Setting up an sr5.4

Nos4r2 · 12 July 2007, 19:58

Any suggestions on setting up a 5.4 Searider?

Quote:

Originally Posted by walruz

Depends on how many tree huggers live near you. I can only achieve a pitiful (??) 36.5 knts with my 90

That's about what my 5.4 makes with the 85. I think there's some improvement to be had though. I'm hitting max rpm at that speed so I think another 2" on the prop pitch should help.

What diameter/pitch are you running and what holes is your engine on?
Mines 13x17" and I can drop a hole if I want.
I probably will drop a hole as I find I cavitate a bit when cresting a wave even with the stern firmly in the water.

Searider · 12 July 2007, 22:39

Made 39.7 with my 5.4 with 90hp Mariner 2 stroke. 2 up 90 litres of fuel.
5400rpm
Cavitation plate level with bottom of boat (maybe a little lower than that possibly). Would have raised it up a bit but sold the boat before having the opportunity to try.
20" Lazer II prop which had been balaced by Propeller Revolutions in Poole
Engine offset 1.5" to starboard

My boat was probably quite light - it was a 1978 leisure spec - I believe that the commercial / military spec boats are heavier - not sure which spec you have.

Nos4r2 · 12 July 2007, 22:52

Mine's the military spec boat. I wonder if there's a difference between the Yam and the Merc box ratios?

ian mcconnell · 13 July 2007, 11:01

hi Nos

I had the standard 13 x 17" yam prop on mine, and with the extra consoles and seats and 80ltrs i made 36knots.

I then went to a Titan stainless prop also 13 x 17" i now make 39-40knots with the same setup. The stainless titan gives the prop more grip in the surf & and has a larger surface area, and yes definately lower your outboard to its lowest setting, i still occasionally have problems when i have too much weight up front.

hope to see you out on the water one day

ian mcconnell · 13 July 2007, 11:03

i forgot to say thats between 5000-5100 revs on a 90hp yam, which is right within its power band

Nos4r2 · 13 July 2007, 19:56

Cool, thanks Ian.

It'd be interesting to get a load of 5.4s in one place and see what they can do...

mcinfantry · 13 July 2007, 20:00

can anyone show a picture of the motor down so i know where to mount mine?as in what height???
i have a 75 etec. ad a 5.4 (i should get my boat sunday or monday.

Nos4r2 · 13 July 2007, 20:22

From what I've seen on mine I'd put it so that the antiventilation plate is just below the V. Mine's just above and I need to drop it down.

walruz · 14 July 2007, 13:29

Quote:

Originally Posted by Nos4r2

Any suggestions on setting up a 5.4 Searider?

That's about what my 5.4 makes with the 85. I think there's some improvement to be had though. I'm hitting max rpm at that speed so I think another 2" on the prop pitch should help.

What diameter/pitch are you running and what holes is your engine on?
Mines 13x17" and I can drop a hole if I want.
I probably will drop a hole as I find I cavitate a bit when cresting a wave even with the stern firmly in the water.

Sorry for not getting back but the internet was down all day yesterday in the Scillies. (BT hold your hands up).

Mine is a rebuilt 91 2 stroke Yam and I had to run it in like a new engine.

Don't have a rev counter but I started with a 17 inch 3 blade ally prop (won't use stainless down here - too many rocks to hit and with SS that means a F$%^^D gearbox - someone I know did just that last week and they have been boating here for over 20 years

). Found that had too much torque on low speed handling (only took seconds to plane tho

- keeping that for skiing and tubing). Spoke to the Yam dealer over here and he recommended the 19 inch and it is a dream - it has done everything I've asked of it. Mind you because of the aforementioned rocks my normal travelling speed is circa 22 - 24 knts. Also fuel is VERY expensive down here

so I try to run a little more efficiently until I feel a need - the need for speed

.

Also my wife is 5 months preggers and so has now stopped coming on the boat so I can open up more now with just the guys on board.

Any enough rambling. Engine is set up sitting right on the transom as that is how the old engine came fitted and it seems to run sweet. Lots of power but you also feel in control hence why I am a dedicated SR fan and around here it is normal to get some big seas. We are in the Atlantic after all.

Hope my ramblings have helped. Now I need to go play as the tide is coming in.

Last thought my boat is moored Feb to Oct so I spray every couple of months with acid to slow the weed build up which with my old engine cost me at least 2 knts.

If you ever come down this way please let me know so I can arrange a couple of days off to have fun showing you where all the seals etc are and maybe a run to Bishop's Rock lighthouse.

Ian

walruz · 14 July 2007, 13:31

Quote:

Originally Posted by mcinfantry

can anyone show a picture of the motor down so i know where to mount mine?as in what height???
i have a 75 etec. ad a 5.4 (i should get my boat sunday or monday.

Next low tide I'll try and remember to get one for you. But basically mine sits right on the transom.

Ian