sorry prop size again

[tango1]

delta 5.8 90 mar 2 stroke standard prop light load.
problem is that it gets to it full speed 35 knt easy but with loads of extra revs to spare. my thoughts are that if i was to change the prop to a bigger size or pitch, it should go faster and in turn give more economy at 35knt or am i talking a lot of s--t if not what size and has anyone got one for sale?
cheers

[Turbodiesel]

When you say lots of revs to spare, do you mean its not revving high enough? Your engine should rev to about 5400rpm (i think from memory). So firstly you need to get the revs right. Putting a bigger prop on will make your top end quicker but also reduce your pick up, the engine will under rev and put extra strain on it as its working to hard and loose fuel economy. If its over revving you will loose top end but gain on pick up and again knacker your engine as its revving its tits off.

[tango1]

the engine over revs eg 5400 =35knts but it will go up to about 6000 with no further speed but i did let it it do 6000 for any of time! only a few secs. i understand it is the standard prop that came with the engine. i feel there is more power to be had out of this engine.

[Nos4r2]

There will be a number on the prop. It should look something like 48-1235779-17P. The 2 digits before the P are the prop pitch. What do they say?

[Turbodiesel]

Originally Posted by tango1

the engine over revs eg 5400 =35knts but it will go up to about 6000 with no further speed but i did let it it do 6000 for any of time! only a few secs. i understand it is the standard prop that came with the engine. i feel there is more power to be had out of this engine.

If it will rev to 6000rpm you will probably need to go up by 2 pitches.

[tango1]

i was at the boat today this is what i found. 4877342A4515p. i hope this helps
thanks

[Chris]

Looks like you are running a 15" pitch prop which is why you are overevving, you could easily run 17" and or possibly 19" on that combo.

[Nos4r2]

I think Chris is right. If you're using it for diving a lot and carrying a lot of people/gear then I'd start at a 17" pitch standard quicksilver ally prop.