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Old 27-06-2017, 03:07 PM   #1
Dave
 
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Country: UK
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Boat name: Miss-T
Boat make: Ring 21B
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Slow pickup on merc 200

Looking for advice on an issue I have with an old merc 200hp

Engine is running fine when boat is running with 2 pax onboard and knocking out about 55mph at 6000rpm on a 21p prop. Pick up and response seem fine (other than a bit of prop slip).

However, if I try towing a skier or even the ringo's, the engine seems to struggle to knock out the rpm at the hole shot.

i have tried several props, all with the same result.

fuel lines and primer bulb are all new and no kinks in the line.

Is it worth renewing the fuel pump or am I looking in the wrong direction?
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Old 27-06-2017, 07:50 PM   #2
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Country: UK
Location: Coventry (but from Lee on Solent)
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Does it feel like its missing / spark breaking down under load?

What fuel / oil mix are you running?

Have you tried a smaller pitch? 6k on a 21 sounds about right
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Old 28-06-2017, 07:56 AM   #3
Dave
 
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Country: UK
Location: Scotland
Occupation: Offshore Seismic Surveyor
Interests: Boats of any shape or size
Boat name: Miss-T
Boat make: Ring 21B
Engines: 200 XR2
Cruising area: Loch Earn

Join Date: Feb 2006
Location: Scotland
Posts: 239
Quote:
Originally Posted by The Docta View Post
Does it feel like its missing / spark breaking down under load?

What fuel / oil mix are you running?

Have you tried a smaller pitch? 6k on a 21 sounds about right
No, she seems to be running sound. Certainly sounds 'regular' both on and off load

40:1

21p is the smallest I have tried at the moment but I have tried 21p 5-blade and it does the same thing
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Old 28-06-2017, 10:00 PM   #4
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Country: hampshire
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Boat make: ocke mannerfelt b-23
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Prop selection with my xr2 if I was pulling skier

I used to run a19
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Old 28-06-2017, 10:30 PM   #5
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Country: UK
Location: Coventry (but from Lee on Solent)
Occupation: Sales Director
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Boat make: Extreme 21
Engines: Merc V8
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Join Date: Jul 2005
Location: Coventry (but from Lee on Solent)
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Usually you would lose revs with more blades so it would be harder to spin up a 5 blade 21 than a 3 blade 21. Might be worth trying a 19 if you can get hold of one.

6k with a 21 sounds about right for top end on an old 200 though. Does it take a bit to spin the 21 up?
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Old 29-06-2017, 08:34 AM   #6
Dave
 
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Country: UK
Location: Scotland
Occupation: Offshore Seismic Surveyor
Interests: Boats of any shape or size
Boat name: Miss-T
Boat make: Ring 21B
Engines: 200 XR2
Cruising area: Loch Earn

Join Date: Feb 2006
Location: Scotland
Posts: 239
Currently running with a 3-blade, it's the smallest pitch I have at the moment. Would have to have a rake about to see if I could borrow a 19.

With the 21P, I seem to suffer with a lot of prop slip before it bites when I am running lite but when it's loaded (skiing) it takes time to spin up to full speed
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