Sea Rider
Supreme Mariner
- Joined
- Sep 20, 2008
- Messages
- 12,345
Owner swapped a OEM 13 pitch prop for same OEM 11 pitch one. As usual removed old prop, greased well shaft splines and inserted new prop. With nut adjusted tight, prop had a 0.5 mm lateral play. Went for a test at speed, not wot though, sea cond was wavy, windy. Some time after there was a unusual grinding like noise heard rear of OB. So headed to marina.
The prop while sitting on shaft had a excessive play. When prop was removed, there was damage found on rear prop lip and round shaft housing lips. Luckily prop hub nor oil seal were compromised.
When both were compared, the old one had a bronze insert spacer while the newer didn't. Although there was a 0.5 mm play, owner found too late that when prop spins it's pushed inwards hard, that accounts for damage to both mentioned parts seen in pics.
Scenario : The spacer will need to be ordered, when installed there will be a huge gap between shaft housing and rear prop body, if using the old prop should be around 10 mm gap, if going for a new prop about half. Question : As exhaust fumes will exit through gap lessening the total amount which should exit through middle prop, what's going to happen, will prop lose torque, hole shot, or better performance ?
It's seller's entire fault not specifying that a spacer was needed, nor a warning note inside plastic bag saying so. So will ask seller to send in a new prop. BTW 13 pitch prop was factory delivered with OB, was undergoing it's first prop maximization with awful results....
Not Happy Boating
The prop while sitting on shaft had a excessive play. When prop was removed, there was damage found on rear prop lip and round shaft housing lips. Luckily prop hub nor oil seal were compromised.
When both were compared, the old one had a bronze insert spacer while the newer didn't. Although there was a 0.5 mm play, owner found too late that when prop spins it's pushed inwards hard, that accounts for damage to both mentioned parts seen in pics.
Scenario : The spacer will need to be ordered, when installed there will be a huge gap between shaft housing and rear prop body, if using the old prop should be around 10 mm gap, if going for a new prop about half. Question : As exhaust fumes will exit through gap lessening the total amount which should exit through middle prop, what's going to happen, will prop lose torque, hole shot, or better performance ?
It's seller's entire fault not specifying that a spacer was needed, nor a warning note inside plastic bag saying so. So will ask seller to send in a new prop. BTW 13 pitch prop was factory delivered with OB, was undergoing it's first prop maximization with awful results....
Not Happy Boating