed out the fuel filter but didnt check the plugs on Sunday and went out for a ride.....

The rpm's were still down......I will check the spark plugs.

Another interesting note- the dealer said they installed an extra litre of oil then what the manual called for......could this also be part of the problem??

Nah a liter will not hurt!
http://budzmotorsports.com/BMS_Photo..._IMG_05068.jpg

Take the plugs out and do a compression check. You may have a damaged engine.

Just an update as to my findings....
-2 liters of oil too much from dealer oil change along with incorrect fuel filter.....
-engine overreved and put into guardian mode
-crankshaft position sensor code activated-upon start up 350 rpm
-camshaft position sensor code activated- ypon start up also

-Cleared all codes, drained oil to proper level and seems to run a constant 4900 rpm, cannot trim anymore or the boat will loose mph.

Thankx to all that have help with their input, it was greatly appreciated!!

Mike