2005 225 Pro XS Optimax

[brucebruce]

1.) 1B118088
2.) 2005 Mercury 225 Pro XS Optimax on a 2005 Ranger Z20
3.) Mercury Tempest Plus 25P
4.) 3,800 to 4,000 RPM's in the water (5,500 - 6,000 RPM's in a run tank)
6.) SmartCraft

I am at my wits end with my motor. The boat basically plows water for several minutes at anywhere from 2,000 RPMs to 2,500 RPMs before finally getting enough power to jump up on plane. It will then only max out at the 3,800 to 4,000 RPM range. I have now taken it to my mechanic twice but he has never ran the boat in a lake nor a river. Below is a list of what has been done to date.

1.) Fuel Tested (mechanic said the fuel was good.....I only run non-ethanol in 91 or 93 octane)
2.) Spark Tested (mechanic said spark was good......new plugs installed in Feb using NGK IZFR6J; .033" Gap)
3.) VST Pulled and Checked (mechanic said fuel pressure and air pressure was good)
4.) New Fuel Filter Installed
5.) Fuel Line from Primer Bulb to Motor was Replaced
6.) All Injectors Pulled and Sent Out to RX Injector [the report i was given stated (a. - Injector p/n 37001 - static flow was 660 across all) (b. Injector p/n 884595-1 - static flow was 2,700 across all) (leak test on all was a pass and the spray pattern on all was good)]
7.) Compression Check Done (mechanic said compression was good on all cylinders)

I appreciate any help/suggestions that could be thrown my way.

[JOE54]

has it ever ran right , reeds inspected , cyl drop test in lake needs to be done , 87 oct fuel in pro xs mtrs , plug gap .043-.044 , drop test will determine which cyls arent working under load

[brucebruce]

The RPM's have always been low. I do not believe the reeds were inspected and know for a fact that a cylinder drop test was not done. The plugs in my motor have a gap of 0.33, should they have a gap of .043-.044?

Thanks for the recommendations on the reeds and drop test. I will most likely be taking it to another mechanic Friday around Lake Conroe.

[irbf30]

FAQ says 2007 and under should be gapped .032-.033. 2007 and up should be .042-.044. Joe, which is right? You or FAQ.

[JOE54]

if its got gray direct injectors .043-.044

[blacknitro]

My old 225 Optimax, that failed some months back, did the same thing for years. Pulling the failed powerhead, found the exhaust relief holes were plugged. It ran great at high rpms until a wrist pin came out of a piston at 1400-ish hours.

[EuropeanAM]

if its got gray direct injectors .043-.044

That's actually when Multi-Strike coils are used. Earliest V6 3L ProXS powerheads had external coil drivers with a single-strike ignition (.032-.033" on those plugs).

Have you TRIED a 24P or 23P prop just to see if the engine CAN spin up to RPM's? That might help us to know if we may possibly be looking at something a little deeper (adapter plate gasket and/or rotated sleeves).

This engine vintage did see some sleeve rotation problems.