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Post by ianali on Feb 4, 2021 12:41:53 GMT
Asking for a mate. He found that his PRM had lost a lot of oil on recent inspection. He thinks(?) that it was leaking from the shaft seal. He also noticed that when he had last filled it, prior to doing a few hundred mile cruise, that he had only screwed the filler cap on finger tight. Now, after refilling and doing the cap up he can see no leakage. He has ran the boat for a couple of hundred miles in gear, whilst tied up.. no sign of oil leaking. Any ideas?
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Deleted
Deleted Member
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Post by Deleted on Feb 4, 2021 12:55:07 GMT
Suspect loose filler cap.
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Post by ianali on Feb 4, 2021 14:35:53 GMT
Suspect loose filler cap. That’s what I suggested. He is adamant though that all is clean and dry around the cap and it was leaking near the seal. I can’t go look as he’s way up in snowy Scotland with it. |
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Post by Telemachus on Feb 4, 2021 16:02:32 GMT
PRM 150 gearboxes can leak oil from the seal where the shaft for the gear selector arm passes through the casing. There is an o ring thingy. If the gear lever travel is misadjusted so that the lever is being pushed hard against its end stop, this can cause seal failure. When you operate the morse control, the selector arm on the box should not quite reach full travel.
Also there is usually a heat exchanger between the gearbox oil and the engine coolant, so I’d be checking for signs of oil in the engine cooling water.
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Post by ianali on Feb 4, 2021 16:22:00 GMT
PRM 150 gearboxes can leak oil from the seal where the shaft for the gear selector arm passes through the casing. There is an o ring thingy. If the gear lever travel is misadjusted so that the lever is being pushed hard against its end stop, this can cause seal failure. When you operate the morse control, the selector arm on the box should not quite reach full travel. Also there is usually a heat exchanger between the gearbox oil and the engine coolant, so I’d be checking for signs of oil in the engine cooling water. Thanks for reply. The thing is that it was loosing a lot of oil until he refilled and tightened the filler cap/bolt. As I said, then after a good couple of hours or running in gear(but tied up) he can see no sign of leakage. Odd I know. |
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Post by Isambard Kingdom Brunel on Feb 4, 2021 16:23:35 GMT
A loose dip stick/filler will leak oil. The gears throw oil at the filler when the engine is running. A hot gearbox will not show much of a leak, the oil runs off very well when its warm.
There are lip seals on the input shaft in the drive plate housing and on the output shaft before the flex coupling, a square section o ring on the gear selector spindle and gaskets between the two halves of the case and on the oil pump on the back.
There are Dowty seals on the filler and the drain plug.
There should be an oil cooler in the cooling water circuit connected by two flexible hoses. It is not unknown for the cooler to leak oil into the cooling water, it will show in the radiator cap thingy floating on the water, milky looking if this has occurred. Unlikely but possible.
If the gearbox is not now losing oil, I would suggest that it has simply escaped from the filler plug.
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Post by ianali on Feb 4, 2021 16:53:31 GMT
A loose dip stick/filler will leak oil. The gears throw oil at the filler when the engine is running. A hot gearbox will not show much of a leak, the oil runs off very well when its warm. There are lip seals on the input shaft in the drive plate housing and on the output shaft before the flex coupling, a square section o ring on the gear selector spindle and gaskets between the two halves of the case and on the oil pump on the back. There are Dowty seals on the filler and the drain plug. There should be an oil cooler in the cooling water circuit connected by two flexible hoses. It is not unknown for the cooler to leak oil into the cooling water, it will show in the radiator cap thingy floating on the water, milky looking if this has occurred. Unlikely but possible. If the gearbox is not now losing oil, I would suggest that it has simply escaped from the filler plug. Yep I agree.. hard to see any other conclusion isn’t it. Time will tell I guess. Thanks for replying. |
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Post by quaysider on Feb 4, 2021 17:34:41 GMT
I'm with the lose cap - mine did the same... hadn't looked for a few weeks then noticed god knows how much on the floor... emptied it out, refilled and carefully tightened both sump and filler and it's not lost a drop since.
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