Posted by Supersport305 on 10/09/17 - 5:05 PM
#1
Hi all,
The current 2005 Mercury 40-hp 2-stroke on my 13 started running rough (louder, knocking) during a recent trip, causing me to pull it out of the water until I could figure what was wrong. After going through everything I had considered (cleaned carbs, tested spark, compression (120, 120, 120), I got a hint that it may be the stator, and rather than to deal with pulling the fly-wheel, I took it in to a local shop. Note, the engine has no noticeable performance loss, and no trouble starting on the first try every time.
One week later, the shop had pulled the lower-unit, and found the splines on the driveshaft to be twisted.
Running without the lower-unit, the engine was still making a knocking/pinging noise, which prompted them to take a look at the power-head. They tested the compression and got 90-120-120. Sticking a scope into the top cylinder, the piston is pitted & the cylinder is heavily scored. The other two cylinders look perfect.
The shop thinks the damage is likely from picking up a submerged rope at high rpms. The noise started while running the ICW.
Insurance has mentioned they will likely total the engine.
I've just noticed that Mercury 2-strokes are no longer available, and a 40 hp 2-stroke weighs ~ >60 lbs than the current 2-stroke I have on back.
I've seen a lot of talk about that much weight being an issue, even the current 2-stroke being too much weight. It is heavier in the back than I would like already, but I could also move around the fuel tank & batteries to compensate, as well as add some other sort of ballast if needed.
A 30 hp 4-stroke Mercury still weighs more than the current setup. As is, the boat will currently do 30 mph with two people @ WOT, and I would like to keep the speed it has now.
I believe I could also replace the powerhead of the current outboard, but worry about reliabilty (maybe I shouldn't), and hate to pass the opportunity to put a new engine under warranty on the boat.
I also see that the new Yamaha 40's are lighter, although still heavier than the current outboard.
Asking for input!
Thanks!
Edited by Joe Kriz on 10/09/17 - 5:17 PM
Posted by max366 on 10/12/17 - 6:19 AM
#5
Take a look at the Suzuki 30HP 4 stroke motor. Light (I think its' 153 lbs by memory) and strong with some nice features. You can buy the motor from places like Porta Bote and it comes with prop, control box, fuel tank, etc. Everything needed but control cables. Also includes a 6 yr warranty. It may not run as quickly as your 40hp motor but my 2002 13ft Sport runs about 28 mph and the hull has a vee bottom, so your boat should run faster then a 2002 hull. I love mine- it's quiet, starts instantly, is great on fuel and no smoke.
Posted by Supersport305 on 10/13/17 - 9:22 AM
#6
Thanks Max, I'll check it out!
I've recently noticed that Mercury makes 2 different 40 hp 4-strokes.
The one I was referring to was the command-thrust option, weighing 266 lbs. Apparently the other model without "command-thrust" comes in at only 216 lbs, ~ 12 lbs heavier than my current outboard. I'm thinking I'll likely just go with this option to maintain the same power, and just compensate by moving the fuel tank forward or mounting a heavy cooler up on the bow.