As I recall, I had a 15 inch SS prop on my 90 etec and got about 5100 rpm. Definately want more than 4600 rpm, low revs no good for the motor.

Preference would be 5200-5500 I think.

With the info you have you should be able to take it to a dealer and they will tell you what prop you need to get the best revs ect

 Dont worry about the  foil . The correct prop will fix your problem. 

Your prop should have markings on it. Mite have to take it off to see them. Will certainly help give us a idea where to start.

I bet you would have a 17" sst on it. A 15" raker would work well l recon. Do a google search on brp props.

From memory the 90hp optimum  rpm is 5200.

 Definately hunt online to check best prop. There are a few sites that after you enter the motor, boat length and hull material will give you the reccomened prop.

I dont know your boat size and weight but I have an 18ft glass with a 90hp, I have a SS, 13 1/4 inch diameter with 16 inch pitch and get WOT 5800rpm, 30knts.

Good luck and report back how you go.

Contact galeforce and ask them ? Forget the foil , get a 4 blade will help stern lift

 Tow the whole rig to 'just props' in ossy park... Save yourself the guess work and if you end up with the wrong prop they'll change it

Thats what i'd do.. 

 i have a SST 15 inch prop you can try if you like 

 It was of   a etec 115hp ,

pm if interested

ROB

17" prop on my Seafarer Vsea, 90 etec, will do 5000rpm, and cruises sweet on 3500. Economy is also superb. Probably not as fast out of the hole but is a great cruising prop.

 Thanks guys. Being in Exmouth makes it a bit hard. I went through the same issues on my last boat with Solas in Brisband and cost about $200 posting props back and forth. I am heading down to perth next month so might bring the prop down then and see what they can do.

Fish200red thanks mate pm sent.

noting you have no trim range (why) the other question would be is the motor mounted correctly height wise??  Hard to tell from the pics with the motor raised but it looks like if tilted down the cavitation plate would be well above the bottom of the hull.

Might want to check that first before changing props...

 Hey bouttime  brp props have name on side if it ie `raker or `rebel .I reckon a 15" rebel would suit you. They are fairly cheap to buy from dealers and you can swap them if not happy.I run a 17 " most time and a 19" on long trips less speed more ecomony.

My advice would be to forget you even heard of a hydrofoil and go for the smaller pitch prop.
Been on and seen too many boats performance stuffed up by sticking a foil on.
They will give you lift sure , but in a following sea that is definitely the last thing you want. On minute you are cruising sweetly then along comes a swell and all of a sudden you are surfing down the face with next to no steering and around and over you go

The motor is on the bottom mount so can not lower it any more. I can trim it out but it will just hull slap and it gets very flighty at anything over quarter trim. Not sure a change in prop will fix this.

When I get a chance I will take the prop off and have a look to see if there is any other markings on it. All I can see is the SST stamped on the side.

The foil I am fitting is one of the Ozhydrofoil alloy plates which is an extension of the cavitation plate. Same as the Permatrim foils. A mate put one on his seafarer and it improved the boat heaps. He had the same problem as I have now. I have fitted one to another boat in the past it it worked well even in a following sea. The boat is only really for fishing in the gulf and the odd trip on the west side so wont be travelling in big heavy seas. I will make a few calls on Monday and see what Galeforce have to say before I fit one.

Thanks for the imput.

would like to see a pic from behind at cavitation plate height with the motor down.  As above may just be the angle of the pic but have seen a similar problem before

 I will try and get a better photo tomorrow.

Ok so i found the prop size, its 13 7/8x15. Prop number  176571 S.

It looks like its an alloy prop as the magnet sticks.

I will give the dealers a call tomorrow and see what they say. Will try and find a stainless prop to fit.

Have added photos of the motor height.

Cheers

 Mate l would be raising that motor. Its way to low. Put it as high as it goes. You will certainly  gain rpms and mite solve your porposing problems. If you get any cavitation drop it down one hole.

Get engine height right  before out laying money for a prop.

 If i raise the engine how do i then stop the hull slap/porposing. As it is now anything over 1/4 trim and its very flighty and will hull slap even in the smallest of chop. 

Cheers

 Its all one step at a time. You wont know till you try these things and it wont cost you anything. Raising engine can be done easliy in drive way using the trailer jockey wheel.

You want to see the top of cav plate once your on the plain.

Once engine height is right then look at props if raising engine doesnt help with the porposing. You will certainly gain  rpms  lifting the engine though.

cavitation plate should generally be level with the bottom of the hull (hence just visible sitting on top the water when planning), the original pics with motor raised gave me the impression it may have been way higher (that and the no trim range bit made me question the height), new pics seems to show (better but still not an ideal angle to say for sure) this is about right.

Whole heap of factors could be at play with the trim/slap (angle of transom, weight distribution - fuel, eskys, persons etc).

Has the prop been changed at any point by anyone else - is it the standard/recommended prop for the motor??

Agree foil would be a last resort

I have tried the esky up the front full of ice and also when travelling 2 up have the other person up the fron also. It does make a difference in ride but can be uncomfortable for the person sitting up the front.

I am not sure if it is the original prop. Trying to get hold of someone in the know to find out.

I am heading out Saturday and will have a look at where the cav plate is sitting whilst cruising.

Cheers

 Paul H. The prop hes running is the bog standard cheap prop most Etec dealers use on the lower hp motors. They aint going to mount a $600 stainless prop on at there cost. Most etec buyer think ,hope that the dealer has set it up correct and off they go boating. Not alot of owners know any different, Who ever set the boat up originally when motor was mounted didnt go off Brps rigging guide lines to prop the motor to optimum rpm and get engine height  right , l wonder if they water tested the boat when motor was mounted.

I owned an Etec from new years ago and had all the same issues , not reaching correct rpms , motor to low. It cost alot of time and money in the end and l still didnt get it perfect . Best thing l did though was to join the etecownersgroup.com and found all the info l needed. 

Bouttime l recon you take alook at there site and ask some questions over there. 

I have just talked to the chivers guys about this, i have got my hands on a 15" prop which im going to try on mine next week. i will let you know how it compares to the 17" ive had on it. Im up in Exxy in April and will be bringing my rig, if you havent got it sussed by then you can borrow a few of my props and try them if you like? 

 the motor looks like its right hieght

I have a stainless sst 15inch prop if anybody needs one $250

pm if interested

cheers rob

Thanks guys, spoke with Luke from Chivers and he is very switched on. He recomended a different prop which i will try and source second hand if i can. Will still check the cav height on sat when i get the boat out.

Fish200red do you know what size prop it is and the code. Might be interested.

Albee might take you up on that if i have no luck.

Cheers

 Can l ask what prop he recommended. 

 numbers are 13 7/8 x 15 , 176571

 Ring Max OGrady. He is a guru

Join etec owners group and speak to Huey from Huey's Marine in Sydney, he is a moderator on the site.

Provide engine details, and he will give you good advice.