Posts: 3469
Location: Elk River, Minnesota | Nomad,
I think your consideration with the weight is a good consideration to have. I am assuming your boat is a 1990 as well or is it much newer than that?
If my assumption is correct in that it is a 1990 model, the boat may not be able to handle the extra weight...not because of the power or too much weight on the transom...those are built to take on much more than what we put on there...but for level floatation. If memory serves me correctly, the USCG clears the HP and weight capacities of the rig so that it sits with level floatation in the water... along with safety on HP. So...going to a 90hp as you are thinking may not be the best situation as your boat would most likely "squat" significantly in the water. This becomes a bigger issue if you are in following seas....easier to swamp the boat, and that is a huge safety concern. Your old motor weighs just a touch more than the 70 yamaha so weight wise, that is a wash essentially...
The 4 stroke 70 yamaha as compared to your 1990 mercury will be rated in the same manner (70hp and 75hp at the prop) as I believe that particular rating started in the mid-late 80's. So...that is the closest you will get for comparison. The 70 will be slower out of the hole, will run very smooth and will definitely troll down better than your old 75, and you won't gum up spark plugs as no oil mixture is being used. The boat will sit a level because you are going down in weight, but it will if you went with a 90.
As for the Etec, the original designs, up and through around 2007 or so did have problems as it was essentially a redesign of the FICHT ram injection system. It has been a good 10 years since those issues were happening, and the bugs have been worked out. The efficiency of the etec motor will be just as good, if not better than some of the 4 strokes out there, and they troll down very very well... Absolutely a minimum of any sort of smoke...you won't be filled with smoke in your eyes and nose if you are backtrolling. At idle, it'll be maybe a touch louder than a 4 stroke in the same HP, but where you will find the main difference is in your low end power. With my etec, I can have a nice conversation with anyone in the boat without having to speak louder than my normal voice. It's that quiet.... The warranty you get with the etec is outstanding, the maintenance and winter storage of the engine is about a 3 minute process (all done electronically), and...you get the quicker response of a 2 stroke. Size wise, it will look good on your rig and not seem like a monstrosity back there which is what some 4 strokes look like on the back of some boats. The etec 75 or 90 are built on the same powerhead, so the 75 is a detuned engine, while the 90 is a full capacity engine (so to speak) so they can sell at different price points. They both weight in a 320 pounds so you are not increasing by a huge amount (55 pounds), which is really minimal as well. That is roughly the weight of a deep cycle battery. The beauty of going etec, is you can max out if you want, and you will get a rig that really will perform well for heavier weights in the boat (friends and their gear). Even if you go with the etec 75, you will get much better results overall.
2 stroke by design will have a much stronger power curve in the lower rpm range, and is great when you need to get up on plane quickly for whatever reason you might have.
I feel you have your mind made up with the yamaha, but if you do decide to take a closer look at etec, I think you might find it is a great design, and if you get more responses about etecs (and you are open to that option), you might be really happy going in that direction.
No matter what you choose, you will have a good motor...both are solid!!
Steve
Steve
Edited by VMS 2/7/2019 11:58 AM
|
