90 or 70 hp 4 stroke motor for 170cc

[russkatjak]

I want to upgrade my 170 cc from a 60 to a 70 or 90 hp 4 stroke. I like to fish but also take my friends out tubing or skiing. My 60 seems inadequate, any thoughts?

[rkola]

I have a 170 DC with a 70HP Yamaha 4S. It's got plenty of power to tow a skier, and will do around 35MPH with 2 people on board. I believe it is the maximum HP for which the 170 is rated.

Ron

[cj413]

I have a 70 hp two stroke on the back of my '06 170. I was told by the dealer that although the 4 stroke is quieter and more fuel efficient it is also a bit larger and heavier than a 2 stroke motor. What you gain in power you lose in weight. You can get a 75 hp 4 stroke but that is the maximum hp for the boat. My 70 2 stroke has more than enough power and i am very pleased with its performance.
CJ

[Triumphant]

I have a 75HP Yamaha 4stroke on my 170cc and it has more than enough power. It's weight however is a small issue. When I'm alone in the boat and can't get weight of another person up front, the boat rides bow high at slow speed. I've ordered a stabilizer plate (recommended on this site) from Bob's Machine Shop. Supposed to take care of slow speed planing. I'll post how well it works after installation. Just my two cents.

[elroy]

I have a 2006 75hp 2 stroke etech which is tons of power and light. max hp on a 2006 is 75 hp. With just me I have hit a top speed of 43.1 mph on gps. with 2 people it"s 36-37 mph

[foxbo]

Correct me if I'm wrong but I was told 75 horse was the max for a 170. I wanted to put a 90 2 stroke on mine but was told it would invalidate the warranty. Plate near engine says 288 max weight, and the owners manual says 75 horse max. With that said what i don't understand is the 04 90 horse was well under the max weight plate. Also I understand prior to 04 you could get a 90 on a new 170.

[elroy]

I think you mean 388 max lbs

[foxbo]

Yeah, thanks for corredting me, been up alnight working.

[Triumphant]

My plate says 388lbs max which I am close to with my 75 4stroke Yamaha. I remember though (whether I read it or was told it) the only difference between a 75hp and a 90hp was a computer chip. Maybe I'm wrong, but if the weight of the engine is still the same, would it void the warranty if you switched chips? In my opinion, and it's only an opinion, the 75 is plenty for the 170. Enough to pull a skiier and and I can slow it down to 2.2 mph by the gps to troll for salmon. Plus it takes barely any gas, I can barely hear it running, and I don't have to smell it if the wind is hitting me in the face.

[foxbo]

Check your owners manual, mine says 75 horse max. That is what baffles me, the 90 Yamaha I looked at was well under the transom plate weight. Doesn't matter as it will invalidate the warranty and I'm not going to do that. As long as my 60 is good on gas and sips oil, I'll stay happy.

Just remembered I was told Triumph changed the max rating becuse of the 4 stroke weight. Go to Yamaha's website and check the weight on the 04 90 horse, well under the max.