How big of a motor can I put on my '93 Nitro 17' boat?

Possibly looking at changing the motor on my boat to one thats ready to go. Don't care much to mess with the one I have. Cn someone please tell me how big I can go? Has a 90 Force on it now. Can I go to a 115 or so? Thanks, Sean

Re: How big of a motor can I put on my '93 Nitro 17' boat?

What is the boat rated for? The max hp will be on the ID tag. Remember, if your boat is rated for a 90hp max doesn't mean you can nudge it up 25 or so hp. Think about extra weight on the transom, an overrated motor could increase the chances of swamping your boat upon deceleration or just taking on a big ol wave from those annoying wake board boats. Let us know

Re: How big of a motor can I put on my '93 Nitro 17' boat?

Not sure how big it is rated for. The id tag is under the motor controls and haven't removed them yet. Have seen several Rick Clunn 17' boats with the 115 motors. I guess what I was wondering is the approximate weight difference between a 90hp and a 115hp? Thanks, Sean

Re: How big of a motor can I put on my '93 Nitro 17' boat?



This 14 footer has 125! Yeah, yeah, I know: The engine says 85 but then again, so does the capacity plate. The two Glastrons are each 15 feet long and are both rated for 90. The question is not how big can you put on, but how big do you want to put on. LOL

The largest Force you can get is 150.

Being a Nitro Bass Boat and 17 feet long, I would bet it is rated for more than 90, but you never know. The weight difference is only about 25 pounds on the pre-1994 Force engines and perhaps just a bit more with the Mercury version post 1994.

Re: How big of a motor can I put on my '93 Nitro 17' boat?

I found this website has a calculator about boat weight, speed, horsepower calculator. Check it out
http://www.go-fast.com/boat_speed_predictions.htm

Re: How big of a motor can I put on my '93 Nitro 17' boat?

tater76 said:

What is the boat rated for? The max hp will be on the ID tag. Remember, if your boat is rated for a 90hp max doesn't mean you can nudge it up 25 or so hp. Think about extra weight on the transom, an overrated motor could increase the chances of swamping your boat upon deceleration or just taking on a big ol wave from those annoying wake board boats. Let us know

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So.. with that said, would it be ok to hang a 90 4 stroke on there? SUBSTANTIALLY heavier than the 90 force, and heavier than a 115 2 stroke... Yet lots of people seem find with putting 4 strokes on boats that existed before there was even a mass produced 4 stroke outboard of that size.

Yes, i know there are POSSIBLE legal ramifications of overpowering, but I have yet to see an example of it. Also haven't seen a single case of insurance issues, even though I worked in insurance for quite a few years.

Think of it this way... People put in larger engines in vehicles, or use tuners to increase power on turbo vehicles. Sometimes substantially, 2x power increase isn't uncommon. You don't hear much about that...

Re: How big of a motor can I put on my '93 Nitro 17' boat?

When I lived in CT, over the course of 3 summers, we were boarded several times just doing spot checks for safety equipment. Twice, I was asked to raise the hatch so USCG could inspect the motor size. Not sure what they would have done if it was different, but just saying I have been checked.

I'd stick with the capacity plate. I won't get into the weight debate, as I have no first hand knowledge of the differences between an older 2 stroke and newer 4 stroke as far as weight is concerned.

Re: How big of a motor can I put on my '93 Nitro 17' boat?

DuckHunterJon said:

Twice, I was asked to raise the hatch so USCG could inspect the motor size.

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You sure they weren't just checking for non-marine parts on the engine (air filter, alternator, etc. that could cause an explosion if exposed to gasoline vapors)? I/O's don't typically have a max HP rating.

As far as the original post, I'd be willing to bet that a 115 is well within the capacity plate rating for a 17 ft. Nitro. I've got a 14-1/2 ft. fish-n-ski which is rated for 90, and I'm sure a Nitro is wider than mine in addition to the extra length, so it's rating is going to be a good bit more than 90 HP.

Re: How big of a motor can I put on my '93 Nitro 17' boat?

My neighbor has a 93 Nitro 17' Came stock with a 115. Biggest engine listed as a factory option was a 135. It will chine walk with the 115.He added a deck extention to fill in and square off the deck area. No more chine walk but will still hit 50mph

Re: How big of a motor can I put on my '93 Nitro 17' boat?

I have actually done something similar so I'll share my results.

I put a 1985 120hp johnson on my skeeter sd80 bass boat. The boat is 15.5' long. Max HP on the tag is 80, I think. The biggest different for me was going from a little 50hp yamaha that weighted about 200lbs to the v4 that weighs a little over 300lbs.

Coming off the throttle too fast can splash water over the back but hardly any actually makes it into the rear storage compartments, it just runs back off. With that being said, it sits no lower in the back than all the bass boats you see with the big engines on them. No water comes in unless I'm rocking in large swells in the middle of a lake or something. The other thing it does is porpoises pretty bad at slower speeds, even if I'm trimmed down. When I running faster than 35 or so it's smooth and the engine barely works. I think the biggest concern would be the added weight to your transom. Be sure it's not rotten. Oh, I have pretty bad torque steer too.

My boat handles great at WOT with no chine walking at all. Oddly enough, it handles better than my uncle's 21ft triton with a 225hp, at the same speeds. With my old paddle wheel ray marine fish finder, the boat used to top out at 38mph with the 50hp yammie, now it will do 68mph with the 120. I had it going faster once but the wheel came out of the water so I shut it down. I haven't verified with GPS yet but I have an app on my phone to do that now. I'm usually fishing out of my other boat now days.

Is the force 90 a v4? It sounds like what you're wanting to do won't change your weight nearly as much (if you keep to 2 stroke) so I'd change it if it were me.

Re: How big of a motor can I put on my '93 Nitro 17' boat?

How big ya got? If'n the new/more powerful motor isn't grossly heavier than what the boat was origionally rated for, go for it!

Remember it's not necessary to use all that power at once. But sometimes it's nice to have a few extra horses on hand ...?

Re: How big of a motor can I put on my '93 Nitro 17' boat?

DuckHunterJon said:

Twice, I was asked to raise the hatch so USCG could inspect the motor size.

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They were looking for a USCG-approved flame arrestor, not motor size.

Re: How big of a motor can I put on my '93 Nitro 17' boat?

I'm thinking I want to go 115-120hp but need to locate a motor to do it. Want to use the boat for tubing and other family fun as well. My boat already takes on some water if you let off the throttle rapidly. I know a 90 force can pull a tube easily. One question I have about redoing the motor I have is what needs to be spent or bought to finish the job after the rebuild kit is bought. I can get a complete kit for around $750. I already know it would have to be bored out (no idea what that costs either) so not sure how much I would have in the project when done if I go that route either. I'm just thinking if I buy another motor then I can be on the water tomorrow. However, I wouldn't mind keeping the motor I have as I have a title for it and it really is a super clean engine and sure it will be easy to redo. Any thoughts?....

93nitro said:

Possibly looking at changing the motor on my boat to one thats ready to go. Don't care much to mess with the one I have. Cn someone please tell me how big I can go? Has a 90 Force on it now. Can I go to a 115 or so? Thanks, Sean

Click to expand...

I am running a Yamaha 115 on mine