Yamaha 55 prop info/help please?

shoestring · 23 June 2013, 21:31

Hi I've got a 1993 Yamaha 55 on my old SR4 the props a 13 pitch and i'm looking to go up a couple of pitch sizes would I be right in thinking its a 'G' series prop that's fitted? Thanks in advance AL

9D280 · 24 June 2013, 17:06

I had a G on my old 55, so I guess so.

That on an SR4? I reckon you could go up more than a couple - I had a 14" on the Yam pushing my current 5m lump along.....

If you do replace it I could be interested in the 13".

shoestring · 24 June 2013, 17:20

Thanks (once again) for the info I'll see how I get on and if I do change it i'll be in touch re the old prop. Biggest problem seems to be finding one used there seems to be plenty available for the larger engine but seems a bit thin on the ground for the smaller unit. Might have a trawl through the list your prop thread on here if its still going, regards AL

Locozodiac · 24 June 2013, 19:32

Shoestring,

Why do you want to re pitch blindly ? Do you have a tach installed to know your exact wot rpm and if inside safe working min-max revs factory stated for that engine ? If over reving would need to go some + pitch to lower rpm down, but that you don't know, right ?

Happy Boating

shoestring · 24 June 2013, 20:24

Hi I take your point I don't have a rev'ometer/tach on the boat and what you suggest is the safest and correct way to do it. Its based on the fact that it very easily gets on the plane and at W.O.T seems very high rev'ing although the chine walking soon takes your mind off this

We don't carry any weight rarely more than 2 people. Although only a small boat it had dive bottle racks fitted when I bought it so it was almost certainly Propped to carry more weight. I've had different people on the boat say that it could do with going up a prop size or two if not more as said earlier. Occasionally Tow quite a big Ringo and obviously the engine labours more to get the boat on the plane so I was just going to try 2 sizes up as a start point should one turn up etc..

Locozodiac · 24 June 2013, 20:59

Induction tachs are quite cheap way to go, check Hardline or Tiny Tach models, get the one that has programmable firing sequence. You could have 2 props, the one currently used to theoretically carry more weight and a spare for fine tuning engine rpm to match any other boating application, skiing, wakeboarding, pulling tubes, bananas, whatever.

That way will know exact working rpm parameters at wot with current prop in use, and go from there sellecting a proper +,- pitch for any other application.

Happy Boating

9D280 · 25 June 2013, 22:44

Quote:

Originally Posted by shoestring

Biggest problem seems to be finding one used there seems to be plenty available for the larger engine but seems a bit thin on the ground for the smaller unit

Tell me about it......

If it's any help I have a Yam 2 wire tacho doing nothing..... £40 it's yours.