props

[olly]

what props fit a 4cyilender 2 stroke 40hp mariner ?
whats the best pitch and so on? any help would be good
thanx
olly

[Sunny]

I'm sure you will get a lot of replies Olly.... tons of guys who know this subject.

Ask Scotty or John (Monkeynuts) ... amongst two of the specialists in that area

[olly]

thanks sunny
ill give it a day b4 i pm any 1

olly

[sailorboyrob]

As Sunny said mate, you need a specialist to answer that question, what works well on one set up wont work at all on another, even though on paper they may seem very similar.

[BrianR]

"whats the best pitch and so on?"

Depends on type of hull, weight etc.
You could try Castlemarine's propcalculator

[olly]

hi
iv taken my prop off as 1 of the blades has a bit missing.its a 13p is this the pitch?i have a stainless prop that fits but its a 12p.its going on a wilson flyer type hull

olly

[monkeynuts]

yes the 13 p is the pitch so the other prop you have is a smaller pitch
as said above olly, hull type,wieght,lenth and gear ratio are all needed as well as power.
the easyest way is to find another boat and engine and see what prop it has and check its revs are correct.
if you have the other prop you could just try it .just make sure you are pulling the correct revs for your engine, on my old merc,it was stamped on the top of the flywheel. other wise it will be in the owners or workshop manual.
the revs are most important, to low and you will be overloading the engineand be kiling it plus drinking fuel like no tomorrow. to high and the engine wont last eather.
cheers john

[backdraft]

olly do you have a rev counter fitted. as its very hard to get it set up right with out one. ive been here a few times. and getting it right makes one hell of a differance.

[olly]

no i havent but im sure i can get 1 to set it up

olly

[Equity]

Sounds like you'r gonna have to buy a new prop.The question is Aluminium or stainless steel ? 110 or 220 quid ? Swapped my 15 for a 17 pitch with the holes drilled for acceleration (that's the theory) on my raider .Huge difference on fuel consumption.Always thought it's a shame you cant try before you buy.

[I DUNNO]

there is more to it than you think, depends on the size of engine the gear box ratio, and the type,weight and displacement of your boat. when you phone up to order one they ask you these questions and work it out for you on their computer

[olly]

i do have the prop that came with the boat but it has a chunk missing.iv also been given 3 brand new props.1 is the same witch iv put on.the other fits but the blades hit the anoid? i think thats what its called.the blads are a tad bigger but not as wide.the 3rd is a stainless steel prop but its way too big for my engine.i think its off a big mariner

[Equity]

Personally ,I wouldn't even try a second hand prop.It only needs to be slightly bent /damaged and the stress put on the gearbox could be potentially fatal.

[Canuck]

If you think the prop with the chunk missing is the right one, you could have it repaired for £35-40 Steel Developements used to be good they did about 6 props a week for us and we had no probs( I'm not suggesting their not now, just haven't needed to use them for a long time). theres also Streamlined marine Aldershot way - I haven't used them.

Rich

[moonstone]

there is place on bembridge that does prop repairs habour enginering buy bembridge outboards