I own a 2004 Hydra-Sports 23' Bay Bolt with a 2004 Yamaha F225 4-stroke mounted on a jack plate. The boat was purchased from a dealership as a dealer-demo type in May of 2007 with 140 hours. Everything on the boat was rigged at the factory and by an authorized Hydra-Sports/Yamaha dealership. I currently have 220 hours on the boat.
The boat is equipped with a water pressure guage which typically would max out at a mere 11-13 psi with WOT, although steady, regardless of jackplate setting between 1" and 4". The jack plate maxes out at 6" but I never run the motor that high unless idling through shallow water. Recently, around 200 hours, I noticed that the pressure was beginning to drop down to 7 or 8 psi at WOT, so I figured it was time to get the 200 hour service and replace the water cooling system parts (impellor, thermostats, etc.), and everything else recommended by the dealer. Upon getting the boat back I noticed some alarming results with the water pressure again.
I tried several tests at various jack plate settings with the results being the same at each jack plate setting unless I get too high on the plate i.e., above 4 inches (therefore 4 inches is the highest setting for my use.) At idle I have 0 psi, (normal I'm told), at 3000 RPM water pressure peaks at 15 psi (higher than ever before since purchase), at 4000 rpm the pressure drops to 11 psi, and at WOT the pressure drops to 7 or 8 psi! Even more strange, if I back the RPM down to 3000 from WOT say 5500 RPM, the pressure never recovers until I come to a complete stop and go through the whole process again.
Another interesting point, with the motor out of gear, I can increase the RPM and get an increase in pressure that holds steady as advertised, exactly how it should be when running, around 15-20 psi or so.
After all this, I took the boat back to the dealership and so far they have tried nearly everything with the same results. They then involved Yamaha who claims that this is a normal result of using an engine on a jack plate and also claim it is probably mounted too high. All in all, they said that this is normal operation and if there is no overheat condition, than all this is nothing to worry about. They put out on their website that the minimum WOT setting is 11 psi. I had a tech rep tell me that 7 psi is the limit. This motor has never had an overheat condition (as proven by the lack of codes shown when hooked to the computer at the dealership), and runs great except for the lack of pressure. I'm highly concerned with all these uncertainties regarding water pressure and do not want to overheat the motor. As for being mounted too high, it's as low as it can be on the plate and at the lowest setting has the exact same performance as it does up to 4 inches higher, I don't buy that answer.
So far Yamaha is not willing to consider this a warranty problem and my dealer is stuck with 9 hours of labor for nothing. I'm still trying to contact Yamaha myself to see what they can do.
Standing by for any assistance
Sam
The boat is equipped with a water pressure guage which typically would max out at a mere 11-13 psi with WOT, although steady, regardless of jackplate setting between 1" and 4". The jack plate maxes out at 6" but I never run the motor that high unless idling through shallow water. Recently, around 200 hours, I noticed that the pressure was beginning to drop down to 7 or 8 psi at WOT, so I figured it was time to get the 200 hour service and replace the water cooling system parts (impellor, thermostats, etc.), and everything else recommended by the dealer. Upon getting the boat back I noticed some alarming results with the water pressure again.
I tried several tests at various jack plate settings with the results being the same at each jack plate setting unless I get too high on the plate i.e., above 4 inches (therefore 4 inches is the highest setting for my use.) At idle I have 0 psi, (normal I'm told), at 3000 RPM water pressure peaks at 15 psi (higher than ever before since purchase), at 4000 rpm the pressure drops to 11 psi, and at WOT the pressure drops to 7 or 8 psi! Even more strange, if I back the RPM down to 3000 from WOT say 5500 RPM, the pressure never recovers until I come to a complete stop and go through the whole process again.
Another interesting point, with the motor out of gear, I can increase the RPM and get an increase in pressure that holds steady as advertised, exactly how it should be when running, around 15-20 psi or so.
After all this, I took the boat back to the dealership and so far they have tried nearly everything with the same results. They then involved Yamaha who claims that this is a normal result of using an engine on a jack plate and also claim it is probably mounted too high. All in all, they said that this is normal operation and if there is no overheat condition, than all this is nothing to worry about. They put out on their website that the minimum WOT setting is 11 psi. I had a tech rep tell me that 7 psi is the limit. This motor has never had an overheat condition (as proven by the lack of codes shown when hooked to the computer at the dealership), and runs great except for the lack of pressure. I'm highly concerned with all these uncertainties regarding water pressure and do not want to overheat the motor. As for being mounted too high, it's as low as it can be on the plate and at the lowest setting has the exact same performance as it does up to 4 inches higher, I don't buy that answer.
So far Yamaha is not willing to consider this a warranty problem and my dealer is stuck with 9 hours of labor for nothing. I'm still trying to contact Yamaha myself to see what they can do.
Standing by for any assistance
Sam