Opti low rpms

**Loxboy1** · 01-22-2018, 05:43 PM

Hey all,

hears the back story. My boat had a 2002 225 opti boat would run 50-55mph turning 5500-5600rpms all day. This motor blew a rod so i replaced the entire unit with another 2002 225 opti. I used the lower from the original motor and prop. Now im only seeing 38-40 mph and 4900-5000rpms max, if i trim super high i can see 5100-5200 but i loose speed and the stern feels very “loose”.

Ive checked the following:

Firing on all cylinders. Checked by disconecting each coil at a time and verifying no change in engine rpm. Also verified by removing the plug to each fuel injector 1 at a time.

Verified 80psi air and 90psi fuel preassures. Also checked schrader valves to make sure fuel and air are not bleeding into other sections of the rails.

i checked linkage going WOT. Only thing i knoticed is the arm on the tps can move maby another 1/16 inch before it completly maxes out.

Motor has brand new high and low preassure pumps installed last week.

When the motor is cold and i fire it up , if i unplug the 2 temp sensors on the head the motor with idol up a little bit and run somewhat smoother, could that be an issue?

everyone is telling me to try different props but for the life of me cant understand if i replaced the motor with the exact same motor and every thing checks out good and im using the prop from the orig motor why am i down rpms and mph.

Any help would be greatly appreciated!! Thankyou

**half fast** · 01-22-2018, 06:29 PM

Try unplugging a coil , make a wot pass . Do all cylinders one at a time . This may help at least determine what cylinder is falling behind . Maybe a reed or coil failing . Hf...

**vnemous** · 01-22-2018, 07:18 PM

are you in break in mode for 120 minutes?

**Loxboy1** · 01-22-2018, 07:31 PM

Originally Posted by vnemous

are you in break in mode for 120 minutes?

Yes, i just replaced the air compressor and did the key on throttle up 5 times to trigger the oil pump to prime the air compressor. But this motor was only getting 5100-5200 before i replaced the aircompressor and fuel pumps so being in breakin mode hasnt changed anything

**Loxboy1** · 01-22-2018, 07:51 PM

OT512770 is the serial number for my motor if it helps with anything

**vnemous** · 01-22-2018, 08:58 PM

If you did the oil pump prime you are probably still in break in. you will only get 75% power till you drive, with a load, for 120 minutes

**Loxboy1** · 01-22-2018, 09:38 PM

I took it out sunday just for a little bit close to the house just to make sure its running okay. Next weekend we are going to the sand bar so ill have over 120mins of run time. Is it 120 of non stop run time? Before i replaced the pumps and compressor i was not in break in mode and was still only getting 5200 max. What would be the next thing to check? Reads?

**flabum1017** · 01-24-2018, 12:48 AM

You bought someone else's bag of nuts..... the break-in has to be done by the book before it goes to full power.... off-hand, I could not tell you the procedure/ RPM - Time schedule........... A scan tool will tell you where you are at

**vnemous** · 01-24-2018, 07:56 AM

Break in must be under load, not just run time.

**Loxboy1** · 01-24-2018, 09:01 AM

Okay this weekend im launching at harbor town and taking the ditch down to haulover, hanging out there for the day then coming back. That trip will have more then 120mins under load.

**Loxboy1** · 01-25-2018, 02:40 PM

Doing some reading in the service manual, i found that if the tps fails it will limit the motor to 4500rpms. And if any of the 3 temp sensors fail it will limit power by 25%. Does any one know how to test the temp sensors?

**Steve Pope** · 01-25-2018, 03:05 PM

Pull the front and check the reeds. These engines are notorious for eating them. Optis don't limit rpm during break in. I have rigged heaps of them and they have all run to max revs during prop testing.Its only the hp engines with the motorola ecu that limits revs.

**Loxboy1** · 01-25-2018, 08:16 PM

What do i do, just remove the intake? What am i looking fore? Will it be obvious?

**mercrazy** · 01-25-2018, 08:30 PM

use a mirror and flashlight to check reeds.
some coils only fail after getting warm.

**Loxboy1** · 01-28-2018, 11:45 PM

I changed the reeds today with chris carson reeds none of the ractory steal reeds were damaged. also replaced the plugs (ngk izfr5g gaped at .031) also found 2 plug wires that had damaged boots so i replaced them. Ran the motor on the hose and really didnt knotice any difference in idol it still kindof sputters hear and there. If i unplug the temp sensors on the heads it will idole up to 800 and run very smooth. With them plugged in the tach shows idol speed at 625 ish. I didnt get to run the boat this weekend. I did drain the racor filter that i have mounted inkine just after the tank and fill it with seafoam to do a little cleaning, bad idea?