Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outboard?

[micromachine]

I just picked up a mid 90's 20ft Gambler bass boat with a 200 Merc Lxri EFI 200hp outboard that has no compression in cylinder 6. Someone estimated the repair cost to be over $3k which is more then I have to spend right now so was going to just replace it with a cheaper used outboard from craigslist as someone offered me $950 for my dead motor and I figured I could use that money towards a cheaper alternative if I just sell it (or they said they would put a 200-4 carb'd power head on it if I gave them my power head+$1500). Fishing is just a hobby for me anyway and I'm not a mechanic.

I realize bass boats are meant to go fast for tournaments, but as a non-tournament fisher I don't need to go 75mph to enjoy a day fishing on the lake. Is there any other reason why bass boats have such large motors and can I safely replace it with a smaller one (and if so, how small) without getting to the point where my rpms are maxed all the time when I want to go from point a to point b? My primary goal is to save fuel, and don't need the 200hp size if it is costing me more $$ in fuel consumption. I realize though that at some point, going with too small a motor would hurt my fuel consumption because the rpms would be much higher then say, a larger motor at the same given speed.

I saw a nice Merc 90hp four stroke for example that I thought would be nice, but am not sure if it would be big enough for me to get it on plane. I rarely go over 40mph on the small lakes I fish. Would that motor be undersized? Is there a formula or chart or anything I should use in determining what motor sizes I should consider?

Thanks for your help.

 

[metriccrescentwrench]

Re: Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outbo

What's the boat data plate say for max. HP? There's a rule of thumb floating around that you should have at least 70 percent of max hp - but that's really just a scientific wild a#$ guess.

Just off the top of my head I'd think a 90 on a 20 ft bass boat would be kind of small. Maybe you could find a 140 or 150 in good condition, you'd probably be happier.

 

[rodbolt]

Re: Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outbo

I actually have a very clean low hour 200 EFI merc of a 1995 vintage that I may part with.
PM me if your interested.

 

[5150abf]

Re: Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outbo

The rule of thumb is 70% of max HP but I don't know that that applies to a bass boat that is rated for 250-300 horse.

A 90 should do really well on that and plane the boat nicely, you need to remember you will be losing several hundred pounds of engine.

 

[ezmobee]

Re: Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outbo

I weep at the thought of an underpowered Gambler

 

[Frank Acampora]

Re: Replacing Gambler bass boat motor-can I replace a 200hp Merc with a smaller outbo

A four stroke 90 on a 17 or 18 footer might be ok, but I think you will be unhappy with it on the 20--even if it is a bass boat. ---Even if you don't want to race to the fishing hole. It is nice to have a LITTLE more power than you intend to use, sometimes it comes in handy.

Four strokes just don't have the low end torque of a two cycle and hole shot is certainly going to suffer as might fuel economy, and of course, top speed; you just might need to keep it close to wide open to stay on plane adequately. I think as said above, a decent 140-150 is more in line with that hull.