Repower suggestions for pontoon houseboat?

[BoostedTimmy]

I've been remodeling a 1987 Landau pontoon houseboat for a little over a year now. Just recently I got the Force 85 it came with running and got to do some cruising. While I've been through seemingly every inch of this motor I still don't quite trust it (it sat unused for 1 possibly almost 2 decades) so use has been limited to about 1/3 throttle. This moves the boat at a modest 5mph or so. That's a pretty comfortable speed but I suspect once I trust the motor more I'll find 7-9mph to be the real sweet spot for cruising.

When I bought this project I knew even if I got this motor running I would probably want to repower. Ironically now that it is running I want it gone more than ever. The smell, the noise, the vibrations, premix, and the lack of tilt and trim are a real buzzkill to what is otherwise a sublime experience. My wife and I are both in agreement that this is a boat we want to keep as long as we can and a repower is in order. I've started researching and talking to various people but opinions have varied widely so am curious to hear from those who may have similar boats.

My questions/concerns -
85hp. The first question I always get is "Is that enough?" with the immediate suggestion that I consider the ~115hp models. Personally I think it's plenty, in fact, I see the Catamaran Cruisers Lil Hobo with 60hp and am leaning going that direction since I have 0 desire to make this boat plane. Is there anything wrong with this? I think my main concerns would be overworking the motor or not being able to make headway into strong winds (not that I *plan* to ever be out in the wind).

2s vs 4s. I was thinking 4s would be better for cruising and economy but since this boat lives in the water I'm slightly worried about maintenance. Everything I do has to be done over the water and I much prefer to do all my own work so the idea of a modern 2s is very appealing. Also, which do you think would be happier at my target cruise speed? Top end is of very little concern to me.

Brand. I know there is no right answer to this, but would any brand in particular stand out for my application? I thought I saw something about a feature Hondas had for pontoons that increased maneuverability. Gimmick or valuable? I was also told Evinrude has a 7 year warranty right now, which sounds nice.

Any advice or ideas on this would be appreciated! Attached a pic of the boat, unfortunately the only pic I have that shows the whole thing.

 

[HotTommy]

1. I suggest a new 4-cycle outboard in the 85-90 HP range.
2. I put a new Mercury 4-cycle on my old pontoon boat two years ago and I love it.
3. Going from 85 to 115 HP will increase your top speed by roughly 15%, or maybe 1 MPH. I don't think its worth the higher initial cost, added weight or higher fuel consumption.
4. My boat is very different from yours, but I find the sweet spot for cruising is 3,000 - 3,500 RPM.
5. My only maintenance so far has been annually changing the engine oil and lower unit oil. I'll change the impeller the first time this winter.

 

[Scott Danforth]

your limited to displacement speed on a pontoon houseboat. it will move nearly the same speed with a 50hp as it will your 85hp which will move about the same as 150hp. not until you can get the boat to plane will it go much faster.

 

[ahicks]

Merc has the "Bigfoot" series of engines that might be worth looking into for 'toon power. Available in 2 and 4 stroke, it amounts to a gear ratio that lets you run a little larger dia. prop. Worth it? Geez, on a boat the size and weight of yours, it may be.

I'm a never go back now, spoiled rotten, 4 stroke convert and make no apologies for it. I work on a lot of 40-90hp Hondas for busy work (retired), so they're my favored brand. You'll need a tach for sure on a boat that size, as unless it's dead quiet you are not likely going to be able to hear a 4s engine running.

Once you have a 4s fully serviced (t-stat, lower unit seals, carbs gone through meticulously, fuel lines, etc), they're not going to need a lot of attention. Same with a 2 stroke. The only difference is you need to change the oil annually on the 4 stroke. Seems like if I were forced to do all my own work while in the water, it wouldn't be that hard to find a nice sand bar sporting knee deep water?

Big enough? Have you ever driven one of those 75' houseboats they rent out by the week? Those work incredibly well in the hands of a driver used to working with them. Been a LONG time, but I don't think they have much for an engine. I think maybe 75-90 hp would be plenty for most conditions. Currents and wind would be what I would judge it on. If there's frequently a lot of either you may be wishing for more power.