Logo

Yamaha Z250TURB , 2002 help needed

steveus

Member
You guys have been a huge help to me in the past on a little 15 hp Mariner. Was able to do the work that some of you suggested myself, and haven't had a problem since. This one will be out of my league.

My son came about a 23' fiberglass boat with this Yamaha 250 on it. Owner had just gotten a new rig and wanted this gone. Told son that he
had bought the motor new, had it installed on boat, and had had it serviced by dealer once a year. Sitting on galv. trailer. Used in salt water.
Let a Yamaha dealer check compression, said perfect. Motor runs very well for a little while, then starts to get hot, seems to go into limp mode if it has such a thing. Replaced water pump impeller, have not run yet, but worried that old one did not look bad. I'm thinking it's not getting enough water, maybe corrosion.

Mfg. date 07/2002, other info is: Z250 turb, 60V U 10002 HPDI

Any thoughts? Thanks much. We are on the GA coast.

Steve
 
Forgot to add, engine runs perfect for several laps around 250 acre lake, then acts like stated in above post. Then, you can switch if off, wait about a minute, and she runs fine again for same amount of time, the acts like it's getting hot again.
Also, mfg. date is 07/2002, but Yamaha code calls it a 2003.

Thanks in advance for any comments.

Steve
 
Start with an inspection of the pressure relief valve and the thermostats.

Put a pressure gauge on garden hose inlet port to monitor water pressure while the motor is running. Should be a minimum of 11 psi at WOT.

The term limp mode is not a Yamaha term. The motor does have self protection in the event of low oil quantity or over temperature in which case the RPM will be limited to about 2500 RPM. Having a Yamaha tachometer installed will tell the operator the reason for the warning horn sounding. What type of tachometer is installed? If a Yam, what is it doing with the alarm activates?
 
I think it could be the dirt in the Vapor Seperator Tank clogging the screen PBRMAN mentions. Not familiar with that specific engine but often they get crud from ethanol gas in the VST tank that houses the fuel pump. As the fuel is flowing and and being drawn into the fuel pump the engine is vibrating and stirring up all that crud that gets clogged in the VST screen that feeds the fuel pump. Shut it down, fuel flow stops, crud falls back the bottom of the VST tank. Fire it up again and the crud starts clogging the filter again until you get fuel starvation again. It will repeat itself until you clean the screen and any crud sitting on the bottom of the VST tank that gets vibrated and up from the bottom and sucked into the filter screen again.
 
Want to thank everyone for the help, much appreciated! My son sold the rig, win-win for both parties, appears that problem was as suggested, VST filter. Everyone happy. Thanks, Steve
 
Back
Top