WOT RPM and Top Speed Loss

[Masher44]

Hi All, Just encountered my first problem with my 18 month old boat. It has a 2003 525 efi with an XR Drive, 28" 4 blade prop. Boat has ran great until yesterday. Was out on the lake and running great at about 5200 rpm and 78-79 mph. Stopped and took a swim then got in and ran back up the lake and only could manage about 4800 rpm and about 68-69 mph. Took the boat back today and ran it again with the same results, despite putting a new prop on and adding gasoline treatments with the hope of it being water in the fuel. I am at a loss, props are fine, didnt hit anything, no vibrations, hull is OK, bilge works fine. The boat comes out of the water fine it is just at top end it wont get up and kick it up the last 300rpms. Boat has 60 hours on it and I change the fluids constantly. I am not sure if it could be a fuel filter/obstruction in the lines?, an impeller issue? bad gas?, Out drive malfunction ( I just had AMSoil put in the outdrive) Any help would be very greatly appreciated. Thanks Jim

 

[f_inscreenname]

Re: WOT RPM and Top Speed Loss

Pull and check your spark plugs and wires. See if they don't tell you something.

 

[Masher44]

Re: WOT RPM and Top Speed Loss

What would I potentially be looking for on the plugs or wires? Thanks Jim

 

[Masher44]

Re: WOT RPM and Top Speed Loss

Update: Went out today. Checked plugs, added 4 cans of dry gas, octane boost and 30 gals of 93 octane. Ran for about an hour straight to get new fuel through. No change... even a little worse. Can definetly hear that the boat just doesnt want to take gas above 4500. It sputters at about 4400 and only gets to about 65 mph. Also when I back off to slowly it seems to jump back up to a good clip like something is blocking the fuel when I open her up. Any additional thought would be greatly appreciated. I also replaced the fuel filter prior to my voyage. Should I run it more to try to get the fuel through? I used about 15-20 gals. today. Will this do any damage to the motor? Thanks Again for any insight. Jim

 

[tommays]

Re: WOT RPM and Top Speed Loss

i would recomend that you DO NOT USE DRY GAS it makes it inpossable for the water sepator to work correctly because the water is now mixed with chemical that will pass it by the filter<br /><br />tommays

 

[Masher44]

Re: WOT RPM and Top Speed Loss

Tommays, What would you recommend to use? Also, went out today and sane results. Any additional thoughts? Thanks for the advice!

 

[tommays]

Re: WOT RPM and Top Speed Loss

check the sepator for water and change it often<br /><br />any teck has to use there experance to listen to the boat running and use what they have learned to try the most likely cause based on similar problems<br /><br />you motor has so much electroincs that with out fuel pressure readings and a code reader your in the dark as to the real cause<br /><br />i dont no if the amsoil is rated for outdrive use???<br /><br /><br />tommays