Matthew A.
Petty Officer 1st Class
- Joined
- Jan 24, 2006
- Messages
- 232
I recently began to use a rubber made 100 gal tub to rinse the motor after a day on the water instead of using the muffs. I did so for two reasons. One to save water and to make rinsing the motor a much quieter event.
However, the last two trips out I noticed a drop in water pressure at higher speeds. What once read 10 to 12 psi now reads 7 or 8 psi. at 3000 rpms and above. The psi will come up to around 10 or 12 psi for a few moments when going from a low rpm of below 2000 and quickly throttling upwards to 4000 rpm or higher. However, the psi then begins to settle to the 7 or 8 psi and remains painted there until you lower the rpms again. The motor is not running any warmer then it normally does, even after running at high speeds or low speeds for long periods of time. Flow out the pee holes is excellent.
I am wondering if perhaps the impeller is getting damaged from the small amount of residual oil and fuel that gets mixed with the water. Or, could the extra lubrication due to the very slight fuel oil mix in the water be doing something to lessen flow restriction or [for all you pipe fitters out there] lessening the "friction loss" thru the block via smoother action of the pressure bypass components, less restrictive corrosion perhaps or....?
The impeller and seals have around 100 to 150 hours of use. However, we have only rinsed the motor using the tub method 3 times. Each time rinsing the motor for 20 minutes or so. Water temp of water in tub after rinsing goes from 65 degrees at the start and warms to 80 to 85 degrees when rinse in complete.
However, the last two trips out I noticed a drop in water pressure at higher speeds. What once read 10 to 12 psi now reads 7 or 8 psi. at 3000 rpms and above. The psi will come up to around 10 or 12 psi for a few moments when going from a low rpm of below 2000 and quickly throttling upwards to 4000 rpm or higher. However, the psi then begins to settle to the 7 or 8 psi and remains painted there until you lower the rpms again. The motor is not running any warmer then it normally does, even after running at high speeds or low speeds for long periods of time. Flow out the pee holes is excellent.
I am wondering if perhaps the impeller is getting damaged from the small amount of residual oil and fuel that gets mixed with the water. Or, could the extra lubrication due to the very slight fuel oil mix in the water be doing something to lessen flow restriction or [for all you pipe fitters out there] lessening the "friction loss" thru the block via smoother action of the pressure bypass components, less restrictive corrosion perhaps or....?
The impeller and seals have around 100 to 150 hours of use. However, we have only rinsed the motor using the tub method 3 times. Each time rinsing the motor for 20 minutes or so. Water temp of water in tub after rinsing goes from 65 degrees at the start and warms to 80 to 85 degrees when rinse in complete.
