Advice on outboards

Recently bought a new boat, a second hand Surtees 4.85 centre console. Sweet little set up. It came with a 2011 Evinrude 60hp 2 stroke (only done 210 hrs) which pushes it along fine with just me in he boat, but took out my son and his mate the other day and coming back into steep wee chop struggled a bit to get up on the plane and had to get weight forward to get planing. Will leave as is for now but wondering about getting something with more grunt on the back . Would one of the new 4 stroke 60 hp motors ( Yamaha, Merc, Suzuki, Honda ) be more powerful than 10 yr old 2 stroke ? Or should I look at 70 Hp motor ? I see Yammie do a 70hp that is pretty much same weight as the 60’s ? Or other suggestions ?

Sounds like you may have had your outboard trimmed out too far. I have a 70 hp 2 stroke on my stabi 509 and it goes well, cruising at 27 mph with top speed of 32. I suggest looking at how you have distributed weight in the boat, as it certainly bogged down. Use the trim gauge indicator to ‘feel’ where boat goes best. You may even see the revs change by simply changing from bow up to bow down trim.

pitch of prop can make a huge difference to holeshot (at expense of top speed) does that model of surtees have the stability at rest ballast tank that empties as you get underway? that might be affecting holeshot so a lower pitched prop might help, be worth talking to surtees about it.

Valid observation. I forgot that Surtees had that flood chamber, so when it rests, it fills with water for stability. When taking off, the water is meant to pour out the transom flap. With water locked in, the trim of boat would be severely affected, hence passengers having to move forward. Try locking flap before using boat and see if the lack of water in bilge affects trim. Bet it does.

Have played this exact game on a 4.7 Surtees Centre console. Older model, but same dimensions and weight pretty much as the 4.85.
Mine has a yammy 60 4 stroke. A permatrim fixed it right up.

My observations and findings:
The permatrim allowed for quicker holeshot, slower plaining, and less cavitation.
A bit of work was required to get the correct pitch prop to tune the boats performance to meet my needs.
A 4 stroke engine is heavier for the given HP than the 2 stroke equivalent. This is a real problem for the small surtees CC's, as there is no cabin giving any weight up the front.
Moving the battery(s) into the Centre Console helps solve a bit of the weight aft problem.

If I were to start over and get a new build, I'd probably be looking at a modern 70hp 2 stroke. The engine costs less, weighs less, produces the same HP as a 70 4 stroke, costs less to service, and uses almost the same amount of fuel as the modern 4 stroke engines. Having to add 2 stroke oil is only a very minor inconvenience.

thanks all for the comments and suggestions. Batteries are located in centre consol, fuel tank is underfloor just in front of the consol. So that sounds like the theyre in the right place for weight/balance. Yes the Surtees have underfoor central flood chamber, and its set up to be open so empty while plane but floods while stationary. I did fiddle around with trim settings - seemed to have incredibly small margin of error to get the trim level. Very slightest touch in or out on trim and the indicator would go high or low real quick. I've come from larger boats with separate trim tabs, and found them bloody marvelous. Excuse my ignorance but what's "permatrim". The outboard is fitted with large rubber? or plastic? planing trim tabs things ?

Yep, that big winged ‘stingray’ looking thing bolted onto the original trim plate of the outboard.

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Originally Posted by chainsaw

thanks all for the comments and suggestions. Batteries are located in centre consol, fuel tank is underfloor just in front of the consol. So that sounds like the theyre in the right place for weight/balance. Yes the Surtees have underfoor central flood chamber, and its set up to be open so empty while plane but floods while stationary. I did fiddle around with trim settings - seemed to have incredibly small margin of error to get the trim level. Very slightest touch in or out on trim and the indicator would go high or low real quick. I've come from larger boats with separate trim tabs, and found them bloody marvelous. Excuse my ignorance but what's "permatrim". The outboard is fitted with large rubber? or plastic? planing trim tabs things ?

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Permatrim is a make of a extended cavitation plate. All alloy, so good and robust, and generally speaking have a larger surface area in play than the dolphin tail type. When the engine is set to the correct height on the transom, there should only be a few mm of water running across the top of the permatrim when on the plane. If the engine is sitting too low, you will have a lot of drag, and poor performance.

Smaller engines quite often have a single hydraulic cylinder, for both trim and tilt. As a result this is faster than larger engines that have separate dedicated trim cylinders.

I assume you are trimmed right in when trying to get on the plane?

Fairly well covered above but I will add.
60 two stroke should be enough on that boat if properly loaded and trimmed.
60 hp two stroke and 60hp fourstroke are two completely different things....if it struggels with the two it likely wont even get on the plane with a 4.
Rated hp is developed at max operating rpm what is needed to get out of the hole is torque and 2 stroke is king there.

Trim is not a set and forget thing on a small boat.....its constant adjustment.

To get on plane motor should be trimmed in 80-100 percent of the way in. Accelerate and as boat starts to lift out of the water trim up slowly (just tapps on the up button) untill on the plane.

At a good cruise speed (hull fully on plane not dragging its arse) on flat arse water trim up in small taps on button every 5 seconds or so until the motor cavitates (revs up for no reason) orthe boat porpoises (bounces around for no reason) then trim down in small taps until the cavitation or porpoiseing.

This condition on flat water is your maximum trim and generally most economical cruising.
Any other sea state will require you to trim down from this point to either prevent cavitation or porposing.

No trim gauge on my boat but you soon get a feel for it.....from flat water best trim at cruise ,before taking of again I give it a second or so on the down button before taking off then trim up till hull is happy.

And yes permatrims are a big help with trim control on small boats and also planeing at slower speeds.

People are your easiest moveable ballast
..us them to get your nose down then move them back once on the plane..same with dive gear ..easy to stack at the start of the day
..but remember to put weight belts and tanks back into position on the cruise / punch home ..boating on a calm day and driving a boat in rough conditions ard two very different things ..move your load accordingly

Had a McLay 590 Hardtop with a Merc Verado. A permatrim was probably the best and cheapest accessory I added!