Horsepower range for AS170

[KelpKritter]

Unfortunately a major mechanical issue took place this weekend with my 90 HP Mercury.  After speaking with my mechanic it is his opinion that I look to replace the engine rather than making the fix.  I have looked through all of my original spec sheets and manuals for my 1978 Aquasport 170 but cannot find the listed horsepower range for that boat.  

Performance wise I was very pleased with the 90 HP and would like to replace it with the same size engine but need to keep my options open.  How low can I go in horsepower and still expect good performance on this hull?

Thanks for your insight.

Dave

[saltfly]

You can go as low as 70. with the newer motors a 70 would puch your boat almost as fast as your older one maybe ever faster. But I like a 90 on that boat. I think the power is great for that boat. power to weight ratio is just about right. At least I feel that way.

[KelpKritter]

Maybe I was not as clear as I thought with my previous post. I currently have a 1989 90hp Mercury outboard mounted on a 1978 AS170.  I very likely will be buying a new motor for the boat and am looking to find out what the recommended horsepower rating is for that hull. I am willing to go to a lower horsepower rating if I do not lose significant performance.  Just trying to figure what my motor options are when searching for a replacement motor.

Thanks again,

Dave

[saltfly]

Sorry I posted that last reply to the wrong thread. Sooooo I change it to reply to you post.

[KelpKritter]

Thanks for the input.

Dave

[akbridge]

I think those older AS were rated for 90Hp.  I would stay with that.  More power generally gets you very little speed.  I think Rickk runs a 115 and tops out at 42.  I have a 90 and have seen 40 but generally ran at 39.  Save a few dollars and pounds and keep the 90.

[KelpKritter]

The older 90hp pushed her along at 36 mph at top end.  More than enough speed for the area I fish on the west coast.  Right now looking at weight of newer motors, both two and four strokes, in relationship to the older Mercury on the boat now in order to see where I might go with the new purchase if it comes to that.

Dave

[RickK]

I think those older AS were rated for 90Hp.  I would stay with that.  More power generally gets you very little speed.  I think Rickk runs a 115 and tops out at 42.  I have a 90 and have seen 40 but generally ran at 39.  Save a few dollars and pounds and keep the 90.

Nope - saw 40 only.

[fitz73222]

Hey KelpKritter,

Now you get to deal with the battle of the bulge. Your 90 Merc was around 305#. The DFI and fourstroke engines are going to be 50-100# heavier in the same horsepower class, so be prepared for that and also if the boat self bailed before it may no longer with the weight gain. There will be a lot of people who will jump on this with their favorite brand so get ready for that noise.

[KelpKritter]

Thanks for the update on the weight of that engine, never could find any info on the actual weight of that thing.  With the current Mercury it is no longer self bailing so that is not an issue as I have a pump that sends water on the deck overboard.

I have heard good things from a couple of guys in my fishing club about the Suzuki four strokes and they are the lightest on the market at 340 and change.  Any thoughts from this crowd?

Not looking forward to re-powering and it might take some time but it looks to be the best solution at this point.

Dave

[gran398]

Take a  good look at a quality 90 hp two stroke 3 cylinder Yamaha or Tohatsu. Basically, a bored-out version of the old Johnnie 70 hp 3 cyl. looper.

Quick hole shot..excellent thru the mid-range...and great top-end. And decent to good fuel economy with the correct stainless prop.

2K or less should buy a honey-pie.

[GoneFission]

I would give a serious look at the Mercury Optimax 90/115/125.  These are 3 cylinder, direct-injected engines that weigh in at 375 lbs (all HP are the same weight).  The difference in HP is tied to engine programming, so the 90 has similar grunt to the 115 and 125, but gives up some power in mid and upper range.  All are 1.5 liter engines and run around 5500 rpm.    

If I was repowering my CCP right now, I would consider a pair of the 115 Optimax's - interesting thing is - two 115 Optimax engines cost less than a single 225 Optimax costs - don't quite figure that one out...  

[MarshMarlowe196]

As far as Suzuki's go, my personal experience and what I've heard has been all good things.  

Heard good things about Opti's too, but they seem to be a little overweight for a 2 stroke and the air compressors have a history of premature failure.

I would go with Gran's suggestion- if you can find a used 3 cylinder yamaha in good shape with low hours (since they don't make them anymore), that's a great, simple, lightweight engine that get's decent gas mileage and will last you a very long time.  Had one on a 1720 Key West with a 19 gallon tank that I never burned through - was a great setup.

[bandaidmd]

when i repowered from a 90hp v4 johns ( supposed to be 300 lb) last summer i ended up going with a 90 etec , if memory serves it was next to the lighest avail @340?. I bought a leftover at a local dealer but bass pro had mercs at a good price.