AGENT 37
Petty Officer 1st Class
- Joined
- Mar 2, 2007
- Messages
- 319
1998 Honda BF90A
It started as a 20" shaft motor which was too short for the transom on the boat.
I removed the original Mercury-built lower unit, swapped out the upper shift shaft, extended the water tube, installed studs and a spacer and hooked up a used "newer" Honda-built 25" lower unit.
I used it with no issues for one season..... about 120 hours.
I am a smooth shifting operator...... no gear grinding.
Pulling up to an Alaskan beach to drop off a deer hunter, I shift into reverse and apply throttle to time the stop and back down as he jumps off of the bow. As I increase the throttle to about 2000 RPM the gears start grinding and I lose all thrust just in time to have the boat coast up onto the beach. I shut the motor off and jumped out to keep the boat from going too far onto the beach. The boat got turned sideways on the beach and the wave action snapped the skeg off with side ward pressure. Got the boat off of the beach and it shifted into gear but kicked out with throttle again. I had the boat out two more times and the condition worsened. Now it grinds just barely trying to clutch into reverse and does not engage. Forward has no issues.
Cable adjustment is normal. It was not out of adjustment. Prop shaft, drive shaft and shift shaft are all straight. I dropped the lower unit and drained the oil. There was water but no rust, there were also no metal particles present. I flushed out the case with kerosene and when it was sealed it leaked out around the water pump housing.
I applied 10-12 psi with air and I can hear it coming out there and nowhere else, so I suspect the failed seals on the drive shaft to be the water intrusion culprit.
Questions:
My repair manual shows no stainless pump-liner-insert on the BF90/75 and no o-ring...... both of which I found on my unit. My unit's config. resembles the BF115/130 depiction in the manual. Is this normal for the newer BF90-non-fuel-injected lower units like what I have? Or does it sound like a BF115/130 unit?
Trying to turn the shift shaft on the lower unit.... it turns further in the direction to engage the forward gear and stays in that detent with out any pressure applied than it does in the reverse gear direction. The reverse also barely engages and disengages if the shift shaft is not physically held turned in that direction. Is this normal and if not, what would the likely cause be?
It started as a 20" shaft motor which was too short for the transom on the boat.
I removed the original Mercury-built lower unit, swapped out the upper shift shaft, extended the water tube, installed studs and a spacer and hooked up a used "newer" Honda-built 25" lower unit.
I used it with no issues for one season..... about 120 hours.
I am a smooth shifting operator...... no gear grinding.
Pulling up to an Alaskan beach to drop off a deer hunter, I shift into reverse and apply throttle to time the stop and back down as he jumps off of the bow. As I increase the throttle to about 2000 RPM the gears start grinding and I lose all thrust just in time to have the boat coast up onto the beach. I shut the motor off and jumped out to keep the boat from going too far onto the beach. The boat got turned sideways on the beach and the wave action snapped the skeg off with side ward pressure. Got the boat off of the beach and it shifted into gear but kicked out with throttle again. I had the boat out two more times and the condition worsened. Now it grinds just barely trying to clutch into reverse and does not engage. Forward has no issues.
Cable adjustment is normal. It was not out of adjustment. Prop shaft, drive shaft and shift shaft are all straight. I dropped the lower unit and drained the oil. There was water but no rust, there were also no metal particles present. I flushed out the case with kerosene and when it was sealed it leaked out around the water pump housing.
I applied 10-12 psi with air and I can hear it coming out there and nowhere else, so I suspect the failed seals on the drive shaft to be the water intrusion culprit.
Questions:
My repair manual shows no stainless pump-liner-insert on the BF90/75 and no o-ring...... both of which I found on my unit. My unit's config. resembles the BF115/130 depiction in the manual. Is this normal for the newer BF90-non-fuel-injected lower units like what I have? Or does it sound like a BF115/130 unit?
Trying to turn the shift shaft on the lower unit.... it turns further in the direction to engage the forward gear and stays in that detent with out any pressure applied than it does in the reverse gear direction. The reverse also barely engages and disengages if the shift shaft is not physically held turned in that direction. Is this normal and if not, what would the likely cause be?
