Tooluser
Flǎneur
I'm looking at an E38 that is quite nice in many aspects. It has the original rigging and original main, which, not being an antique collector 
I'll probably replace. But the thing that's giving me pause is the engine.
Several of the classic repairs have been performed; water pump, bigger heat exchanger, etc. But it is underperforming to a degree that warrants investigation. Here are the salient pieces I can come up with. I'd love it if y'all can tell me what's wrong or help me think through it as I'm eager to join the club.
- Universal 5432 factory top RPM 2800
- In neutral, runs at 2800 no problem
- In gear, tops out at ~2200 (was 2000 until I cleaned a marine sanctuary off the prop)
- Original prop replaced w/ Flex-O-Fold (17" x unknown pitch) ~2 yrs ago.
- While surveying, oil filter exploded, spraying oil. Autopsy revealed rust on the (automotive) filter had weakened it.
- Once replaced, oil pressure stayed within normal limits, behaved fine.
- Water pump replaced 'recently' [Getting exact date]
- Boat has been sitting largely unused (~30 hrs) since last filter change (Nov 2021)
My analysis:
Engine compartment is clean and dry, so it's unclear what could have caused the corrosion. The pump was a recent replacement. If it sprayed salt water on the oil filter, perhaps that's the cause? Alternatively, something much more dire.
I talked to a prop mechanic who said that a 600 rpm deficit is nothing to sneeze at and will be bad for the engine. He suggested the boat may be overpropped, which Flex-O-Fold seems to be notorious for based on other forums. I'm awaiting prop measurements.
In the absence of that, how can I get my head around this?
Owner seems perfectly nice and honest, but I don't expect him to be omniscient.
I'll probably replace. But the thing that's giving me pause is the engine.Several of the classic repairs have been performed; water pump, bigger heat exchanger, etc. But it is underperforming to a degree that warrants investigation. Here are the salient pieces I can come up with. I'd love it if y'all can tell me what's wrong or help me think through it as I'm eager to join the club.
- Universal 5432 factory top RPM 2800
- In neutral, runs at 2800 no problem
- In gear, tops out at ~2200 (was 2000 until I cleaned a marine sanctuary off the prop)
- Original prop replaced w/ Flex-O-Fold (17" x unknown pitch) ~2 yrs ago.
- While surveying, oil filter exploded, spraying oil. Autopsy revealed rust on the (automotive) filter had weakened it.
- Once replaced, oil pressure stayed within normal limits, behaved fine.
- Water pump replaced 'recently' [Getting exact date]
- Boat has been sitting largely unused (~30 hrs) since last filter change (Nov 2021)
My analysis:
Engine compartment is clean and dry, so it's unclear what could have caused the corrosion. The pump was a recent replacement. If it sprayed salt water on the oil filter, perhaps that's the cause? Alternatively, something much more dire.
I talked to a prop mechanic who said that a 600 rpm deficit is nothing to sneeze at and will be bad for the engine. He suggested the boat may be overpropped, which Flex-O-Fold seems to be notorious for based on other forums. I'm awaiting prop measurements.
In the absence of that, how can I get my head around this?
Owner seems perfectly nice and honest, but I don't expect him to be omniscient.
)