Thinking about 140 Looper on my 175

[CLM65]

The boat is in my sig. A 95 175 osprey

Sorry, I missed that.  Not really an old boat, so probably not weighed down with soggy foam.

[BMAC1988]

Yea I don't think I have too much soggy foam. When comparing to my boat with the 170 models mentioned remember that the 170s are a good 700lbs light than my 175, not to mention the added motor weight of my 88 over a 70, added weight of a T-top, dual batteries, fuel cap, etc. I figure I'm floating around 3300lbs-3500lbs after people and what not like I mentioned earlier.

[BMAC1988]

Took the boat over to our shop yesterday to do some work on it. Pulled the plugs out to replace them with new ones and to run a compression check. No surprise, our compression tester is missing 

I examined the plugs and they were plenty wet and just as I suspected were in need of replacing. I went to advance and got some new plugs, tried to get champion plugs but they didn't have any for I got the crossed over NGK plugs and gapped them to .030". I did check timing and while idling it was steady on about 7° and I while driving up to about 2000 advanced to about 12° or so. I do think its time to replace the coils as one of them has chunks out of epoxy not to mention I can't remember that they've ever been changed.

[JimInPB]

If you want fuel economy, you really want to look at the modern 4-strokes.  All day fishing in a 22' with a 200hp Yammy, doing a lot of running & gunning 20+ miles off shore, only burned about 20 gallons.

140 sounds like a lot of horses for a 17.  What is the max HP listed on your coast guard plate?  Liability goes off the charts as soon as the HP goes above the number listed on the plate.  My insurance company will not cover a boat with HP that is over the number on the plate.

I've driven mid 1980's 17s with 60, 70, 90 & 115 hp.  60 was only good for 2 average adults & basic gear in modest conditions.  70 was slightly better.  90 was a good match unless you loaded the boat like a total pig.  115 was 1 notch below scary. 

If you need to load the boat with so much stuff that a 115 will not do the job to your liking, then you might wish to consider a larger hull as well as a larger motor.

[BMAC1988]

im seriously thinking about a Suzuki df140 4stroke motor now, and maybe a smaller HP version if one becomes available. from my research these motors are very light, fuel efficient, and are very dependable. 

[fitz73222]

im seriously thinking about a Suzuki df140 4stroke motor now, and maybe a smaller HP version if one becomes available. from my research these motors are very light, fuel efficient, and are very dependable.

Very light is a relative term, 396# on a 175 AS is crazy heavy. The boat will not perform anywhere near the engines capabilities. The max hull speed is probably really in the mid 40's so anything else over that is just going to turn into squirrelly performance. You're going to wind up running it at the same cruise speed as with a 90 hp anyway, probably in the low 30's in a mild chop. Of course your scuppers will be well underwater and you get to deal with that mess. Also say by by to insurance on it. So if your intent was to get endorsements for this upgrade, mine would be to save your money!

[RickK]

My vote too - ^^^  Save the coin for some bling on the boat

[BMAC1988]

as I mentioned im not concerned with top speed nearly as much as I am about fuel efficiency and time-to-plane, and obviously the cost of the swap. compared to other 4-stroke motors the DF is very light and is actually only 6lbs heavier than a 115 ETEC (390lbs). im not deadset on a 140,but wouldnt be against it if one became available for cheap, 140 is my max that I would put on the boat. I wouldn't put anything smaller than a 115hp motor on this boat. according to the continuouswave calculator for hp and speed, the 140 would put me at 47mph and the 115 would be 42 which coincides with what others have reported with 115s. right now my cruise speed is 27-28mph getting around but never over 4mpg. my scuppers are not underwater right now long as i don't have dual coolers in the back and even with dual coolers the scuppers aren't under water until I get behind the leaning post. we went scalloping a few weekends ago and with my 185lbs butt standing in the back of the boat the scuppers were just barely in the water.  after I saw that I wasn't quite as concerned with the 90lbs of added weight back there for a newer motor.   

[wingtime]

I think a healthy 140 looper will push the 175 an easy 50 mph.  WAY too fast for that hull if you ask me.  in any kind of a chop 30mph is more than fast enough. Any faster would beat you to death.

[Jmac]

I have a '72 17'AS with an 03 90hp Suzuki 4 stroke on her. I couldn't imagine anything bigger pushing her along. With 2 guys in flat water we ran about 44 mph this past weekend. The foam in the hull is definitely wet as well ... ( the winter project..)

[BMAC1988]

I just ran some numbers based on my own performance data and the fuel consumption data ive found online. assuming a 140 Suzuki would be pushing my boat the same 30mph at 4k rpm as my 88 rude (which id think it would actually be pushing it faster given itd be swinging a bigger/more-pitch prop) id be getting 7.5mpg, that's DOUBLE the mileage im getting now. I also looked at the fuel consumption of the same motor but a 115 version and it actually burns more fuel and drops that number to 6.8. at WOT assuming itd push my boat 47mph id still be getting just over 4mpg which is better than im getting now at optimum cruise.

the 90/115/140 all weigh the same and is going to be about 100lbs more than my rude. ive also read something about the the 140 having an offset powerhead which shifts more of the engine weight forward to ease stress on the transom, which would also help slightly in how far down in the water it sits.

I really wish I knew somebody with one of these that I could try out. curiosity is killing me. as is the appeal of 7+mpg