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Message board > Engines > Noisy 50hp Four stroke engine

Message 4 of 4
Posted by member Ian Petrie on Wednesday 30 September 2020

Hi Ken
I am having similar issues with my Yamaha 50 of similar vintage all of a sudden.
A couple of considerations -
Are you using on restricted waterways (in my case the non-tidal Thames) or on the sea?
Does the tick over seem to have dropped and become lumpy now the weather is getting colder (easy to adjust)?.
My outboard doesn't like being asked to perform at low revs (below 1,000rpm) or on tick over for prolonged periods.
These big engines are designed for sustained cruising in open water rather than trolling into locks.
I use the more higher octane fuel in mine plus the occasional 'engineer's decoke' by opening the throttle on wider stretches of the river for a brief time - sometimes seems to work.

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Message 3 of 4
Posted by member Rob on Monday 7 September 2020

Hello Keith
Thanks for your reply.
I will check it all in about 3 days time when I get down to the boat.

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Message 2 of 4
Posted by member Keith Lathwell on Sunday 6 September 2020

more info required. Did it suddenly get noisy? Is it noisy when out of gear as well as when under way? Is the performance impaired? Is the oil level ok? Does it vibrate more than normal? Is it running hot? Is it smoking? Is the noise from the power head or lower down? Give us some clues.
Rgds Keith

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Message 1 of 4
Posted by member Rob on Saturday 5 September 2020

I know this is a Hardy message board but my 50hp four stroke engine has become very noisy.
If anyone has any ideas please let me know.
The engine is a 1999 Mariner Bigfoot four stoke. On my model the power head is made by Yamaha.

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