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Discussion Starter #1
I have a Pearson 365 with a W40 I am currrently not exceeding 2200rpm when under power but my boat speed is only around 4.8 knots. The question is can I run this engine at higher revs the rated HP is 37 at 3000rpm I have run her up to max revs to see and she will hit 3600rpm.

This boat is new to me and I have sailed her across the Gulf of Mexico from FL to TX but did not use the engine that much but now she is here in TX we will be doing much more motoring.

Any help will be appreciated.

Ed :confused:
S/V Moonlight Mile.
 

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Telstar 28
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43,289 Posts
Sounds like you got a badly matched prop or a fouled prop.
 

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It could be many things. Do you get any smoke while running as fast as you can? If yes, you may have an air delivery problem. If no, yo may have a fuel delivery problem. Have you changed all filters?

It could also be...

a fuel pump problem
injectors
lack of compression (valves, rings, etc)
injector pump
 

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Discussion Starter #5
Little more info for you all.

The injector pump is brand new.
The transmission is brand new.
All filters are new oil and both fuel.
Bottom was clean at last haul out month and half ago and 1000 miles of offshore sailing.
No noticable smoke. (some soot on transom after ten days at sea running engine for about fifty hours charging batteries and propulsion etc)
Replaced oil cooler heat exchanger upon return had one tube leak oil into raw water exhaust discharge.

All temps & pressures nominal.

Max revs in neutral 3800rpm, max revs under load 3600rpm would suggest the prop is of correct size or close, recomended delta is 200 to 250rpm.

Just as a foot note, if you own a W40 and you have an oil cooler heat exchanger normally mounted on the stbd side of the engine check it for zinc there is a small plug at the bottom my old cooler did not have a zinc (I assume it corroded away) but the new unit did have a zinc. see attachments
 

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If she is running smooth, and not making any strange clanking or similar odd noises or vibrating excessively, I don't see why you couldn't raise the cruising engine speed to around 3000 rpm. I figure cruising speed to be 2/3 or 3/4 throttle,around 2800 to 3200 on my universal. 4.8 knots at 60% power seems just about right to me, but maybe an expert would know better. But feel for vibration in the drive train, should be none to very little, with very little requiring investigation at some point. Mostly don't throttle her to the point she smokes, if you cant reach the affore mentioned engine speeds without constant smoke, you need to look at you prop as earlier stated.
 
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