Repowering a Mako

[Codfisher]

Hello all I am new to the forum and am interested in learning about repowering a Mako. My interest in this developed after seeing a friends (Mist Rest)83 that he repowered and provided us with a solid fishing platform for offshore ground fishing at much less cost than purchasing new.

My first question is how do you know if a certain motor will be compatable with a given hull. I am thinking primarily of using 4 strokes (in addition to ground fishing we do a lot of trolling for bass and tuna) .Given their added weight how does one determine if the hull can handle it.

As you can tell I Know little about this but am willing to learn.

[Prop Blast]

Hi Cod,

Matching an engine to a particular hull is not rocket science, but there is a bit of research that goes into doing it right. You cannot just issue blanket statement such as, "A boat "X" long with "X" beam needs "X" horsepower. Same thing goes for 2-stroke versus 4-stroke.

The Max HP rating that the manufacturer provides is a good start point. If a boat has a max hp rating of 250hp, something like a 225hp is probably going to run fine. A 250hp will give you more top end speed, and work less hard at a given RPM, but will cost you in fuel consumption.

Boats with deep V hulls require more HP than semi V's. A boat with 19 degrees of deadrise will get on plane quicker than a boat with 21 degrees of deadrise, give the same engine, prop, and conditions.

The presence of bottom paint, a T-Top, full crew, ... will all cause a boat to need more HP than a boat with no T-Top, 2 people and a 1/2 tank of gas.

Some people say that 4-stroke engines have a poor "hole shot", i.e. take too long to get up on plane. I disagree -- if you've got the engine matched to the right hull. I have a F225 on my Mako -- installed against the recommendations of a close friend who rigged the boat for me -- he felt I should go with the 250hp HPDI from Yamaha. His rationale was that he had recently installed an F225 on a Mako 211 and the boat ran like CRAP! That's basically the same boat as mine; just 18" shorter.

Well, I saw that boat -- the guy had a T-Top and crow's nest on it. The T-Top was WAY TOO LARGE -- would have been perfect for a 34' Venture! No wonder the boat ran like crap.

The day we took our water test was a tense day for both of us. I'll cut to the chase - the boat and engine are a near perfect match. My friend was impressed. I have both bottom paint and a T-top (but a reasonable one). With 3 adults (full load) I'm on plane in about 4 seconds, with a top speed of 43 MPH at 5,800 RPM. At cruise (4,000 RPMs) I run at 31 MPH and burn just under 10 GPH. But this is my boat.

Jump to a 23' Regulator and a single F225 probable won't work well. Why? The Regulator is a little bit wider and has 23 degrees of deadrise versus my 19 degrees.

Weight. If your transom is in good shape, a single 4-stroke probably won't affect anything. My boat's float line didn't change a bit -- but I did move my two group 27 batteries from the transom area to the console. One more point. Todays DFI and 4-stroke engines require better batteries -- don't scrimp here. I did a little overkill and put in 2 AGMs (at $140 ea) and haven't regretted it.

Hope this gives you some insight...

Tom

[Alcedo]

Just to give ya an idea of differences. You see what the f 225 will do. I too have a Mako 21. I have a 92 225 Johnson, carbed 2 stroke, slings a 14 1/4 x 21 SST prop. These numbers are with 50 gal of fuel and one 230 lb guy per GPS and Navman fuel computer.

WOT, 6000 RPM, 51 MPH.

Cruise, 4400 RPM, 32 MPH, 14 GPH. 2.28 MPG....not bad.

A two stock stroke will usually out perform a stock 4 stroke on any given day on any given boat and with the new technology ie ETEC, you will see as good if not better gas milage with the 2 stroker.

Just food for thought.

[Trident]

Codfisher-

What year is your Mako? On a small hull like the 17 you need to be especially careful about how much weight you put on the stern. If you do go with a 4 stroke you will probably need to go with a lower hp because of the addditional weight.

If I was you, i would repower your 17 with a 2 stroke in the 115hp-130hp range. The power to weight ratio would be ideal for your hull.

I work for Baert Marine and would be happy to give you a quote for a repower.You can give me a call at 978-462-2846

Ed

[Codfisher]

Thanks for the replies guys...really appreciated.

Ed- I have been to your shop on occaision and know of the quality service your company provides. I have just started my search for a good "classic" Mako hull in the 22-25 ft range. My initial question was to reassured that a 4 stroke could be put on a hull in this range...seems like Prop Blast was able to do it.

I am not into hole shots and 50+ knts WOTs...there arent many times in our area (as you know) that you can open it up without requiring back surgery the next day. I am into the quiet , reliability, ease of service, no oil mixing and fuel economy a 4 stroke will provide.

I will definately give you a call if I find what I am looking for.

[jbsmako]

I just repowered my 1973 23' Mako with a 200 Honda 4stroke and it has never run better and the hole shot is great turning a 15X19 prop. I did have a 1987 200 Evinrude on it.

Jim

Jbsmako

1973 23'Mako