250 hpdi loosing power

[Mrmikonline]

I have an 2005 HPDI that seems to be loosing power above 5400 RPMs or so. This happens when I'm trying to trim out the motor and jack plate to get above 70 mph or so. It will surge or almost seems like a miss. It sort of flattens out.
Any ideas?

[kk4iz]

Check your tach. make sure it is right, sounds like you are hitting the rev limiter.

Just my $.02

[matt "boot" baty]

I am so glad that there is someone else out there that is having the same problem that I had. I had a 06 225Hpdi and it did the same exact thing above 5600 rpms. It already had a new powerhead put on it after 39 hours. I took it to several dealers, and all they could tell me was that the plugs were fouled. After about 3 different sets of plugs and still the surging, I decided to trade it for a new boat with a Merc 250XS. Now the Merc is doing the same thing!!!

[5-Salt]

O2 Sensor may be telling EFI to dump in too much fuel - does your fuel burn go up by 2-3GPH or more when it starts missing? I saw mine go up by 3-7gph when it would start missing around 40-4500rpm after running for 60-90mins in wamer water.

I cleaned the O2 sensor only have the problem return. Replaced the sensor and no problem since.

Hope this helps.

[looking4five]

I would see if someone would hook up to it, and check the computer's history. I would be very concerned that you are loosing fuel pressure for one reason, or another. That could cause some much more serious problems down the road. I would suspect a fuel delivery problem (one of the many filters on the HPDI engines). Hope you get it straightened out.

[EJP]

Is there an inline fuel filter? Sounds like the problem I had with my last 250hpdi. I did not have the inline fuel filter, and the fuel system had particles in it. t was causing the injectors to clog. If it's in warranty get it in there, and call yamaha's CS line, they stay on top of the dealer to get it in and out.

[Mrmikonline]

Boat goes into dealer tomorrow... Will let you know