What propeller have I got? (2000 Mariner 40HP)

[alt]

Hi all,
I have a 2000 Mariner 40HP 2 stroke on an Avon SR4.

The proper got a little dinged and I want to replace it. Infact, the damage is so little, many would continue to use it, however I feel that I could go up 1" pitch as the engine appears to be screaming at WOT.

I don't have a tacho.

I am currently achieving 52Kmph (against a 3Kmph current) and she gets on the plane easily with 2 onboard and loaded with gear.

I would be happy to stay with the current dimensions prop, but I haven't a clue what I have.

The ONLY marking is on the hub and it states 20 A. I took the prop off, nothing at the front of the proper either, as said 20 A is the only marking.

I tried a friends SOLAS prop, 11.1x13 and I achieve 47Kmph. I'm guessing I have a 14" prop?

Don't suppose anyone has a similar set-up and can advise what prop they have? The boat is used for cruising mid-range. I would be more interested in efficiency and top-end rather than hole-shot.

Many thanks.

[paintman]

Originally Posted by alt

The proper got a little dinged and I want to replace it. In fact, the damage is so little, many would continue to use it, however I feel that I could go up 1" pitch as the engine appears to be screaming at WOT.

I don't have a tacho.

Can't help with suggested size but you really need to check revs at Wide Open Throttle with the boat carrying its most normal load & correctly trimmed before changing props.
You might find that the current prop is actually 'the one' or that you could go up more.

Plenty of really cheap inductive tachos on ebay (search for 'tachometer' not 'inductive tacho') - IIRC there have been a few recommended on this site & hopefully someone will link a thread.

[Limecc]

As Paintman says, you need the rpm. Then we can estimate the slip and calculate the probable pitch. However:

47kph with a 13" prop @ 5270rpm
49kph with a 13" prop @ 5500rpm

52kph with a 14" prop @ 5500rpm
55kph with a 14" prop @ 5726rpm (unlikely)

51kph with a 15" prop @ 5000rpm (27.7 knots)
56kph with a 15" prop @ 5500rpm (30.5 knots)

Your WOT range is 4500-5500rpm
Assumed 10% slip, gear ratio is 2:1

[alt]

Thanks for the help.

I compared current prop with the 13" pitch, and the 13" looks like a lower pitch than my current prop. I went to another Mariner 40 in the yard and it has a SOLAS 14" pitch, looks identical.

I suspect I have a 14". I really think I could go up to 15" and i'm willing to take the risk.

I suspect my current prop is a genuine Mariner / Mercury. There is just the thrust washer, the prop and then after that the locking tab and nut.

I notice the SOLAS props I am Googling, it's as if it requires a (almost like a thrust washer) piece with the locking tabs... i'm afraid if I order a SOLAS prop, i'll need to source this part and I don't even know what it is.

To give an example, this is what my prop looks like, with the locking tabs built in to the hub:
https://muzikercdn.com/uploads/produ...n_1aaef141.jpg

I'm guessing the SOLAS props will come as such:
https://cdn11.bigcommerce.com/s-uprk...716392.jpg?c=2

Does anyone know of a reliable online supplier, whom I could ask before ordering to be sure it will bolt straight on? I'm in the West of Ireland so need to order online, no one local.

[alt]

PS. Engine is a 2001 40HP 40LPTO

[Limecc]

Originally Posted by alt

Thanks for the help.
Does anyone know of a reliable online supplier, whom I could ask before ordering to be sure it will bolt straight on? I'm in the West of Ireland so need to order online, no one local.

I should have mentioned I think you have a 14p.

Call Steel Developments who are reasonably priced and offer one free adjustment up or down if the 15 doesn't work out for you. Purchase is risk free. They will advise and sell you what you need.

[alt]

Many thanks for your help!