F250 - The Hull Truth

Art Vrola · 08-11-2008, 06:57 AM

I have an '06 Yamaha F250 purchased new and is just at 100 hours. It performs flawlessly except on two separate occassions three weeks apart. after about 4,000 RPMs the motor started to rev erratically between 5,000 and 6,000 rpms. when I slowed down below 4,000 rpms it corrected itself. On both instances I had to repeat this procedure about 3 times and afterwards if ran fine. Both times I was in the Bay and conditions were similar, no cavitation issues, nothing hung up on my prop and not a spun hub. the first time this happened the racor filter had about 80 hours on it and when I changed it there were no traces of water in the fuel. the second time this happended the new racor filter had less than 15 hours on it. Any adive would be greatly appreciated.

TSA · 08-11-2008, 08:30 AM

had same problem with 2006 f250 at about the same hrs. warranty issue with ECU. yamaha will replace with newer/updated/improved ecu. 200 addl hrs.....no more issues.

Art Vrola · 08-11-2008, 07:17 PM

Thank you Jim for your reply. ECU ????

TSA · 08-11-2008, 08:24 PM

the computer module that tells the engine what to do.....replacing it will also zero out your engine hours, so have the dealer give you a print out of the engine data.

A1 Outboard · 08-12-2008, 03:34 PM

It is possible that the ECU could be the problem by messing up the fuel flow and the timing, but that would be a very rare occurance.

From your description, it sounds like a ventilation problem, either exhaust gases feeding back into the prop blades or from a worn area where the propeller fits into the gearcase cavity, or likely from a strake, transducer, or thru-hull fitting somewhere ahead of and within 17" of the engine centerline.

TSA · 08-13-2008, 06:29 AM

Art:

i think A1 is probably correct in their assessment. when i had my issue, the engine would not run right until i shut it down and restarted which would reboot the computer rectifying the buggy code. however the issue is with early model year 2006 f250s. diagnositics will not show anything wrong with the ECU because it reboots on restart.

Art Vrola · 08-13-2008, 10:51 AM

Jim:
I'm bringing the boat in for 100 service on 8/29. Just got off phone with service mngr. While he is open minded and only knows what I told him, he said it could be something other than ECU unit. Now that you tell me diagnositics will not show anything wrong with the ECU because it reboots on restart, what do I do? I don't want them playing with anything that is working fine. any further suggestions? Thanks again for your follow-up. I strongly doubt that it is a ventilation problem since there have been no modifications to the boat/motor from day one, and the engine is too new to show wear where the prop fits into the gearcase cavity.

A1 Outboard · 08-13-2008, 02:52 PM

Art,

The technician can use the graphing option in the diagnostic software to watch the rpm and any changes in timing, sensors, manifold pressure, etc. There is also a monitoring screen that shows what each sensor is doing at that moment. If there are any error codes, they are stored in the ECU until they are erased by the tech.

Art Vrola · 08-14-2008, 07:04 AM

thank you so much for all of your advice. I really appreciate the time you took to respond. I'm happy to know that the error codes are stored in the ECU.