Best engine for boat?

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jasonphoto01

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Sep 14, 2011
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I have a big heavy 20' aluminum boat. It currently has a 90 2 stroke and does 34 unloaded with just 1 person. I want to go bigger and need advice on size engine and whether I should go 2 or 4 stroke. Most of the time it will be used for a pack mule and going up and down river in both fresh and brackish water. I will also use to to tow another boat or move a houseboat on occasion. Alot of the areas have shallows so something that gets on plane quicker would be best thats why im leaning towards a 2 stroke.
 
J

jasonphoto01

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Re: Best engine for boat?

What kind of mph gains (with large loads in mind) can i expect in different sizes?
 
Silvertip

Silvertip

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Re: Best engine for boat?

There is a point of diminishing returns -- meaning simply adding HP only works to a certain point where the limits of the boat and its load are reached and adding more HP is a waste of money because there is no more performance increase. You should look at the capacity plate for your boat and not exceed the maximum HP rating. Anything up to that point is ok. But doubling HP does not double the speed. At your current HP you might see 5 MPH more speed and better hole shot with every 20 HP increase. That number would diminish as you go up in HP. But with no other information it is impossible to predict what you will actually see.
 
K

kahuna123

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Re: Best engine for boat?

The tow boat guys down here that are on the water 12 months a year run Suzuki's. The Marine Patrol runs them and Yamaha. The big Verados are having lots of issues.

4 stroke no low end. Better fuel longer lasting
2 stoke much better low end. And the ones that run everyday seem to last much longer than the 10 weekends a year motors.
 
lncoop

lncoop

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Re: Best engine for boat?

You also might want to consider a four blade prop if you're not already swinging one.
 
J

jasonphoto01

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Re: Best engine for boat?

Silvertip said:
There is a point of diminishing returns -- meaning simply adding HP only works to a certain point where the limits of the boat and its load are reached and adding more HP is a waste of money because there is no more performance increase. You should look at the capacity plate for your boat and not exceed the maximum HP rating. Anything up to that point is ok. But doubling HP does not double the speed. At your current HP you might see 5 MPH more speed and better hole shot with every 20 HP increase. That number would diminish as you go up in HP. But with no other information it is impossible to predict what you will actually see.
Click to expand...

Its commercially rated so there isnt a max hp plate. Its custom built with a fully enclosed cabin and very heavy.
 
J

jasonphoto01

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Re: Best engine for boat?

...if what you said is correct then a 150-200 would probably be ideal. Would a 150 give me that much better fuel consumption? It will get alot of use during hunting season then probably sit with very little use for 6 months out of the year.
 
K

kahuna123

Senior Chief Petty Officer
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Re: Best engine for boat?

I am not a mechanic. I do belong to a spearfishing forum here in Florida. Our boats go 40 to 100 miles offshore 12 months a year. Some guys run two three days a week. IN salt water pushing big boats with a full crew and 4-5 tanks each weighing at least 50 pounds each with full fuel tanks and ice. Hard conditions. I pulled some entries you can look at. Similar to what you want to do. For a 2 stroke they are very well liked. As far as 4 strokes the choice is Suzuki's.

http://www.spearfishingplanet.com/f28/blown-etec-powerhead-3134/index2.html
 
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